title: Dominant-negative mutations of platelet-derived growth factor (PDGF) receptors. Inhibition of receptor function by ligand-dependent formation of heterodimers between PDGF alpha- and beta-receptors.
abstract: We showed previously that a truncated form of the platelet-derived growth factor (PDGF) beta-receptor lacking its kinase region can form a nonfunctional heterodimer with the wild-type beta-receptor and thereby inhibit its signal transduction. In this paper we investigated whether the truncated form of either alpha- or beta-receptor could block the function of the other type of wild-type PDGF receptor. When the truncated alpha-receptor was expressed in Xenopus oocytes in excess over either the wild-type alpha- or beta-receptor, the Ca2+ mobilization signal elicited by either the wild-type alpha- or beta-receptor was completely blocked. The truncated beta-receptor abolished signaling by the wild-type alpha-receptor in response to PDGF-AB or -BB. However signal transduction by the alpha-receptor in response to PDGF-AA was not affected by the truncated beta-receptor. In the presence of PDGF-AB or -BB, both the wild-type and truncated beta-receptors formed a heterologous complex with the alpha-receptor in intact cells. A kinase-inactive beta-receptor (an ATP-binding site mutation) became cross-phosphorylated on tyrosine residues by the co-expressed wild-type alpha-receptor in response to PDGF-AB or -BB but not in response to PDGF-AA. These findings indicate that the alpha-and beta-receptors interact in response to PDGF-AB or -BB and are consistent with the hypothesis that the truncated alpha-receptor inhibits function of the wild-type beta-receptor through formation of a ligand-dependent nonfunctional alpha beta-heterodimer. A similar heterodimer can form between the truncated beta-receptor and the wild-type alpha-receptor. These observations provide useful information for future studies using dominant-negative mutations of PDGF receptors to selectively inhibit the actions of specific PDGFs in animals.
authors.affiliation: Department of Medicine, Howard Hughes Medical Institute, University of California San Francisco 94143-0130.
authors.forename: H
authors.initials: H
authors.lastname: Ueno
authors.forename: J A
authors.initials: JA
authors.lastname: Escobedo
authors.forename: L T
authors.initials: LT
authors.lastname: Williams
mesh_terms: D000818:Animals; D000077214:Becaplermin; D002118:Calcium / Q000378:metabolism; D005260:Female; D017353:Gene Deletion; D015870:Gene Expression; D015723:Gene Library; D005799:Genes, Dominant; D006801:Humans; D051379:Mice; D016296:Mutagenesis; D009865:Oocytes / Q000378:metabolism; D010766:Phosphorylation; D010920:Placenta / Q000378:metabolism; D010982:Platelet-Derived Growth Factor / Q000378:metabolism / Q000494:pharmacology; D011247:Pregnancy; D020574:Proto-Oncogene Proteins c-sis; D012333:RNA, Messenger / Q000378:metabolism; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism; D017479:Receptors, Platelet-Derived Growth Factor / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism / Q000494:pharmacology; D014981:Xenopus
chemical_list: D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D012333:RNA, Messenger; D011994:Recombinant Proteins; D000077214:Becaplermin; D020794:Receptor Protein-Tyrosine Kinases; D017479:Receptors, Platelet-Derived Growth Factor; D002118:Calcium