Ligand-induced polyubiquitination of the platelet-derived growth factor beta-receptor.
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Mori S, Heldin CH, Claesson-Welsh L
Ligand-induced polyubiquitination of the platelet-derived growth factor beta-receptor.
J Biol Chem. 1992 Mar 25;267(9):6429-34.
- PubMed ID
- 1313434 [ View in PubMed]
- Abstract
We have analyzed the nature of ligand-induced shift to higher molecular weight forms of the beta-receptor for platelet-derived growth factor expressed in porcine aortic endothelial cells. The modification of the beta-receptor was found to be due to polyubiquitination, as judged by immunoblotting using an anti-ubiquitin antiserum. A mutant beta-receptor made kinase negative by a point mutation (K634A mutant) did not undergo ubiquitination in response to ligand stimulation. A mutant in which carboxyl-terminal 98 amino acids were deleted (CT98 mutant) and which retained kinase activity was likewise not ubiquitinated. These data suggest that the kinase activity, as well as the carboxyl-terminal 98 amino acids, is required for ubiquitination of the beta-receptor. Ligand-induced degradation of the receptor-bound ligand, as well as of the receptor itself, was partially impaired in the CT98-receptor-expressing cells, suggesting that the ubiquitination is of importance for efficient degradation of the ligand-receptor complex.