| 1 | Biol. Psychiatry 2006 Jul 60: 123-31 |
|---|---|
| PMID | 16843095 |
| Title | The genetics and biology of DISC1--an emerging role in psychosis and cognition. |
| Abstract | In the developing field of biological psychiatry, DISC1 stands out by virtue of there being credible evidence, both genetic and biological, for a role in determining susceptibility to schizophrenia and related disorders. We highlight the methodologic paradigm that led to identification of DISC1 and review the supporting genetic and biological evidence. The original finding of DISC1 as a gene disrupted by a balanced translocation on chromosome 1q42 that segregates with schizophrenia, bipolar disorder, and recurrent major depression has sparked a number of confirmatory linkage and association studies. These indicate that DISC1 is a generalizable genetic risk factor for psychiatric illness that also influences cognition in healthy subjects. DISC1 has also been shown to interact with a number of proteins with neurobiological pedigrees, including NDEL1 (NUDEL), a key regulator of neuronal migration with endo-oligopeptidase activity, and PDE4B, a phosphodiesterase that is critical for cyclic adenosine monophosphate signaling and that is directly linked to learning, memory, and mood. Both are potential "drug" targets. DISC1 has thus emerged as a key molecular player in the etiology of major mental illness and in normal brain processes. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 2 | Hum. Mol. Genet. 2006 Nov 15: 3313-23 |
| PMID | 17035248 |
| Title | DISC1-NDEL1/NUDEL protein interaction, an essential component for neurite outgrowth, is modulated by genetic variations of DISC1. |
| Abstract | Disrupted-In-schizophrenia-1 (DISC1) is a unique susceptibility gene for major mental conditions, because of the segregation of its genetic variant with hereditary psychosis in a Scottish pedigree. Genetic association studies reproducibly suggest involvement of DISC1 in both schizophrenia and bipolar disorder in several ethnic groups. The DISC1 protein is multifunctional, and a pool of DISC1 in the dynein motor complex is required for neurite outgrowth in PC12 cells as well as proper neuronal migration and dendritic arborization in the developing cerebral cortex in vivo. Here, we show that a specific interaction between DISC1 and nuclear distribution element-like (NDEL1/NUDEL) is required for neurite outgrowth in differentiating PC12 cells. Among several components of the dynein motor complex, DISC1 and NDEL1 are selectively upregulated during neurite outgrowth upon differentiation in PC12 cells. The NDEL1 binding site of DISC1 was narrowed down to a small portion of exon 13, corresponding to amino acids 802-835 of DISC1. We demonstrate that genetic variants of DISC1, proximal to the NDEL1 binding site, affect the interaction between DISC1 and NDEL1. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 3 | Biochem. Soc. Trans. 2007 Nov 35: 1283-6 |
| PMID | 17956330 |
| Title | Dissecting DISC1 function through protein-protein interactions. |
| Abstract | Disrupted in schizophrenia 1 (DISC1) is emerging in the eyes of many as the most promising candidate of all the schizophrenia risk genes. This viewpoint is derived from the combination of genetic, clinical, imaging and rapidly advancing cell biology data around this gene. All of these areas have been reviewed extensively recently and this review will point you towards some of these excellent papers. My own personal view of the potential importance of DISC1 was echoed in a recent review which suggested that DISC1 may be a 'Rosetta Stone' for schizophrenia research [Ross, Margolis, Reading, Pletnikov and Coyle (2006) Neuron 52, 139-153]. Our own efforts to try to understand the function of DISC1 were through identification of its protein-binding partners. Through an extensive Y2H (yeast two-hybrid) and bioinformatics effort we generated the 'DISC1-Interactome', a comprehensive network of protein-protein interactions around DISC1. In two excellent industry-academia collaborations we focused on two main interacting partners: NDEL1 (nudE nuclear distribution gene E homologue-like 1), an enigmatic protein which may have diverse functions as both a cysteine protease and a key centrosomal structural protein; and PDE4B, a cAMP-specific phosphodiesterase. I will review the work around these two protein complexes in detail. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 4 | Curr. Opin. Neurobiol. 2007 Feb 17: 95-102 |
| PMID | 17258902 |
| Title | Role of DISC1 in neural development and schizophrenia. |
| Abstract | How can we hope to explain mechanistically the schizophrenic phenotype? Perhaps through the reductionist approach of genetics, which is beginning to yield biological clues. Growing evidence supports the view that the well-established genetic risk factor DISC1 plays an important role in schizophrenia biology by interacting with FEZ1 and NDEL1 during neurodevelopment and with the phosphodiesterase PDE4B in neuronal cell signalling. Thus, DISC1 and its pathways support the neurodevelopmental hypothesis of schizophrenia and provide a mechanistic explanation for the characteristic cognitive deficits. Genetic variants of DISC1 also predispose to related affective (mood) disorders. As a consequence, we can speculate on the mechanisms of DISC1 action and possible routes to treatment for these common, debilitating brain disorders. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 5 | Curr. Opin. Neurobiol. 2007 Feb 17: 95-102 |
| PMID | 17258902 |
| Title | Role of DISC1 in neural development and schizophrenia. |
| Abstract | How can we hope to explain mechanistically the schizophrenic phenotype? Perhaps through the reductionist approach of genetics, which is beginning to yield biological clues. Growing evidence supports the view that the well-established genetic risk factor DISC1 plays an important role in schizophrenia biology by interacting with FEZ1 and NDEL1 during neurodevelopment and with the phosphodiesterase PDE4B in neuronal cell signalling. Thus, DISC1 and its pathways support the neurodevelopmental hypothesis of schizophrenia and provide a mechanistic explanation for the characteristic cognitive deficits. Genetic variants of DISC1 also predispose to related affective (mood) disorders. As a consequence, we can speculate on the mechanisms of DISC1 action and possible routes to treatment for these common, debilitating brain disorders. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 6 | Cell 2007 Sep 130: 1146-58 |
| PMID | 17825401 |
| Title | Disrupted-In-Schizophrenia 1 regulates integration of newly generated neurons in the adult brain. |
| Abstract | Adult neurogenesis occurs throughout life in discrete regions of the adult mammalian brain. Little is known about the mechanism governing the sequential developmental process that leads to integration of new neurons from adult neural stem cells into the existing circuitry. Here, we investigated roles of Disrupted-In-schizophrenia 1 (DISC1), a schizophrenia susceptibility gene, in adult hippocampal neurogenesis. Unexpectedly, downregulation of DISC1 leads to accelerated neuronal integration, resulting in aberrant morphological development and mispositioning of new dentate granule cells in a cell-autonomous fashion. Functionally, newborn neurons with DISC1 knockdown exhibit enhanced excitability and accelerated dendritic development and synapse formation. Furthermore, DISC1 cooperates with its binding partner NDEL1 in regulating adult neurogenesis. Taken together, our study identifies DISC1 as a key regulator that orchestrates the tempo of functional neuronal integration in the adult brain and demonstrates essential roles of a susceptibility gene for major mental illness in neuronal development, including adult neurogenesis. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 7 | Gene Expr. Patterns 2007 Jun 7: 672-9 |
| PMID | 17482883 |
| Title | Expression profiles of ndel1a and ndel1b, two orthologs of the NudE-Like gene, in the zebrafish. |
| Abstract | NudE-Like (NDEL1/NUDEL), through its interaction with LIS1 and DISC1, has been implicated in the etiology of neurological disorders such as lissencephaly and schizophrenia, respectively. Subsequently, a large portion of the research done on the function of NDEL1 has been specifically targeted to its role in brain development while ignoring its function in other developing and adult tissues. To begin a more global exploration of NDEL1's function, this study characterizes the developmental expression pattern of the NDEL1 orthologs in the zebrafish embryo. Our bioinformatic analyses identified two NDEL1 orthologs in the zebrafish, NDEL1a and NDEL1b. NDEL1a is expressed predominantly in the anterior central nervous system (CNS), trigeminal ganglia, and eyes while NDEL1b is expressed in the developing somites and, later, in the CNS. In addition to the spatial differences in their expression patterns, these genes are also individually regulated in their temporal expression. Both are expressed maternally but at later time-points there are subtle differences. NDEL1a expression is lost between 6 and 12 hpf but then increases to a higher, near steady state, level from 72 to 120 hpf. NDEL1b expression decreases from 3 to 36 hpf and subsequently increases from 36 to 120 hpf. The non-overlapping expression patterns of these two orthologs may indicate that they have split the functional role of the one NDEL1 gene present in mammalian species. The temporal and spatial regulation of these two orthologs will aid in the characterization of the multiple functions of this gene in both the developing and mature organism. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 8 | Mol. Psychiatry 2008 Dec 13: 1138-48, 1069 |
| PMID | 18762802 |
| Title | Nuclear DISC1 regulates CRE-mediated gene transcription and sleep homeostasis in the fruit fly. |
| Abstract | Disrupted-in-schizophrenia-1 (DISC1) is one of major susceptibility factors for a wide range of mental illnesses, including schizophrenia, bipolar disorder, major depression and autism spectrum conditions. DISC1 is located in several subcellular domains, such as the centrosome and the nucleus, and interacts with various proteins, including NudE-like (NUDEL/NDEL1) and activating transcription factor 4 (ATF4)/CREB2. Nevertheless, a role for DISC1 in vivo remains to be elucidated. Therefore, we have generated a Drosophila model for examining normal functions of DISC1 in living organisms. DISC1 transgenic flies with preferential accumulation of exogenous human DISC1 in the nucleus display disturbance in sleep homeostasis, which has been reportedly associated with CREB signaling/CRE-mediated gene transcription. Thus, in mammalian cells, we characterized nuclear DISC1, and identified a subset of nuclear DISC1 that colocalizes with the promyelocytic leukemia (PML) bodies, a nuclear compartment for gene transcription. Furthermore, we identified three functional cis-elements that regulate the nuclear localization of DISC1. We also report that DISC1 interacts with ATF4/CREB2 and a corepressor N-CoR, modulating CRE-mediated gene transcription. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 9 | Biochem. Biophys. Res. Commun. 2008 Dec 377: 1091-6 |
| PMID | 18983980 |
| Title | DISC1, PDE4B, and NDE1 at the centrosome and synapse. |
| Abstract | Disrupted-In-schizophrenia 1 (DISC1) is a risk factor for schizophrenia and other major mental illnesses. Its protein binding partners include the Nuclear Distribution Factor E Homologs (NDE1 and NDEL1), LIS1, and phosphodiesterases 4B and 4D (PDE4B and PDE4D). We demonstrate that NDE1, NDEL1 and LIS1, together with their binding partner dynein, associate with DISC1, PDE4B and PDE4D within the cell, and provide evidence that this complex is present at the centrosome. LIS1 and NDEL1 have been previously suggested to be synaptic, and we now demonstrate localisation of DISC1, NDE1, and PDE4B at synapses in cultured neurons. NDE1 is phosphorylated by cAMP-dependant Protein Kinase A (PKA), whose activity is, in turn, regulated by the cAMP hydrolysis activity of phosphodiesterases, including PDE4. We propose that DISC1 acts as an assembly scaffold for all of these proteins and that the NDE1/NDEL1/LIS1/dynein complex is modulated by cAMP levels via PKA and PDE4. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 10 | Novartis Found. Symp. 2008 -1 289: 208-16; discussion 216-21, 238-40 |
| PMID | 18497105 |
| Title | What can we learn from the disrupted in schizophrenia 1 interactome: lessons for target identification and disease biology? |
| Abstract | Emerging genetic and biological data strongly supports Disrupted in schizophrenia 1 (DISC1) as a schizophrenia risk gene of great significance for not only understanding the underlying causes of schizophrenia and related disorders but potentially to open up new avenues of treatment. DISC1 appeared to be a very enigmatic protein upon the initial disclosure of its protein sequence. Though it contained some well-characterized protein domains, they did not reveal anything about possible function. Recently, the identification of its binding partners has revealed an incredible diversity of potential cellular and physiological functions. In an attempt to capture this information we set out to generate a comprehensive network of protein-protein interactions (PPIs) around DISC1. This was achieved by utilizing iterative yeast-two hybrid screens, combined with detailed pathway and functional analysis. This so-called 'DISC1 interactome' contains many novel PPIs and has provided a molecular framework to explore the function of DISC1. Interrogation of the interactome has shown DISC1 to have a PPI profile consistent with that of an essential synaptic protein, which fits well with the underlying molecular pathology observed at the synaptic level and the cognitive deficits seen behaviourally in schizophrenics. Furthermore, potential novel therapeutic targets have also emerged as we have characterized in detail the interactions with the phosphodiesterase PDE4B in collaboration with the Porteous and Houslay labs, and with NDEL1-EOPA with Hayashi and colleagues. Many components of the interactome are themselves now being shown to be schizophrenia risk genes, or to interact with other risk genes, emphasising the power of protein interaction studies for revealing the underlying biology of a disease. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 11 | Novartis Found. Symp. 2008 -1 289: 208-16; discussion 216-21, 238-40 |
| PMID | 18497105 |
| Title | What can we learn from the disrupted in schizophrenia 1 interactome: lessons for target identification and disease biology? |
| Abstract | Emerging genetic and biological data strongly supports Disrupted in schizophrenia 1 (DISC1) as a schizophrenia risk gene of great significance for not only understanding the underlying causes of schizophrenia and related disorders but potentially to open up new avenues of treatment. DISC1 appeared to be a very enigmatic protein upon the initial disclosure of its protein sequence. Though it contained some well-characterized protein domains, they did not reveal anything about possible function. Recently, the identification of its binding partners has revealed an incredible diversity of potential cellular and physiological functions. In an attempt to capture this information we set out to generate a comprehensive network of protein-protein interactions (PPIs) around DISC1. This was achieved by utilizing iterative yeast-two hybrid screens, combined with detailed pathway and functional analysis. This so-called 'DISC1 interactome' contains many novel PPIs and has provided a molecular framework to explore the function of DISC1. Interrogation of the interactome has shown DISC1 to have a PPI profile consistent with that of an essential synaptic protein, which fits well with the underlying molecular pathology observed at the synaptic level and the cognitive deficits seen behaviourally in schizophrenics. Furthermore, potential novel therapeutic targets have also emerged as we have characterized in detail the interactions with the phosphodiesterase PDE4B in collaboration with the Porteous and Houslay labs, and with NDEL1-EOPA with Hayashi and colleagues. Many components of the interactome are themselves now being shown to be schizophrenia risk genes, or to interact with other risk genes, emphasising the power of protein interaction studies for revealing the underlying biology of a disease. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 12 | Hum. Mol. Genet. 2008 Aug 17: 2462-73 |
| PMID | 18469341 |
| Title | Elucidating the relationship between DISC1, NDEL1 and NDE1 and the risk for schizophrenia: evidence of epistasis and competitive binding. |
| Abstract | DISC1 influences susceptibility to psychiatric disease and related phenotypes. Intact functions of DISC1 and its binding partners, NDEL1 and NDE1, are critical to neurodevelopmental processes aberrant in schizophrenia (SZ). Despite evidence of an NDEL1-DISC1 protein interaction, there have been no investigations of the NDEL1 gene or the relationship between NDEL1 and DISC1 in SZ. We genotyped six NDEL1 single-nucleotide polymorphisms (SNPs) in 275 Caucasian SZ patients and 200 controls and tested for association and interaction between the functional SNP Ser704Cys in DISC1 and NDEL1. We also evaluated the relationship between NDE1 and DISC1 genotype and SZ. Finally, in a series of in vitro assays, we determined the binding profiles of NDEL1 and NDE1, in relation to DISC1 Ser704Cys. We observed a single haplotype block within NDEL1; the majority of variation was captured by NDEL1 rs1391768. We observed a significant interaction between rs1391768 and DISC1 Ser704Cys, with the effect of NDEL1 on SZ evident only against the background of DISC1 Ser704 homozygosity. Secondary analyses revealed no direct relationship between NDE1 genotype and SZ; however, there was an opposite pattern of risk for NDE1 genotype when conditioned on DISC1 Ser704Cys, with NDE1 rs3784859 imparting a significant effect but only in the context of a Cys-carrying background. In addition, we report opposing binding patterns of NDEL1 and NDE1 to Ser704 versus Cys704, at the same DISC1 binding domain. These data suggest that NDEL1 significantly influences risk for SZ via an interaction with DISC1. We propose a model where NDEL1 and NDE1 compete for binding with DISC1. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 13 | J. Neurosci. 2008 Apr 28: 3839-45 |
| PMID | 18400883 |
| Title | Insolubility of disrupted-in-schizophrenia 1 disrupts oligomer-dependent interactions with nuclear distribution element 1 and is associated with sporadic mental disease. |
| Abstract | Disrupted-in-schizophrenia 1 (DISC1) and other genes have been identified recently as potential molecular players in chronic psychiatric diseases such as affective disorders and schizophrenia. A molecular mechanism of how these genes may be linked to the majority of sporadic cases of these diseases remains unclear. The chronic nature and irreversibility of clinical symptoms in a subgroup of these diseases prompted us to investigate whether proteins corresponding to candidate genes displayed subtle features of protein aggregation. Here, we show that in postmortem brain samples of a distinct group of patients with phenotypes of affective disorders or schizophrenia, but not healthy controls, significant fractions of DISC1 could be identified as cold Sarkosyl-insoluble protein aggregates. A loss-of-function phenotype could be demonstrated for insoluble DISC1 through abolished binding to a key DISC1 ligand, nuclear distribution element 1 (NDEL1): in human neuroblastoma cells, DISC1 formed expression-dependent, detergent-resistant aggregates that failed to interact with endogenous NDEL1. Recombinant (r) NDEL1 expressed in Escherichia coli selectively bound an octamer of an rDISC1 fragment but not dimers or high molecular weight multimers, suggesting an oligomerization optimum for molecular interactions of DISC1 with NDEL1. For DISC1-related sporadic psychiatric disease, we propose a mechanism whereby impaired cellular control over self-association of DISC1 leads to excessive multimerization and subsequent formation of detergent-resistant aggregates, culminating in loss of ligand binding, here exemplified by NDEL1. We conclude that the absence of oligomer-dependent ligand interactions of DISC1 can be associated with sporadic mental disease of mixed phenotypes. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 14 | Rev Neurosci 2009 -1 20: 321-30 |
| PMID | 20397618 |
| Title | DISCopathies: brain disorders related to DISC1 dysfunction. |
| Abstract | During the last decade, disrupted-in-schizophrenia 1 (DISC1) has emerged as a protein involved in the pathogenesis of chronic mental diseases such as schizophrenia, or recurrent affective disorders. Its multiple functions include regulating corticogenesis, synapse integrity and adult neurogenesis, indicating a key role in the hard-wiring and the maintenance of communicative abilities of the brain. From its cellular functions, the DISC1 protein is a 'molecular facilitator', which interacts with a quartenary complex including NDEL1, NDE1, LIS1, as well as the signaling molecules, GSK-3beta, PDE4B, and others. DISC1 oligomerizes, can form misassembled dysfunctional multimers as well as disease-associated insoluble protein complexes which qualify these diseases as protein conformational disorders. Disease categories ultimately serve the goal of defining pathophysiological conditions amenable to similar and efficient (pharmaco) therapies. Here, it is proposed to classify brain disorders related to dysfunctional DISC1 protein as one disease entity, that is, as DISCopathies. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 15 | Biol. Psychiatry 2009 Jun 65: 1055-62 |
| PMID | 19251251 |
| Title | Association between genes of Disrupted in schizophrenia 1 (DISC1) interactors and schizophrenia supports the role of the DISC1 pathway in the etiology of major mental illnesses. |
| Abstract | Disrupted in schizophrenia 1 (DISC1) is currently one of the most interesting candidate genes for major mental illness, having been demonstrated to associate with schizophrenia, bipolar disorder, major depression, autism, and Asperger's syndrome. We have previously reported a DISC1 haplotype, HEP3, and an NDE1 spanning tag haplotype to associate to schizophrenia in Finnish schizophrenia families. Because both DISC1 and NDE1 display association in our study sample, we hypothesized that other genes interacting with DISC1 might also have a role in the etiology of schizophrenia. We selected 11 additional genes encoding components of the "DISC1 pathway" and studied these in our study sample of 476 families including 1857 genotyped individuals. We performed single nucleotide polymorphism (SNP) and haplotype association analyses in two independent sets of families. For markers and haplotypes found to be consistently associated in both sets, the overall significance was tested with the combined set of families. We identified three SNPs to be associated with schizophrenia in PDE4D (rs1120303, p = .021), PDE4B (rs7412571, p = .018), and NDEL1 (rs17806986, p = .0038). Greater significance was observed with allelic haplotypes of PDE4D (p = .00084), PDE4B (p = .0022 and p = .029), and NDEL1 (p = .0027) that increased or decreased schizophrenia susceptibility. Our findings with other converging lines of evidence support the underlying importance of DISC1-related molecular pathways in the etiology of schizophrenia and other major mental illnesses. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 16 | Neurosci. Lett. 2009 Jan 449: 228-33 |
| PMID | 19000741 |
| Title | NDE1 and NDEL1: multimerisation, alternate splicing and DISC1 interaction. |
| Abstract | Nuclear Distribution Factor E Homolog 1 (NDE1) and NDE-Like 1 (NDEL1) are highly homologous mammalian proteins. However, whereas NDEL1 is well studied, there is remarkably little known about NDE1. We demonstrate the presence of multiple isoforms of both NDE1 and NDEL1 in the brain, showing that NDE1 binds directly to multiple isoforms of Disrupted in schizophrenia 1 (DISC1), and to itself. We also show that NDE1 can complex with NDEL1. Together these results predict a high degree of complexity of DISC1-mediated regulation of neuronal activity. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 17 | Biochemistry 2009 Aug 48: 7746-55 |
| PMID | 19583211 |
| Title | Oligomer assembly of the C-terminal DISC1 domain (640-854) is controlled by self-association motifs and disease-associated polymorphism S704C. |
| Abstract | Genetic studies have established a role of disrupted-in-schizophrenia-1 (DISC1) in chronic mental diseases (CMD). Limited experimental data are available on the domain structure of the DISC1 protein although multiple interaction partners are known including a self-association domain within the middle part of DISC1 (residues 403-504). The DISC1 C-terminal domain is deleted in the original Scottish pedigree where DISC1 harbors two coiled-coil domains and disease-associated polymorphisms at 607 and 704, as well as the important nuclear distribution element-like 1 (NDEL1) binding site at residues 802-839. Here, we performed mutagenesis studies of the C-terminal domain of the DISC1 protein (residues 640-854) and analyzed the expressed constructs by biochemical and biophysical methods. We identified novel DISC1 self-association motifs and the necessity of their concerted action for orderly assembly: the region 765-854 comprising a coiled-coil domain is a dimerization domain and the region 668-747 an oligomerization domain; dimerization was found to be a prerequisite for orderly assembly of oligomers. Consistent with this, disease-associated polymorphism C704 displayed a slightly higher oligomerization propensity. The heterogeneity of DISC1 multimers in vitro was confirmed with a monoclonal antibody binding exclusively to HMW multimers. We also identified C-terminal DISC1 fragments in human brains, suggesting that C-terminal fragments could carry out DISC1-dependent functions. When the DISC1 C-terminal domain was transiently expressed in cells, it assembled into a range of soluble and insoluble multimers with distinct fractions selectively binding NDEL1, indicating functionality. Our results suggest that assembly of the C-terminal domain is controlled by distinct domains including the disease-associated polymorphism 704 and is functional in vivo. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 18 | Biochem. J. 2010 Apr 427: 69-78 |
| PMID | 20141511 |
| Title | Bioinformatic and experimental survey of 14-3-3-binding sites. |
| Abstract | More than 200 phosphorylated 14-3-3-binding sites in the literature were analysed to define 14-3-3 specificities, identify relevant protein kinases, and give insights into how cellular 14-3-3/phosphoprotein networks work. Mode I RXX(pS/pT)XP motifs dominate, although the +2 proline residue occurs in less than half, and LX(R/K)SX(pS/pT)XP is prominent in plant 14-3-3-binding sites. Proline at +1 is rarely reported, and such motifs did not stand up to experimental reanalysis of human NDEL1. Instead, we discovered that 14-3-3 interacts with two residues that are phosphorylated by basophilic kinases and located in the DISC1 (disrupted-in-schizophrenia 1)-interacting region of NDEL1 that is implicated in cognitive disorders. These data conform with the general findings that there are different subtypes of 14-3-3-binding sites that overlap with the specificities of different basophilic AGC (protein kinase A/protein kinase G/protein kinase C family) and CaMK (Ca2+/calmodulin-dependent protein kinase) protein kinases, and a 14-3-3 dimer often engages with two tandem phosphorylated sites, which is a configuration with special signalling, mechanical and evolutionary properties. Thus 14-3-3 dimers can be digital logic gates that integrate more than one input to generate an action, and coincidence detectors when the two binding sites are phosphorylated by different protein kinases. Paired sites are generally located within disordered regions and/or straddle either side of functional domains, indicating how 14-3-3 dimers modulate the conformations and/or interactions of their targets. Finally, 14-3-3 proteins bind to members of several multi-protein families. Two 14-3-3-binding sites are conserved across the class IIa histone deacetylases, whereas other protein families display differential regulation by 14-3-3s. We speculate that 14-3-3 dimers may have contributed to the evolution of such families, tailoring regulatory inputs to different physiological demands. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 19 | Neuron 2010 Jul 67: 33-48 |
| PMID | 20624590 |
| Title | Dixdc1 is a critical regulator of DISC1 and embryonic cortical development. |
| Abstract | The psychiatric illness risk gene Disrupted in schizophrenia-1 (DISC1) plays an important role in brain development; however, it is unclear how DISC1 is regulated during cortical development. Here, we report that DISC1 is regulated during embryonic neural progenitor proliferation and neuronal migration through an interaction with DIX domain containing-1 (Dixdc1), the third mammalian gene discovered to contain a Disheveled-Axin (DIX) domain. We determined that Dixdc1 functionally interacts with DISC1 to regulate neural progenitor proliferation by co-modulating Wnt-GSK3beta/beta-catenin signaling. However, DISC1 and Dixdc1 do not regulate migration via this pathway. During neuronal migration, we discovered that phosphorylation of Dixdc1 by cyclin-dependent kinase 5 (Cdk5) facilitates its interaction with the DISC1-binding partner NDEL1. Furthermore, Dixdc1 phosphorylation and its interaction with DISC1/NDEL1 in vivo is required for neuronal migration. Together, these data reveal that Dixdc1 integrates DISC1 into Wnt-GSK3beta/beta-catenin-dependent and -independent signaling pathways during cortical development and further delineate how DISC1 contributes to neuropsychiatric disorders. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 20 | Hum. Genet. 2010 Apr 127: 441-52 |
| PMID | 20084519 |
| Title | Evidence of statistical epistasis between DISC1, CIT and NDEL1 impacting risk for schizophrenia: biological validation with functional neuroimaging. |
| Abstract | The etiology of schizophrenia likely involves genetic interactions. DISC1, a promising candidate susceptibility gene, encodes a protein which interacts with many other proteins, including CIT, NDEL1, NDE1, FEZ1 and PAFAH1B1, some of which also have been associated with psychosis. We tested for epistasis between these genes in a schizophrenia case-control study using machine learning algorithms (MLAs: random forest, generalized boosted regression andMonteCarlo logic regression). Convergence of MLAs revealed a subset of seven SNPs that were subjected to 2-SNP interaction modeling using likelihood ratio tests for nested unconditional logistic regression models. Of the 7C2 = 21 interactions, four were significant at the ? = 0.05 level: DISC1 rs1411771-CIT rs10744743 OR = 3.07 (1.37, 6.98) p = 0.007; CIT rs3847960-CIT rs203332 OR = 2.90 (1.45, 5.79) p = 0.003; CIT rs3847960-CIT rs440299 OR = 2.16 (1.04, 4.46) p = 0.038; one survived Bonferroni correction (NDEL1 rs4791707-CIT rs10744743 OR = 4.44 (2.22, 8.88) p = 0.00013). Three of four interactions were validated via functional magnetic resonance imaging (fMRI) in an independent sample of healthy controls; risk associated alleles at both SNPs predicted prefrontal cortical inefficiency during the N-back task, a schizophrenia-linked intermediate biological phenotype: rs3847960-rs440299; rs1411771-rs10744743, rs4791707-rs10744743 (SPM5 p < 0.05, corrected), although we were unable to statistically replicate the interactions in other clinical samples. Interestingly, the CIT SNPs are proximal to exons that encode theDISC1 interaction domain. In addition, the 3' UTR DISC1 rs1411771 is predicted to be an exonic splicing enhancer and the NDEL1 SNP is ~3,000 bp from the exon encoding the region of NDEL1 that interacts with the DISC1 protein, giving a plausible biological basis for epistasis signals validated by fMRI. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 21 | J. Neurosci. 2011 Jun 31: 9043-54 |
| PMID | 21677187 |
| Title | PKA phosphorylation of NDE1 is DISC1/PDE4 dependent and modulates its interaction with LIS1 and NDEL1. |
| Abstract | Nuclear distribution factor E-homolog 1 (NDE1), Lissencephaly 1 (LIS1), and NDE-like 1 (NDEL1) together participate in essential neurodevelopmental processes, including neuronal precursor proliferation and differentiation, neuronal migration, and neurite outgrowth. NDE1/LIS1/NDEL1 interacts with Disrupted in schizophrenia 1 (DISC1) and the cAMP-hydrolyzing enzyme phosphodiesterase 4 (PDE4). DISC1, PDE4, NDE1, and NDEL1 have each been implicated as genetic risk factors for major mental illness. Here, we demonstrate that DISC1 and PDE4 modulate NDE1 phosphorylation by cAMP-dependent protein kinase A (PKA) and identify a novel PKA substrate site on NDE1 at threonine-131 (T131). Homology modeling predicts that phosphorylation at T131 modulates NDE1-LIS1 and NDE1-NDEL1 interactions, which we confirm experimentally. DISC1-PDE4 interaction thus modulates organization of the NDE1/NDEL1/LIS1 complex. T131-phosphorylated NDE1 is present at the postsynaptic density, in proximal axons, within the nucleus, and at the centrosome where it becomes substantially enriched during mitosis. Mutation of the NDE1 T131 site to mimic PKA phosphorylation inhibits neurite outgrowth. Thus PKA-dependent phosphorylation of the NDE1/LIS1/NDEL1 complex is DISC1-PDE4 modulated and likely to regulate its neural functions. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 22 | PLoS ONE 2011 -1 6: e23450 |
| PMID | 21853134 |
| Title | Sequencing of DISC1 pathway genes reveals increased burden of rare missense variants in schizophrenia patients from a northern Swedish population. |
| Abstract | In recent years, DISC1 has emerged as one of the most credible and best supported candidate genes for schizophrenia and related neuropsychiatric disorders. Furthermore, increasing evidence--both genetic and functional--indicates that many of its protein interaction partners are also involved in the development of these diseases. In this study, we applied a pooled sample 454 sequencing strategy, to explore the contribution of genetic variation in DISC1 and 10 of its interaction partners (ATF5, Grb2, FEZ1, LIS-1, PDE4B, NDE1, NDEL1, TRAF3IP1, YWHAE, and ZNF365) to schizophrenia susceptibility in an isolated northern Swedish population. Mutation burden analysis of the identified variants in a population of 486 SZ patients and 514 control individuals, revealed that non-synonymous rare variants with a MAF<0.01 were significantly more present in patients compared to controls (8.64% versus 4.7%, P?=?0.018), providing further evidence for the involvement of DISC1 and some of its interaction partners in psychiatric disorders. This increased burden of rare missense variants was even more striking in a subgroup of early onset patients (12.9% versus 4.7%, P?=?0.0004), highlighting the importance of studying subgroups of patients and identifying endophenotypes. Upon investigation of the potential functional effects associated with the identified missense variants, we found that ?90% of these variants reside in intrinsically disordered protein regions. The observed increase in mutation burden in patients provides further support for the role of the DISC1 pathway in schizophrenia. Furthermore, this study presents the first evidence supporting the involvement of mutations within intrinsically disordered protein regions in the pathogenesis of psychiatric disorders. As many important biological functions depend directly on the disordered state, alteration of this disorder in key pathways may represent an intriguing new disease mechanism for schizophrenia and related neuropsychiatric diseases. Further research into this unexplored domain will be required to elucidate the role of the identified variants in schizophrenia etiology. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 23 | Biochem. Biophys. Res. Commun. 2011 May 408: 707-12 |
| PMID | 21539806 |
| Title | Working memory deficits in neuronal nitric oxide synthase knockout mice: potential impairments in prefrontal cortex mediated cognitive function. |
| Abstract | Neuronal nitric oxide synthase (nNOS) forms nitric oxide (NO), which functions as a signaling molecule via S-nitrosylation of various proteins and regulation of soluble guanylate cyclase (cGC)/cyclic guanosine monophosphate (cGMP) pathway in the central nervous system. nNOS signaling regulates diverse cellular processes during brain development and molecular mechanisms required for higher brain function. Human genetics have identified nNOS and several downstream effectors of nNOS as risk genes for schizophrenia. Besides the disease itself, nNOS has also been associated with prefrontal cortical functioning, including cognition, of which disturbances are a core feature of schizophrenia. Although mice with genetic deletion of nNOS display various behavioral deficits, no studies have investigated prefrontal cortex-associated behaviors. Here, we report that nNOS knockout (KO) mice exhibit hyperactivity and impairments in contextual fear conditioning, results consistent with previous reports. nNOS KO mice also display mild impairments in object recognition memory. Most importantly, we report for the first time working memory deficits, potential impairments in prefrontal cortex mediated cognitive function in nNOS KO mice. Furthermore, we demonstrate Disrupted-in-schizophrenia 1 (DISC1), another genetic risk factor for schizophrenia that plays roles for cortical development and prefrontal cortex functioning, including working memory, is a novel protein binding partner of nNOS in the developing cerebral cortex. Of note, genetic deletion of nNOS appears to increase the binding of DISC1 to NDEL1, regulating neurite outgrowth as previously reported. These results suggest that nNOS KO mice are useful tools in studying the role of nNOS signaling in cortical development and prefrontal cortical functioning. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 24 | Neuron 2011 Nov 72: 559-71 |
| PMID | 22099459 |
| Title | Interaction between FEZ1 and DISC1 in regulation of neuronal development and risk for schizophrenia. |
| Abstract | Disrupted-in schizophrenia 1 (DISC1), a susceptibility gene for major mental disorders, encodes a scaffold protein that has a multifaceted impact on neuronal development. How DISC1 regulates different aspects of neuronal development is not well understood. Here, we show that Fasciculation and Elongation Protein Zeta-1 (FEZ1) interacts with DISC1 to synergistically regulate dendritic growth of newborn neurons in the adult mouse hippocampus, and that this pathway complements a parallel DISC1-NDEL1 interaction that regulates cell positioning and morphogenesis of newborn neurons. Furthermore, genetic association analysis of two independent cohorts of schizophrenia patients and healthy controls reveals an epistatic interaction between FEZ1 and DISC1, but not between FEZ1 and NDEL1, for risk of schizophrenia. Our findings support a model in which DISC1 regulates distinct aspects of neuronal development through its interaction with different intracellular partners and such epistasis may contribute to increased risk for schizophrenia. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 25 | Transl Psychiatry 2011 -1 1: e30 |
| PMID | 22832604 |
| Title | Interactions of human truncated DISC1 proteins: implications for schizophrenia. |
| Abstract | Numerous genetic linkage and association reports have implicated the Disrupted-in-schizophrenia (DISC1) gene in psychiatric illness. The Scottish family translocation, predicted to encode a C-terminus-truncated protein, suggests involvement of short isoforms in the pathophysiology of mental disorders. We recently reported complex alternative splicing patterns for the DISC1 gene and found that short isoforms are overexpressed in the brains of patients with schizophrenia and in carriers of risk-associated alleles. Investigation into the protein-protein interactions of alternative DISC1 isoforms may provide information about the functional consequences of overexpression of truncated forms in mental illness. Human embryonic kidney (HEK293) cells were transiently co-transfected with human epitope-tagged DISC1 variants and epitope-tagged NDEL1, FEZ1, GSK3? and PDE4B constructs. Co-immunoprecipitation assays demonstrated that all truncated DISC1 variants formed complexes with full-length DISC1. Short DISC1 splice variants L?78, L?3 and Esv1 showed reduced or no binding to NDEL1 and PDE4B proteins, but fully interacted with FEZ1 and GSK3?. The temporal expression pattern of GSK3? in the human postmortem tissue across the lifespan closely resembled that of the truncated DISC1 variants, suggesting the possibility of interactions between these proteins in the human brain. Our results suggest that complexes of full-length DISC1 with truncated DISC1 variants may result in cellular disturbances critical to DISC1 function. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 26 | J. Biol. Chem. 2011 Dec 286: 44266-76 |
| PMID | 21998303 |
| Title | Molecular characterization of disrupted in schizophrenia-1 risk variant S704C reveals the formation of altered oligomeric assembly. |
| Abstract | DISC1 (Disrupted in schizophrenia-1) plays essential roles in neuronal proliferation, neuronal migration and axon guidance and has been implicated in schizophrenia and related psychiatric disorders. DISC1 forms a functional complex with nuclear distribution element-like protein-1 (NDEL1), a key component that regulates microtubule organization during cell division and neuronal migration. DISC1 polymorphisms at the binding interface of DISC1-NDEL1 complex have been implicated in schizophrenia. However, it is unknown how schizophrenia risk polymorphisms perturb its interaction with NDEL1 and how they change the inherent biochemical properties of DISC1. Here, we characterize the oligomerization and binding property of DISC1 and its natural schizophrenia risk variant, S704C. Our results show that DISC1 forms octamers via dimers as building blocks and directly interacts with tetramers of NDEL1. The schizophrenia risk variant S704C affects the formation of octamers of DISC1 and exhibits higher-order self-oligomerization. However, the observed formation of new oligomeric species did not influence its binding with NDEL1. These results suggest that the improper oligomeric assembly of DISC1-S704C may underlie the observed phenotypic variation due to the polymorphism. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 27 | Neuropharmacology 2012 Mar 62: 1230-41 |
| PMID | 21195721 |
| Title | DISC1-binding proteins in neural development, signalling and schizophrenia. |
| Abstract | In the decade since Disrupted in schizophrenia 1 (DISC1) was first identified it has become one of the most convincing risk genes for major mental illness. As a multi-functional scaffold protein, DISC1 has multiple identified protein interaction partners that highlight pathologically relevant molecular pathways with potential for pharmaceutical intervention. Amongst these are proteins involved in neuronal migration (e.g. APP, Dixdc1, LIS1, NDE1, NDEL1), neural progenitor proliferation (GSK3?), neurosignalling (Girdin, GSK3?, PDE4) and synaptic function (Kal7, TNIK). Furthermore, emerging evidence of genetic association (NDEL1, PCM1, PDE4B) and copy number variation (NDE1) implicate several DISC1-binding partners as risk factors for schizophrenia in their own right. Thus, a picture begins to emerge of DISC1 as a key hub for multiple critical developmental pathways within the brain, disruption of which can lead to a variety of psychiatric illness phenotypes. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 28 | J. Biol. Chem. 2012 Sep 287: 32381-93 |
| PMID | 22843697 |
| Title | The mitosis and neurodevelopment proteins NDE1 and NDEL1 form dimers, tetramers, and polymers with a folded back structure in solution. |
| Abstract | Paralogs NDE1 (nuclear distribution element 1) and NDEL1 (NDE-like 1) are essential for mitosis and neurodevelopment. Both proteins are predicted to have similar structures, based upon high sequence similarity, and they co-complex in mammalian cells. X-ray diffraction studies and homology modeling suggest that their N-terminal regions (residues 8-167) adopt continuous, extended ?-helical coiled-coil structures, but no experimentally derived information on the structure of their C-terminal regions or the architecture of the full-length proteins is available. In the case of NDE1, no biophysical data exists. Here we characterize the structural architecture of both full-length proteins utilizing negative stain electron microscopy along with our established paradigm of chemical cross-linking followed by tryptic digestion, mass spectrometry, and database searching, which we enhance using isotope labeling for mixed NDE1-NDEL1. We determined that full-length NDE1 forms needle-like dimers and tetramers in solution, similar to crystal structures of NDEL1, as well as chain-like end-to-end polymers. The C-terminal domain of each protein, required for interaction with key protein partners dynein and DISC1 (disrupted-in-schizophrenia 1), includes a predicted disordered region that allows a bent back structure. This facilitates interaction of the C-terminal region with the N-terminal coiled-coil domain and is in agreement with previous results showing N- and C-terminal regions of NDEL1 and NDE1 cooperating in dynein interaction. It sheds light on recently identified mutations in the NDE1 gene that cause truncation of the encoded protein. Additionally, analysis of mixed NDE1-NDEL1 complexes demonstrates that NDE1 and NDEL1 can interact directly. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 29 | J Psychiatr Res 2013 May 47: 657-63 |
| PMID | 23388542 |
| Title | Plasma Ndel1 enzyme activity is reduced in patients with schizophrenia--a potential biomarker? |
| Abstract | NDEL1 oligopeptidase interacts with schizophrenia (SCZ) risk gene product DISC1 and mediates several functions related to neurite outgrowth and neuronal migration. NDEL1 also hydrolyzes neuropeptides previously implicated in SCZ, namely neurotensin and bradykinin. Herein, we compared the plasma NDEL1 enzyme activity of 92 SCZ patients and 96 healthy controls (HCs). NDEL1 enzyme activity was determined by fluorimetric measurements of the FRET peptide substrate Abz-GFSPFRQ-EDDnp hydrolysis rate. A 31% lower mean value for NDEL1 activity was observed in SCZ patients compared to HCs (Student's t = 4.36; p < 0.001; Cohen's d = 0.64). The area under the curve (AUC) for the Receiver Operating Characteristic (ROC) curve for NDEL1 enzyme activity and SCZ/HCs status as outcome was 0.70. Treatment-resistant (TR) SCZ patients were shown to present a significantly lower NDEL1 activity compared to non-TR (NTR) patients by t-test analysis (t = 2.25; p = 0.027). A lower enzymatic activity was significantly associated with both NTR (p = 0.002; B = 1.19; OR = 3.29; CI 95% 1.57-6.88) and TR patients (p < 0.001; B = 2.27; OR = 9.64; CI 95% 4.12-22.54). No correlation between NDEL1 enzyme activity and antipsychotic dose, nicotine dependence, and body mass index was observed. This study is the first to show differences in NDEL1 activity in SCZ patients compared to HCs, besides with a significant lower activity for TR patients compared to NTR patients. Our findings support the NDEL1 enzyme activity implications to clinical practice in terms of diagnosis and drug treatment of SCZ. To compare the NDEL1 enzyme activity levels of schizophrenia (SCZ) patients and healthy controls (HCs) and to correlate these values with the clinical profile and response to treatment by measuring the NDEL1 enzyme activity in human plasma. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 30 | Neuroscience 2014 May 268: 276-83 |
| PMID | 24680936 |
| Title | NDEL1 was decreased in the CA3 region but increased in the hippocampal blood vessel network during the spontaneous seizure period after pilocarpine-induced status epilepticus. |
| Abstract | Nuclear distribution factor E homolog like 1 (NDEL1) plays an important role in mitosis, neuronal migration, and microtubule organization during brain development by binding to disrupted-in-schizophrenia-1 (DISC1) or lissencephaly (LIS1). Although some evidence has suggested that DISC1 expression is altered in epilepsy, few studies have reported the relationship between NDEL1 and the etiology of epilepsy. In present study, we first investigated the expression of NDEL1 and its binding protein DISC1 after pilocarpine-induced epilepsy in male C57BL/6 mice. Data revealed that the mRNA and protein expression of NDEL1 and DISC1 in the whole hippocampus increased during the spontaneous seizure period after status epilepticus (SE). Interestingly, however, the expression of NDEL1 was decreased in the cornu ammonis 3 (CA3) and dentate gyrus (DG) regions. Moreover, SE also increased the number of blood vessels that fed the CA3 and DG regions of the hippocampus and increased the incidence of abnormalities in capillary network formation where NDEL1 protein was expressed positively. Meanwhile, the expression of phosphorylated ERK (p-ERK) was also increased during the spontaneous seizure period, with a similar expression pattern as NDEL1 and DISC1. Based on these results, we hypothesize that NDEL1 might interact with DISC1 to activate ERK signaling and function as a potential protective factor during the spontaneous seizure period after pilocarpine-induced SE. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 31 | PLoS ONE 2014 -1 9: e99892 |
| PMID | 24940743 |
| Title | Expression of DISC1-interactome members correlates with cognitive phenotypes related to schizophrenia. |
| Abstract | Cognitive dysfunction is central to the schizophrenia phenotype. Genetic and functional studies have implicated Disrupted-in-schizophrenia 1 (DISC1), a leading candidate gene for schizophrenia and related psychiatric conditions, in cognitive function. Altered expression of DISC1 and DISC1-interactors has been identified in schizophrenia. Dysregulated expression of DISC1-interactome genes might, therefore, contribute to schizophrenia susceptibility via disruption of molecular systems required for normal cognitive function. Here, the blood RNA expression levels of DISC1 and DISC1-interacting proteins were measured in 63 control subjects. Cognitive function was assessed using neuropsychiatric tests and functional magnetic resonance imaging was used to assess the activity of prefrontal cortical regions during the N-back working memory task, which is abnormal in schizophrenia. Pairwise correlations between gene expression levels and the relationship between gene expression levels and cognitive function and N-back-elicited brain activity were assessed. Finally, the expression levels of DISC1, AKAP9, FEZ1, NDEL1 and PCM1 were compared between 63 controls and 69 schizophrenic subjects. We found that DISC1-interactome genes showed correlated expression in the blood of healthy individuals. The expression levels of several interactome members were correlated with cognitive performance and N-back-elicited activity in the prefrontal cortex. In addition, DISC1 and NDEL1 showed decreased expression in schizophrenic subjects compared to healthy controls. Our findings highlight the importance of the coordinated expression of DISC1-interactome genes for normal cognitive function and suggest that dysregulated DISC1 and NDEL1 expression might, in part, contribute to susceptibility for schizophrenia via disruption of prefrontal cortex-dependent cognitive functions. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 32 | PLoS ONE 2014 -1 9: e99892 |
| PMID | 24940743 |
| Title | Expression of DISC1-interactome members correlates with cognitive phenotypes related to schizophrenia. |
| Abstract | Cognitive dysfunction is central to the schizophrenia phenotype. Genetic and functional studies have implicated Disrupted-in-schizophrenia 1 (DISC1), a leading candidate gene for schizophrenia and related psychiatric conditions, in cognitive function. Altered expression of DISC1 and DISC1-interactors has been identified in schizophrenia. Dysregulated expression of DISC1-interactome genes might, therefore, contribute to schizophrenia susceptibility via disruption of molecular systems required for normal cognitive function. Here, the blood RNA expression levels of DISC1 and DISC1-interacting proteins were measured in 63 control subjects. Cognitive function was assessed using neuropsychiatric tests and functional magnetic resonance imaging was used to assess the activity of prefrontal cortical regions during the N-back working memory task, which is abnormal in schizophrenia. Pairwise correlations between gene expression levels and the relationship between gene expression levels and cognitive function and N-back-elicited brain activity were assessed. Finally, the expression levels of DISC1, AKAP9, FEZ1, NDEL1 and PCM1 were compared between 63 controls and 69 schizophrenic subjects. We found that DISC1-interactome genes showed correlated expression in the blood of healthy individuals. The expression levels of several interactome members were correlated with cognitive performance and N-back-elicited activity in the prefrontal cortex. In addition, DISC1 and NDEL1 showed decreased expression in schizophrenic subjects compared to healthy controls. Our findings highlight the importance of the coordinated expression of DISC1-interactome genes for normal cognitive function and suggest that dysregulated DISC1 and NDEL1 expression might, in part, contribute to susceptibility for schizophrenia via disruption of prefrontal cortex-dependent cognitive functions. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 33 | Mol. Neurobiol. 2015 Oct -1: -1 |
| PMID | 26491028 |
| Title | Depression, Cytokine, and Cytokine by Treatment Interactions Modulate Gene Expression in Antipsychotic Naïve First Episode Psychosis. |
| Abstract | In schizophrenia, genetic and environmental factors affect neurodevelopment and neuroprogressive trajectory. Altered expression of neuro-immune genes and increased levels of cytokines are observed, especially in patients with comorbid depression. However, it remains unclear whether circulating levels of cytokines and expression of these genes are associated, and how antipsychotic treatments impact this association. Relationships between messenger RNA (mRNA) expression of 11 schizophrenia-related genes and circulating levels of cytokines (interleukin (IL)-6, IL-10, and tumor necrosis factor (TNF)-?) were analyzed in 174 antipsychotic naïve first episode psychosis (FEP) and in 77 healthy controls. A subgroup of 72 patients was reassessed after treatment with risperidone. FEP patients were divided into those with and without depression. FEP patients with depression showed increased COMT expression and decreased NDEL1 expression. Increased IL-6 was associated with lowered AKT1 and DROSHA expression, while increased IL-10 was associated with increased NDEL1, DISC1, and MBP expression. IL-6 levels significantly increased the risperidone-induced expression of AKT1, DICER1, DROSHA, and COMT mRNA. The differential mRNA gene expression in FEP is largely associated with increased cytokine levels. While increased IL-6 may downregulate AKT-mediated cellular functions and dysregulate genes involved in microRNA (miRNA) machinery, increased IL-10 has neuroprotective properties. Increased IL-6 levels may prime the expression of genes (AKT1, DICER1, DROSHA, and COMT) in response to risperidone, suggesting that cytokine?×?treatment?×?gene interactions may improve cell function profiles. FEP patients with depression show a different gene expression profile reinforcing the theory that depression in FEP is a different phenotype. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 34 | Mol Neuropsychiatry 2015 Oct 1: 175-190 |
| PMID | 27239468 |
| Title | Copy Number Variations in DISC1 and DISC1-Interacting Partners in Major Mental Illness. |
| Abstract | Robust statistical, genetic and functional evidence supports a role for DISC1 in the aetiology of major mental illness. Furthermore, many of its protein-binding partners show evidence for involvement in the pathophysiology of a range of neurodevelopmental and psychiatric disorders. Copy number variants (CNVs) are suspected to play an important causal role in these disorders. In this study, CNV analysis of DISC1 and its binding partners PAFAH1B1, NDE1, NDEL1, FEZ1, MAP1A, CIT and PDE4B in Scottish and Northern Swedish population-based samples was carried out using multiplex amplicon quantification. Here, we report the finding of rare CNVs in DISC1, NDE1 (together with adjacent genes within the 16p13.11 duplication), NDEL1 (including the overlapping MYH10 gene) and CIT. Our findings provide further evidence for involvement of DISC1 and its interaction partners in neuropsychiatric disorders and also for a role of structural variants in the aetiology of these devastating diseases. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 35 | Eur Neuropsychopharmacol 2015 Dec 25: 2416-25 |
| PMID | 26476704 |
| Title | Increased expression of NDEL1 and MBP genes in the peripheral blood of antipsychotic-naïve patients with first-episode psychosis. |
| Abstract | schizophrenia is a multifactorial neurodevelopmental disorder with high heritability. First-episode psychosis (FEP) is a critical period for determining the disease prognosis and is especially helpful for identifying potential biomarkers associated with the onset and progression of the disorder. We investigated the mRNA expression of 12 schizophrenia-related genes in the blood of antipsychotic-naïve FEP patients (N=73) and healthy controls (N=73). To evaluate the influences of antipsychotic treatment and progression of the disorder, we compared the gene expression within patients before and after two months of treatment with risperidone (N=64). We observed a significantly increased myelin basic protein (MBP) and nuclear distribution protein nudE-like 1 (NDEL1) mRNA levels in FEP patients compared with controls. Comparing FEP before and after risperidone treatment, no significant differences were identified; however; a trend of relatively low NDEL1 expression was observed after risperidone treatment. Animals chronically treated with saline or risperidone exhibited no significant change in NDEL1 expression levels in the blood or the prefrontal cortex (PFC), suggesting that the trend of low NDEL1 expression observed in FEP patients after treatment is likely due to factors other than risperidone treatment (i.e., disease progression). In addition to the recognized association with schizophrenia, MBP and NDEL1 gene products also play an essential role in the functions that are deregulated in schizophrenia, such as neurodevelopment. Our data strengthen the importance of these biological processes in psychotic disorders, indicating that these changes can be detected peripherally and potentially represent putative novel blood biomarkers of susceptibility and disorder progression. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 36 | Neurosci. Res. 2015 Aug 97: 1-6 |
| PMID | 25738396 |
| Title | Half-life of DISC1 protein and its pathological significance under hypoxia stress. |
| Abstract | DISC1 (disrupted in schizophrenia 1) is an intracellular scaffolding molecule which regulates multiple signaling pathways for neural cell differentiation and function. Many biological studies utilizing animal models of DISC1 have indicated that loss of DISC1 functions are associated with pathological psychiatric conditions. Thus, DISC1 protein stability is a prerequisite to its goal in governing neural function, and modulating the protein stability of DISC1 may be a key target for understanding underlying pathology, as well promising drug discovery strategies. Nonetheless, a half-life of DISC1 protein has remained unexplored. Here, we determine for the first time the half-life of DISC1, which are regulated by ubiquitin-proteasome cascade. Overexpression of PDE4B2, a binding partner of DISC1, prolonged the half-life of DISC1, whereas NDEL1 does not alter DISC1 protein stability. Notably, the half-life of DISC1 is diminished under hypoxia stress by increasing protein degradation of DISC1, suggesting that alteration of DISC1 stability may be involved in hypoxia stress-mediated pathological conditions, such as ischemic stroke. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 37 | J. Neurosci. 2015 Feb 35: 2942-58 |
| PMID | 25698733 |
| Title | DBZ regulates cortical cell positioning and neurite development by sustaining the anterograde transport of Lis1 and DISC1 through control of Ndel1 dual-phosphorylation. |
| Abstract | Cell positioning and neuronal network formation are crucial for proper brain function. Disrupted-in-schizophrenia 1 (DISC1) is anterogradely transported to the neurite tips, together with Lis1, and functions in neurite extension via suppression of GSK3? activity. Then, transported Lis1 is retrogradely transported and functions in cell migration. Here, we show that DISC1-binding zinc finger protein (DBZ), together with DISC1, regulates mouse cortical cell positioning and neurite development in vivo. DBZ hindered NDEL1 phosphorylation at threonine 219 and serine 251. DBZ depletion or expression of a double-phosphorylated mimetic form of NDEL1 impaired the transport of Lis1 and DISC1 to the neurite tips and hampered microtubule elongation. Moreover, application of DISC1 or a GSK3? inhibitor rescued the impairments caused by DBZ insufficiency or double-phosphorylated NDEL1 expression. We concluded that DBZ controls cell positioning and neurite development by interfering with NDEL1 from disproportionate phosphorylation, which is critical for appropriate anterograde transport of the DISC1-complex. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 38 | Curr. Protein Pept. Sci. 2015 -1 16: 754-67 |
| PMID | 25961396 |
| Title | Protein-Protein and Peptide-Protein Interactions of NudE-Like 1 (Ndel1): A Protein Involved in Schizophrenia. |
| Abstract | schizophrenia (SCZ) is a devastating chronic mental disease determined by genetic and environmental factors, which susceptibility may involve an impaired neural migration during the neurodevelopmental process. Several candidate risk genes potentially associated with SCZ were related to the formation of protein complexes that ultimately mediate alterations in the neuroplasticity. The most studied SCZ risk gene is the Disrupted-in-schizophrenia 1 (DISC1) gene, which functions seem to depend on the binding with cytoskeleton proteins, as the Nuclear-distribution gene E homolog like-1 (NDEL1) protein among others. Interestingly, NDEL1 is the only binding partner of DISC1 proteins with oligopeptidase activity, besides playing roles in multiple processes, including cytoskeletal organization, cell signaling, neuron migration, and neurite outgrowth. It is still not clear if the protein-protein interaction between NDEL1 and DISC1 is enough to explain all cellular functions attributed to these proteins, but there are several lines of evidence suggesting the importance of the catalytic activity of NDEL1 for the neurite outgrowth and neuron migration during embryogenesis. Recent works of the group have demonstrated the modulation of NDEL1 activity by DISC1, which is hypothetically impaired in SCZ patients. In fact, more recently, we also showed a lower NDEL1 activity in the plasma of SCZ patients compared to control health subjects, but the physiopathological significance of this feature is still unknown. Here we discuss NDEL1 ligands involved in protein-protein complex formations related to neurodevelopmental diseases, as (1) lissencephaly or Miller-Dieker Syndrome (MDS), which is characterized by the typical craniofacial features and abnormal smooth cerebral surface, and as (2) SCZ, since they both seem to be determined by defects in neuronal migration. Although impaired lissencephaly protein Lis1 complex formation with NDEL1 is the leading cause of lissencephaly, this binding does not affect NDEL1 oligopeptidase activity. On the other hand, although MDS and SCZ may be both determined by an abnormal neuronal migration, DISC1 complex formation with NDEL1 was shown to inhibit NDEL1 activity. Also differently of MDS, SCZ needs inputs from environmental factors, while lissencephaly is not likely dependent or affected by the environment. Several other proteins and peptide ligands were described for NDEL1, Lis1 and DISC1, thanks to the employment of biochemical, immunochemical, and biological (using cells or living animals) assays, including heterologous expression and also simply by purification from nature of these proteins in the complex form. Effects of the post-translational modifications of these proteins are also discussed here. Taken together, the data presented here show in essence how protein-protein and proteinpeptide interactions can underlie fundamental processes as cell division, maturation and migration, necessary for adequate formation of a complex structured tissue as the brain. A special attention was given to NDEL1 as this protein binds to either proteins or peptides, besides having proteolytic activity. Moreover, NDEL1 seems to be the key protein underlying two seemingly unrelated diseases with highly complex etiology, as lissencephaly and SCZ. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |
| 39 | Schizophr. Res. 2016 Apr 172: 60-7 |
| PMID | 26851141 |
| Title | Genome-wide investigation of schizophrenia associated plasma Ndel1 enzyme activity. |
| Abstract | NDEL1 is a DISC1-interacting oligopeptidase that cleaves in vitro neuropeptides as neurotensin and bradykinin, and which has been associated with both neuronal migration and neurite outgrowth. We previously reported that plasma NDEL1 enzyme activity is lower in patients with schizophrenia (SCZ) compared to healthy controls (HCs). To our knowledge, no previous study has investigated the genetic factors associated with the plasma NDEL1 enzyme activity. In the current analyses, samples from 83 SCZ patients and 92 control subjects that were assayed for plasma NDEL1 enzyme activity were genotyped on Illumina Omni Express arrays. A genetic relationship matrix using genome-wide information was then used for ancestry correction, and association statistics were calculated genome-wide. NDEL1 enzyme activity was significantly lower in patients with SCZ (t=4.9; p<0.001) and was found to be associated with CAMK1D, MAGI2, CCDC25, and GABGR3, at a level of suggestive significance (p<10(-6)), independent of the clinical status. Then, we performed a model to investigate the observed differences for case/control measures. 2 SNPs at region 1p22.2 reached the p<10(-7) level. ZFPM2 and MAD1L1 were the only two genes with more than one hit at 10(-6) order of p value. Therefore, NDEL1 enzyme activity is a complex trait influenced by many different genetic variants that may contribute to SCZ physiopathology. |
| SCZ Keywords | schizophrenia, schizophrenic, schizophrenics |