Ligand stimulation reduces platelet-derived growth factor beta-receptor susceptibility to tyrosine dephosphorylation
2001 (English)In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 276, no 30, 27749-27752 p.Article in journal (Refereed) Published
Ligand binding to the platelet-derived growth factor (PDGF) beta-receptor leads to increased receptor tyrosine phosphorylation as a consequence of dimerization-induced activation of the intrinsic receptor tyrosine kinase activity. In this study we asked whether ligand-stimulated PDGF beta-receptor tyrosine phosphorylation, to some extent, also involved reduced susceptibility to tyrosine dephosphorylation. To investigate this possibility we compared the sensitivity of ligand-stimulated and non-stimulated forms of tyrosine-phosphorylated PDGF beta-receptors to dephosphorylation using various preparations containing protein-tyrosine phosphatase activity. Ligand-stimulated or unstimulated tyrosine-phosphorylated receptors were obtained after incubation of cells with pervanadate only or pervanadate, together with PDGF-BB, respectively. Dephosphorylation of receptors immobilized on wheat germ agglutinin-Sepharose, as well as of receptors in intact cell membranes, was investigated under conditions when rephosphorylation did not occur. As compared with unstimulated receptors the ligand-stimulated PDGF beta-receptors showed about 10-fold reduced sensitivity to dephosphorylation by cell membranes, a recombinant form of the catalytic domain of density-enhanced phosphatase-1, or recombinant protein-tyrosine phosphatase 1B. We conclude that ligand-stimulated forms of the PDGF beta-receptor display a reduced susceptibility to dephosphorylation. Our findings suggest a novel mechanism whereby ligand stimulation of PDGF beta-receptor, and possibly other tyrosine kinase receptors, leads to a net increase in receptor tyrosine phosphorylation.
Place, publisher, year, edition, pages
The American Society for Biochemistry and Molecular Biology, Inc. , 2001. Vol. 276, no 30, 27749-27752 p.
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:uu:diva-90184DOI: 10.1074/jbc.C100286200PubMedID: 11390370OAI: oai:DiVA.org:uu-90184DiVA: diva2:162449