Platelet-Derived Growth Factor B Type Receptor

Abstract

Platelet-derived growth factor (PDGF) is a major mitogen in serum for connective tissue cells (for reviews, see Heldin et al., 1985; Ross et al., 1986). The in vivo function of PDGF is not known. However, the fact that PDGF is released from platelets in conjunction with the blood coagulation and stimulates not only proliferation, but also chemotaxis and synthesis of matrix proteins of connective tissue cells, is compatible with a function for PDGF in wound healing (Heldin et a1.,1985; Ross et al., 1986). The fact that PDGF is expressed in the placenta also suggests a role for PDGF during the development (Goustin et al., 1985). In addition, PDGF has been found to be produced by type-1 astrocytes and to act on O-2A progenitor cells that differentiate to oligodendrocytes and type-2 astrocytes, suggesting a role for PDGF in the developing rat brain (Richardson et al., 1988; Noble et al., 1988). PDGF may also have adverse effects in several conditions involving cell proliferation, such as atherosclerosis, various fibrotic conditions, as well as malignant diseases (Heldin et al., 1985; Ross et al., 1986). The latter possibility is illustrated by the fact that PDGF is homologous to p28^sis, the transforming protein of simian sarcoma virus (Waterfield et al., 1983; Doolittle et al., 1983).