Cancer Institute A national cancer institute
designated cancer center

James L. Zehnder, M.D.

Publication Details

  • THE CELL-ADHESION MOLECULE CD31 IS PHOSPHORYLATED AFTER CELL ACTIVATION - DOWN-REGULATION OF CD31 IN ACTIVATED LYMPHOCYTES-T JOURNAL OF BIOLOGICAL CHEMISTRY Zehnder, J. L., Hirai, K., Shatsky, M., McGregor, J. L., Levitt, L. J., Leung, L. L. 1992; 267 (8): 5243-5249

    Abstract:

    We report the independent cloning of the cDNA for CD31, a recently described cell adhesion molecule of the immunoglobulin gene superfamily present on platelets, granulocytes, monocytes, lymphocytes, and endothelial cells. Northern analysis revealed three major mRNA transcripts in Jurkat (a human T cell line) and K562 and HEL (leukemia cell lines) cells with an additional 5.3-kilobase transcript seen in cultured human umbilical vein endothelial cells. Following T cell activation, CD31 mRNA was down-regulated by Northern analysis, and decreased CD31 protein expression was confirmed by immunoblots. The down-regulation of CD31 was partially mediated by decreased transcription as demonstrated by nuclear run-on studies. CD31 became rapidly phosphorylated in platelets, Jurkat cells, and endothelial cells after cell activation. We were unable to demonstrate the presence of a phosphotyrosine in CD31 using monoclonal and polyclonal phosphotyrosine antibodies. In addition, CD31 phosphorylation in platelets was induced by phorbol ester and was blocked by staurosporin, a protein kinase C inhibitor, suggesting that CD31 phosphorylation is mediated by protein kinase C and involves serine and/or threonine residues. The phosphorylation of CD31 following cell activation may modulate its cellular adhesiveness, and the down-regulation of its expression may serve to impart target specificity and to localize effector lymphocytes to areas of inflammation.

    View details for Web of Science ID A1992HH74700040

    View details for PubMedID 1544907

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