Aggregation of the High Affinity IgE Receptor Results in the Tyrosine Phosphorylation of the Surface Adhesion Protein PECAM-1 (CD31)

doi:10.1074/jbc.272.20.13412

Aggregation of the High Affinity IgE Receptor Results in the Tyrosine Phosphorylation of the Surface Adhesion Protein PECAM-1 (CD31)*

From the ^‡Laboratory of Immunology, NIDR, National Institutes of Health and the ^§Facility for Biotechnology Resources, United States Food and Drug Administration, Bethesda, Maryland 20892

Abstract

One of the earliest events after aggregation of the high affinity receptor for IgE (FcεRI) on mast cells is the activation of protein tyrosine kinases resulting in tyrosine phosphorylation of numerous proteins. Using a monoclonal antibody raised against the rat basophilic leukemia RBL-2H3 cells, we identified that platelet/endothelial cell adhesion molecule 1 (PECAM-1 or CD31) was tyrosine phosphorylated in these cells. Aggregation of PECAM-1 did not induce a detectable increase in its tyrosine phosphorylation, nor did it result in degranulation. However, the minimal tyrosine phosphorylation of PECAM-1 in nonstimulated cells was dramatically increased after FcεRI aggregation. This receptor-induced tyrosine phosphorylation of PECAM-1 was an early event, independent of Ca²⁺ influx or of the activation of protein kinase C and of cell adhesion. PECAM-1 is an adhesion molecule that is required for the transmigration of leukocytes across the endothelium into sites of inflammation. Therefore tyrosine phosphorylation of PECAM-1 may modulate its interaction with other molecules, thereby regulating the migration of basophils into inflammatory sites.

Footnotes

↵* 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.
↵¶ To whom correspondence should be addressed: Laboratory of Immunology, Bldg. 10, Rm. 1N106, NIDR, NIH, Bethesda, MD 20892. Tel.: 301-496-5105; Fax: 301×480×8328; E-mail: RS53x{at}nih.gov.
↵1 The abbreviations used are: PECAM-1, platelet/endothelial cell adhesion molecule 1 (also called CD31); PAGE, polyacrylamide gel electrophoresis; Pipes, 1,4-piperazinediethanesulfonic acid; mAb, monoclonal antibody; PBS, phosphate-buffered saline.
- Received October 23, 1996.
- Revision received March 11, 1997.