Phosphorylation of T cell membrane proteins by activators of protein kinase C

• Published in: The Journal of immunology (1950) Vol. 140; no. 12; pp. 4308 - 4314
• Main Authors: Chatila, TA, Geha, RS
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Am Assoc Immnol 15.06.1988; American Association of Immunologists
• Subjects: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Adult; Antigens, Differentiation, T-Lymphocyte - isolation & purification; Antigens, Differentiation, T-Lymphocyte - metabolism; Biological and medical sciences; Concanavalin A - pharmacology; Dose-Response Relationship, Drug; Enzyme Activation; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Humans; Immunobiology; Immunological reactions in vitro; Isoquinolines - pharmacology; Kinetics; Lymphoblastic transformation (stimulation by antigen, mitogen, mixed lymphocyte reactions); Membrane Proteins - isolation & purification; Membrane Proteins - metabolism; Phosphorylation; Piperazines - pharmacology; Protein Kinase C - antagonists & inhibitors; Protein Kinase C - metabolism; T-Lymphocytes - drug effects; T-Lymphocytes - enzymology; T-Lymphocytes - metabolism; Tetradecanoylphorbol Acetate - pharmacology; Human; Signal transduction; Phosphorylation; Protein kinase C; Membrane protein; Regulation(control); T-Lymphocyte; Activation; In vitro
• ISSN: 0022-1767; 1550-6606
• DOI: 10.4049/jimmunol.140.12.4308

Activation of the enzyme protein kinase C (PKC) plays an important role in T cell activation. We investigated the phosphorylation of CD2, CD3, CD4, CD5, CD7, CD8, CD28 (Tp44), CD43 (sialophorin, gp115), and LFA-1 after incubation of human PBMC with the (PKC) activator PMA. These proteins were chosen for their role in transmembrane signal transduction (CD2, CD3, CD5, CD28, CD43), cell-cell interaction and adhesion (CD2, CD4, CD8, and LFA-1), or involvement in immunodeficiency states (CD43, CD7). CD5, CD7, CD43, and the alpha-chain of LFA-1 were found to be constitutively phosphorylated. PMA induced rapid hyperphosphorylation of CD5, CD7, and CD43, but not of the LFA-1 alpha-chain, and induced the phosphorylation of CD3, CD4, CD8 and of the LFA-1 beta-chain. PMA did not cause the phosphorylation of CD2 and CD28. PMA-induced phosphorylation was partially inhibited by the PKC inhibitor 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine dihydrochloride. Finally, the T cell activator Con A, which binds to the CD3/TCR complex was shown to induce a profile of protein phosphorylation similar to that observed with PMA. We conclude that PKC-mediated phosphorylation of T cell Ag may represent an important regulatory mechanism that governs the process of T cell activation.