Independent expression of human alpha or beta platelet-derived growth factor receptor cDNAs in a naive hematopoietic cell leads to functional coupling with mitogenic and chemotactic signaling pathways.

Abstract

Distinct genes encode a and f3 plateletderived growth factor (PDGF) receptors that differ in their abilities to be triggered by three dimeric forms of the PDGF molecule. We show that PDGF-receptor mitogenic function can be reconstituted in a naive hematopoietic cell line by introduction of expression vectors for either a or j3 PDGF receptor cDNAs. Thus, each receptor is independently capable of coupling with mitogenic signal-transduction pathways inherently present in these cells. Activation of either receptor also resulted in chemotaxis, alterations in inositol lipid metabolism, and mobilization of intracellular Ca2+. The magnitude of these functional responses correlated well with the binding properties of the different PDGF isoforms to each receptor. Thus, availability of specific PDGF isoforms and relative expression of each PDGF-receptor gene product are major determinants of the spectrum of known PDGF responses.

Identification of Tyr-762 in the platelet-derived growth factor α-receptor as the binding site for Crk proteins

“…While both PDGF a-and b-receptors are able to initiate DNA synthesis (Hosang et al, 1989;Matsui et al, 1989), it has been reported that the breceptor is a more potent mediator of mitogenicity compared to the a-receptor in certain cell types (Heidaran et al, 1993;Inui et al, 1994). Moreover, whereas the b-receptor mediates stimulation of chemotaxis, a-receptor inhibits chemotaxis, at least in certain cell types (Eriksson et al, 1992;Koyama et al, 1992;Siegbahn et al, 1990).…”

Substrates modified by advanced glycation end-products cause dysfunction and death in retinal pericytes by reducing survival signals mediated by platelet-derived growth factor

“…PDGF is a multifunctional dimeric peptide occurring as either AA, BB homodimers or AB heterodimer isoforms. These dimeric configurations differentially activate the a or b subunits of the PDGF tyrosine kinase receptor and ligand binding studies have shown that the α-subunit binds either the A or B chain, and the β-subunit binds only the B chain [22,23]. These ligand/receptor combinations account for a wide range of PDGF-mediated effects in a range of cell types.…”

Deletion or substitution within the alpha platelet-derived growth factor receptor kinase insert domain: effects on functional coupling with intracellular signaling pathways.

“…PDGF-BB was labeled by the method of Bolton and Hunter (specific activity, 2 x 104 cpm/ng) (2). 125I-PDGF-BB binding to cells was performed as previously described (28 For mitogenic assays, 32D transfectants were washed twice with phosphate-buffered saline (PBS) and plated at 3 x 105 cells per ml into Costar 24-well plates in RPMI 1640 medium containing 15% fetal calf serum with or without various concentration of PDGF-BB or murine IL-3 (Genzyme) as previously described (29). For the soft-agar assay, cells were plated At 10-fold serial dilutions in semisolid agarose medium containing RPMI 1640 medium supplemented with 15% fetal calf serum and 0.45% SeaPlaque agarose (FMC Corp.).…”

“…Colony formation was scored at 14 days. For determination of directed cell migration in response to PDGF-BB, modified Boyden chambers and Nuclepore filters (pore size, 5 ,um) were used as described previously (17,29).…”

“…Mitogenic and chemotactic signaling pathways inherently expressed by these cells could be efficiently coupled by introduction of either aPDGFR or 3PDGFR and triggering by the appropriate PDGF ligand (29). This system provided the opportunity to systematically compare the effects of progressive deletions in the ki of the aPDGFR on distinct responses mediated by this receptor.…”