347252

IGFBPL1

IGFBP-RP4|bA113O24.1;insulin-like growth factor binding protein-like 1;IGFBPL1;insulin-like growth factor binding protein-like 1

IGFBP-related protein 10|insulin-like growth factor binding protein related protein 4|insulin-like growth factor-binding protein-like 1|insulin-like growth factor-binding-related protein 4

9p13.1

protein-coding

Count: 1; Generif

Here we report the identification of a new insulin-like growth factor binding protein homologue, provisionally designated insulin-like growth factor binding related protein-4 (IGFBP-rP4). IGFBP-rP4 was found to be most closely related to IGFBP-7 with 52% amino acid homology and 43% amino acid identity, and shares a similar domain structure. Semi-quantitative RT-PCR expression analysis demonstrated a pattern of downregulation of this gene in multiple tumor samples including lung and colon cancer, compared to matched adjacent normal tissue. Western blotting revealed a protein of approximately 38kDa expressed in both the cell pellet and secreted into the supernatant of transiently transfected Cos-7 cells. Cos-7 supernatants containing IGFBP-RP4 protein were observed to suppress the growth of HeLa cells in culture compared to vector controls. IGFBP-RP4 directly transiently transfected into HeLa cells also further confirmed the growth suppressive properties of this protein. Together these data suggest that IGFBP-RP4 may be a novel putative tumor suppressor protein.