Lysophosphatidylcholine is a regulator of tyrosine kinase activity and intracellular Ca super(2+) level in Jurkat T cell line

• Published in: Immunology letters Vol. 91; no. 1; pp. 17 - 21
• Main Authors: Legradi, A, Chitu, V, Szukacsov, V, Fajka-Boja, R, Szekely Szucs, K, Monostori, E
• Format: Journal Article
• Language: English
• Published: 30-01-2004
• ISSN: 0165-2478
• DOI: 10.1016/j.imlet.2003.10.009

Lysophospholipids, particularly lysophosphatidylcholine (lyso-PC), have been implicated in modulating T cell functions at the sites of inflammation and atherosclerosis. Although the chemotactic and immunomodulatory effects are well documented, the exact signaling pathway of lyso-PC action is poorly defined. In this work, we studied the earliest biochemical events in T cells triggered by lyso-PC. A marked and immediate tyrosine phosphorylation was induced in the leukemic T cell line, Jurkat. Phosphorylation of cellular substrates included src family kinase, p56 super(lck) and syk family kinase, ZAP70. The lyso-PC induced tyrosine phosphorylation was largely dependent on the presence of functional p56 super(lck). Tyrosine phosphorylation was followed by the elevation of intracellular Ca super(2+) concentration. The magnitude of the mobilization of the intracellular Ca super(2+) was similar in the absence of the p56 super(lck) activity in JCaM1.6 cells as in Jurkat cells, however, it was slightly but reproducibly delayed compared to that in the wild type cells. Inhibition of the Ser/Thr kinases and tyrosine kinases with staurosporine and genistein, respectively, decreased the rise in the intracellular Ca super(2+) content. Moreover, pertussis toxin completely blocked the Ca super(2+) signal supporting the role of the G-protein coupled LPC receptor in this event.