Recruitment of the protein-tyrosine phosphatase SHP-2 to the C-terminal tyrosine of the prolactin receptor and to the adaptor protein Gab2.
The protein-tyrosine phosphatase SHP-2 modulates signaling events through receptor tyrosine kinases and cytokine receptors including the receptor for prolactin (PRLR). Here we investigated mechanisms of SHP-2 recruitment within the PRLR signaling complex. Using SHP-2 and PRLR immunoprecipitation studies in 293 cells and in the mouse mammary epithelial cell line HC11, we found that SHP-2 co-immunoprecipitates with the PRLR and that the C-terminal tyrosine of the PRLR plays a regulatory role in both the tyrosine phosphorylation and the recruitment of SHP-2. Our results further indicate that SHP-2 association to the PRLR occurs via the C-terminal SH2 domain of the phosphatase. In addition, we determined that the newly identified adaptor protein Gab2, but not Gab1, is specifically tyrosine phosphorylated and is able to recruit SHP-2 and phosphatidyinositol 3-kinase in response to PRLR activation. Together, these studies suggest the presence of dual recruitment sites for SHP-2; the first is to the C-terminal tyrosine of the PRLR and the second is to the adaptor protein Gab2.
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Department of Medicine, Division of Hematology and Molecular Oncology Group, Royal Victoria Hospital, McGill University, Montreal, Quebec H3A 1A1, Canada.
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D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D001665:Binding Sites; D015153:Blotting, Western; D001940:Breast / Q000378:metabolism; D002460:Cell Line; D004848:Epithelium / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010750:Phosphoproteins / Q000737:chemistry / Q000378:metabolism*; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011388:Prolactin / Q000494:pharmacology; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000737:chemistry / Q000378:metabolism*; D011981:Receptors, Prolactin / Q000737:chemistry / Q000378:metabolism*; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases; D015398:Signal Transduction; D013997:Time Factors; D014162:Transfection; D014443:Tyrosine / Q000378:metabolism*
D048868:Adaptor Proteins, Signal Transducing; C490895:GAB2 protein, human; C490894:Gab2 protein, mouse; D047908:Intracellular Signaling Peptides and Proteins; D010750:Phosphoproteins; D011981:Receptors, Prolactin; D014443:Tyrosine; D011388:Prolactin; D019869:Phosphatidylinositol 3-Kinases; C516724:PTPN11 protein, human; C509249:PTPN6 protein, human; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; C516725:Ptpn11 protein, mouse; C509248:Ptpn6 protein, mouse; D054593:SH2 Domain-Containing Protein Tyrosine Phosphatases