Detection of PDGF-2 homodimers in human tumor cells.

摘要: The v-sis oncogene encodes a protein structurally and functionally related to human platelet-derived growth factor (PDGF). In the present studies, we show that primary translational product of sis proto-oncogene is 26-kd protein, p26c-sis. This processed yield disulfide-linked homodimer, p56c-sis, which further 35,000-dalton dimer, p35c-sis. Like gene product, PDGF-2 precursor undergoes N-linked glycosylation, implying its processing through endoplasmic reticulum. was shown possess functional properties PDGF. Whereas lysates control COS-1 cells lacked mitogenic activity, transfected with c-sis/PDGF-2 expression vector specifically stimulated DNA synthesis quiescent fibroblasts. Moreover, this activity completely inhibitable by PDGF antibody. Identical forms sis/PDGF-2 were identified in tumor expressed transcripts. These proteins be associated membrane component not detectably secreted into culture medium. findings support concept responsive proliferative actions can an important step processes leading malignancy.