Differential requirement of a motif within the carboxyl-terminal domain of alpha-platelet-derived growth factor (alpha PDGF) receptor for PDGF focus forming activity chemotaxis, or growth.
To determine the molecular basis for the transforming function of platelet-derived growth factor (PDGF)-A in NIH/3T3 cells, we have constructed chimerae consisting of the extracellular domain of the human CSF-1R (fms) linked to the cytoplasmic domain of the alpha PDGF receptor (alpha R) containing a series of deletion or point mutations. The ability of fms/alpha R chimerae to mediate CSF-1-dependent anchorage-independent growth, focus formation, and chemotaxis of NIH/3T3 cells was then examined. Our results provide evidence that a domain encompassing amino acid residues 977-1024 of the alpha PDGFR is required for ligand-dependent focus formation, but not chemotaxis or anchorage-independent growth, and that tyrosine residues within this domain constitute the major binding site for phospholipase C gamma. Therefore, our findings suggest that: (i) the focus forming function of alpha PDGFR correlates well with the ability of the receptor to bind phospholipase C gamma, and (ii) the mechanism of focus formation mediated by alpha PDGFR may be distinguished from that required for chemotaxis or anchorage-independent growth.
Yu
J C
JC
Laboratory of Cellular and Molecular Biology, NCI, National Institutes of Health, Bethesda, Maryland 20892, USA.
Li
W
W
Wang
L M
LM
Uren
A
A
Pierce
J H
JH
Heidaran
M A
MA
D016475:3T3 Cells; D000818:Animals; D001665:Binding Sites; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002633:Chemotaxis / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D016173:Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D051379:Mice; D016297:Mutagenesis, Site-Directed; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D017354:Point Mutation; D016186:Receptor, Macrophage Colony-Stimulating Factor / Q000096:biosynthesis / Q000502:physiology*; D020796:Receptor, Platelet-Derived Growth Factor alpha; D017479:Receptors, Platelet-Derived Growth Factor / Q000096:biosynthesis / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism / Q000494:pharmacology; D017384:Sequence Deletion; D014162:Transfection; D010738:Type C Phospholipases / Q000378:metabolism
D010982:Platelet-Derived Growth Factor; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D016173:Macrophage Colony-Stimulating Factor; D016186:Receptor, Macrophage Colony-Stimulating Factor; D020796:Receptor, Platelet-Derived Growth Factor alpha; D017479:Receptors, Platelet-Derived Growth Factor; D010738:Type C Phospholipases