The Protein-tyrosine Phosphatase SHP-2 Associates with Tyrosine-phosphorylated Adhesion Molecule PECAM-1 (CD31)*
- From the Receptors and Signal Transduction Section, OIIB, NIDR, National Institutes of Health, Bethesda, Maryland 20892
Abstract
Aggregation of many cell-surface receptors results in tyrosine phosphorylation of numerous proteins. We previously observed the tyrosine phosphorylation of the platelet/endothelial cell adhesion molecule, PECAM-1 (CD31), after FcεRI stimulation in rat basophilic leukemia RBL-2H3 cells. Here we found that PECAM-1 was also transiently tyrosine-phosphoryated after adherence of these cells to fibronectin. Similarly aggregation of the T cell receptor on Jurkat cells also induced this tyrosine phosphorylation. The protein-tyrosine phosphatase SHP-2 is a widely expressed cytosolic enzyme with two Src homology 2 (SH2) domains. SHP-2, but not the related protein-tyrosine phosphatase SHP-1, associated with PECAM-1. This association of the two proteins correlated with the extent of the tyrosine phosphorylation of PECAM-1. A fusion protein containing the two SH2 domains of SHP-2 precipitated PECAM-1 from cell lysates and also directly bound to phosphorylated PECAM-1. In immune precipitate phosphatase assays, there was tyrosine dephosphorylation of PECAM-1. Therefore, integrin and immune receptor activation results in tyrosine phosphorylation of PECAM-1 and the binding of the protein-tyrosine phosphatase SHP-2, which could regulate receptor-mediated signaling in cells.
Footnotes
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↵* The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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↵‡ To whom correspondence should be addressed: Bldg. 10, Rm 1N106, NIDR, National Institutes of Health, Bethesda, MD 20892. Tel.: 301-496-5105; Fax: 301-480-8328; E-mail: rs53x{at}nih.gov.
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↵1 The abbreviations used are: FcεRI, the receptor with high affinity for IgE; GST, glutathioneS-transferase; PAGE, polyacrylamide gel electrophoresis; PECAM-1, platelet/endothelial cell adhesion molecule 1 (also called CD31); RBL-2H3, rat basophilic leukemia 2H3 cell line; SH2, Src homology 2 region; SHP-1, SH2 containing protein-tyrosine phosphatase 1; SHP-2, SH2 containing protein-tyrosine phosphatase 2; MOPS, 3-(N-morpholino)propanesulfonic acid; BSA, bovine serum albumin; ITIM, immunoreceptor tyrosine-based inhibiting motif.
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- Received April 25, 1997.
- Revision received September 2, 1997.
