Differential interaction of CrkII adaptor protein with platelet-derived growth factor alpha- and beta-receptors is determined by its internal tyrosine phosphorylation.

CrkII is an intracellular adaptor protein involved in signal transduction by various growth factors. Activation of PDGF alpha-receptor resulted in its association with CrkII in vivo. In contrast, binding of CrkII to the PDGF beta-receptor was negligible, despite its becoming prominently phosphorylated. Bacterially expressed GST-CrkII SH2 domain specifically bound to ...
Tyr-762 and Tyr-771 in the activated PDGF alpha- and beta- receptors, respectively. GST fusion protein of full-length CrkII also bound to the activated PDGF beta-receptor. However, tyrosine phosphorylation of GST-CrkII diminished its binding to the beta-receptor. CrkI, a truncated version of CrkII lacking the phosphorylatable tyrosine residue, could bind to both PDGF alpha- and beta-receptors in vivo. In conclusion, tyrosine phosphorylation of CrkII negatively affects its binding to the PDGF receptors. The differential binding of CrkII to the PDGF alpha- and beta- receptors may be a rationale for functional diversity between the two receptors.
Mesh Terms:
Animals, Models, Biological, Phosphorylation, Platelet-Derived Growth Factor, Protein Binding, Protein Kinases, Proto-Oncogene Proteins, Proto-Oncogene Proteins c-crk, Receptor, Platelet-Derived Growth Factor alpha, Receptor, Platelet-Derived Growth Factor beta, Recombinant Fusion Proteins, Signal Transduction, Swine, Tyrosine, src Homology Domains
Biochem. Biophys. Res. Commun.
Date: Apr. 02, 2000
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