title: Cell surface retention sequence binding protein-1 interacts with the v-sis gene product and platelet-derived growth factor beta-type receptor in simian sarcoma virus-transformed cells.
abstract: The cell surface retention sequence (CRS) binding protein-1 (CRSBP-1) is a newly identified membrane glycoprotein which is hypothesized to be responsible for cell surface retention of the oncogene v-sis and c-sis gene products and other secretory proteins containing CRSs. In simian sarcoma virus-transformed NIH 3T3 cells (SSV-NIH 3T3 cells), a fraction of CRSBP-1 was demonstrated at the cell surface and underwent internalization/recycling as revealed by cell surface 125I labeling and its resistance/sensitivity to trypsin digestion. However, the majority of CRSBP-1 was localized in intracellular compartments as evidenced by the resistance of most of the 35S-metabolically labeled CRSBP-1 to trypsin digestion, and by indirect immunofluorescent staining. CRSBP-1 appeared to form complexes with proteolytically processed forms (generated at and/or after the trans-Golgi network) of the v-sis gene product and with a approximately 140-kDa proteolytically cleaved form of the platelet-derived growth factor (PDGF) beta-type receptor, as demonstrated by metabolic labeling and co-immunoprecipitation. CRSBP-1, like the v-sis gene product and PDGF beta-type receptor, underwent rapid turnover which was blocked in the presence of 100 microM suramin. In normal and other transformed NIH 3T3 cells, CRSBP-1 was relatively stable and did not undergo rapid turnover and internalization/recycling at the cell surface. These results suggest that in SSV-NIH 3T3 cells, CRSBP-1 interacts with and forms ternary and binary complexes with the newly synthesized v-sis gene product and PDGF beta-type receptor at the trans-Golgi network and that the stable binary (CRSBP-1.v-sis gene product) complex is transported to the cell surface where it presents the v-sis gene product to unoccupied PDGF beta-type receptors during internalization/recycling.
authors: Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, St. Louis, Missouri 63104, USA.
authors: C
authors: C
authors: Boensch
authors: S S
authors: SS
authors: Huang
authors: D T
authors: DT
authors: Connolly
authors: J S
authors: JS
authors: Huang
mesh_terms: D016475:3T3 Cells; D000818:Animals; D002472:Cell Transformation, Viral; D019084:Fluorescent Antibody Technique, Indirect; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D020575:Oncogene Proteins v-sis; D011817:Rabbits; D020797:Receptor, Platelet-Derived Growth Factor beta; D017479:Receptors, Platelet-Derived Growth Factor / Q000378:metabolism*; D015682:Retroviridae Proteins, Oncogenic / Q000378:metabolism*; D012842:Sarcoma Virus, Woolly Monkey / Q000378:metabolism*; D013498:Suramin / Q000378:metabolism; D013499:Surface Properties; D014357:Trypsin / Q000378:metabolism
chemical_list: D008565:Membrane Proteins; D020575:Oncogene Proteins v-sis; D015682:Retroviridae Proteins, Oncogenic; C091632:cell-surface retention-binding protein 1; D013498:Suramin; D020797:Receptor, Platelet-Derived Growth Factor beta; D017479:Receptors, Platelet-Derived Growth Factor; D014357:Trypsin