57142

RTN4

ASY|NI220/250|NOGO|NOGO-A|NOGOC|NSP|NSP-CL|Nbla00271|Nbla10545|Nogo-B|Nogo-C|RTN-X|RTN4-A|RTN4-B1|RTN4-B2|RTN4-C;reticulon 4;RTN4;reticulon 4

Human NogoA|My043 protein|foocen|neurite growth inhibitor 220|neurite outgrowth inhibitor|neuroendocrine-specific protein C homolog|reticulon 5|reticulon-4

2p16.3

protein-coding

OBJECTS: Neurite outgrowth inhibitor proteins (Nogos) comprise a family of three major members and are characterized by a conserved RHD domain. Among all the members, Nogo-B was identified to be significantly elevated and to play an important role in liver cirrhosis while Nogo-C was the shortest one and received little attention. The aim of this study is to investigate the relevance and mechanism of Nogo-C involved in Hepatocellular carcinoma (HCC). METHODS: The expression of Nogo-C in paired HCC specimens was measured with quantitative RT-PCR. The function of Nogo-C over expressing in SMMC-7721 and WRL-68 HCC cell lines were estimated through cell proliferation assay and colony formation assay. A proteome-wide identification of Nogo-C-binding proteins was performed using affinity purification combined with a highly sensitive mass spectrometric technique. The protein interactions were confirmed using co-IP and immunofluorescence confocal assays. RESULTS: Compared with the neighboring pathologically normal tissues, the expression of Nogo-C mRNA was extremely down-regulated in HCC specimens and was significantly related to greater tumor size and worse prognosis. Overexpression of Nogo-C in HCC cell lines resulted in an inhibition of cell growth. A total of 73 proteins were detected and considered in association with Nogo-C, among which B-raf and Nogo-B were validated. CONCLUSION: We identify Nogo-C as a tumor suppressor gene in HCC and B-raf as a novel interacting protein. These findings provide new directions for the mechanism research of Nogo family.