Cloning, expression, characterization, and role in autocrine cell growth of cell surface retention sequence binding protein-1.
Cell surface retention sequence binding protein-1 (CRSBP-1) is a cell surface binding protein for the cell surface retention sequence (CRS) motif of the v-sis gene product (platelet-derived growth factor-BB). It has been shown to be responsible for cell surface retention of the v-sis gene product in v-sis-transformed cells (fibroblasts) and has been hypothesized to play a role in autocrine growth and transformation of these cells. Here we demonstrate that the CRSBP-1 cDNA cloned from bovine liver libraries encodes a 322-residue type I membrane protein containing a 23-residue signal peptide, a 215-residue cell surface domain, a 21-residue transmembrane domain, and a 63-residue cytoplasmic domain. CRSBP-1 expressed in transfected cells is an approximately 120-kDa disulfide-linked homodimeric glycoprotein and exhibits dual ligand (CRS-containing growth regulators (v-sis gene product and insulin-like growth factor binding protein-3, IGFBP-3) and hyaluronic acid) binding activity. CRSBP-1 overexpression (by stable transfection of cells with CRSBP-1 cDNA) enhances autocrine loop signaling, cell growth, and tumorigenicity (in mice) of v-sis-transformed cells. CRSBP-1 expression also enhances autocrine cell growth mediated by IGFBP-3 in human lung carcinoma cells (H1299 cells), which express very little, if any, endogenous CRSBP-1 and exhibits a mitogenic response to exogenous IGFBP-3, stably transfected with IGFBP-3 cDNA. However, CRSBP-1 overexpression does not affect growth of normal and transformed cells that do not produce these CRS-containing growth regulators. These results suggest that CRSBP-1 plays a role in autocrine regulation of cell growth mediated by growth regulators containing CRS.
Huang
Shuan Shian
SS
Departments of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, Missouri 63104, USA. huangjs@slu.edu
Tang
Fen-Mei
FM
Huang
Yen-Hua
YH
Liu
I-Hua
IH
Hsu
Shih-Chi
SC
Chen
Shui-Tein
ST
Huang
Jung San
JS
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D002417:Cattle; D002455:Cell Division; D002461:Cell Line, Transformed; D045744:Cell Line, Tumor; D003593:Cytoplasm / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D003902:Detergents / Q000494:pharmacology; D019281:Dimerization; D004220:Disulfides / Q000737:chemistry; D005347:Fibroblasts / Q000378:metabolism; D015723:Gene Library; D006023:Glycoproteins / Q000737:chemistry; D006801:Humans; D015151:Immunoblotting; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008565:Membrane Proteins / Q000096:biosynthesis* / Q000235:genetics* / Q000502:physiology; D051379:Mice; D008969:Molecular Sequence Data; D041681:NIH 3T3 Cells; D017830:Octoxynol / Q000494:pharmacology; D020575:Oncogene Proteins v-sis / Q000378:metabolism; D010455:Peptides / Q000737:chemistry; D011485:Protein Binding; D021382:Protein Sorting Signals; D017386:Sequence Homology, Amino Acid; D013997:Time Factors; D014162:Transfection
D018076:DNA, Complementary; D003902:Detergents; D004220:Disulfides; D006023:Glycoproteins; D018972:Insulin-Like Growth Factor Binding Protein 3; D008565:Membrane Proteins; D020575:Oncogene Proteins v-sis; D010455:Peptides; D021382:Protein Sorting Signals; C091632:cell-surface retention-binding protein 1; D017830:Octoxynol