Src Homology 3 Binding Sites in the P2Y2Nucleotide Receptor Interact with Src and Regulate Activities of Src, Proline-rich Tyrosine Kinase 2, and Growth Factor Receptors
Many G protein-coupled receptors activate growth factor receptors, although the mechanisms controlling this transactivation are unclear. We have identified two proline-rich, SH3 binding sites (PXXP) in the carboxyl-terminal tail of the human P2Y2 nucleotide receptor that directly associate with the tyrosine kinase Src in protein binding assays. Furthermore, Src co-precipitated with the P2Y2 receptor in 1321N1 astrocytoma cells stimulated with the P2Y2 receptor agonist UTP. A mutant P2Y2 receptor lacking the PXXP motifs was found to stimulate calcium mobilization and serine/threonine phosphorylation of the Erk1/2 mitogen-activated protein kinases, like the wild-type receptor, but was defective in its ability to stimulate tyrosine phosphorylation of Src and Src-dependent tyrosine phosphorylation of the proline-rich tyrosine kinase 2, epidermal growth factor receptor (EGFR), and platelet-derived growth factor receptor. Dual immunofluorescence labeling of the P2Y2 receptor and the EGFR indicated that UTP caused an increase in the co-localization of these receptors in the plasma membrane that was prevented by the Src inhibitor PP2. Together, these data suggest that agonist-induced binding of Src to the SH3 binding sites in the P2Y2 receptor facilitates Src activation, which recruits the EGFR into a protein complex with the P2Y2 receptor and allows Src to efficiently phosphorylate the EGFR.
Liu, Jun, Zhongji Liao, Jean Camden, Korey D. Griffin, Richard C. Garrad, Laura I. Santiago-Pérez, Fernando A. González, Cheikh I. Seye, Gary A. Weisman, and Laurie Erb. "Src homology 3 binding sites in the P2Y2 nucleotide receptor interact with Src and regulate activities of Src, proline-rich tyrosine kinase 2, and growth factor receptors." Journal of Biological Chemistry 279, no. 9 (2004): 8212-8218.
Journal of Biological Chemistry 279