Lysophosphatidylcholine is a regulator of tyrosine kinase activity and intracellular Ca(2+) level in Jurkat T cell line.
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(lck) and syk family kinase, ZAP70. The lyso-PC induced tyrosine phosphorylation was largely dependent on the presence of functional p56(lck). Tyrosine phosphorylation was followed by the elevation of intracellular Ca(2+) concentration. The magnitude of the mobilization of the intracellular Ca(2+) was similar in the absence of the p56(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(2+) content. Moreover, pertussis toxin completely blocked the Ca(2+) signal supporting the role of the G-protein coupled LPC receptor in this event.
Légrádi
Adám
A
Lymphocyte Signal Transduction Laboratory, Institute of Genetics, Biological Research Center of Hungarian Academy of Sciences, PO Box 521, Temesvári krt. 62, H-6726 Szeged, Hungary.
Chitu
Violeta
V
Szukacsov
Valéria
V
Fajka-Boja
Roberta
R
Székely Szücs
Kinga
K
Monostori
Eva
E
D002118:Calcium / Q000378:metabolism*; D006801:Humans; D019169:Jurkat Cells; D008244:Lysophosphatidylcholines / Q000378:metabolism*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D013601:T-Lymphocytes / Q000201:enzymology*
D008244:Lysophosphatidylcholines; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D002118:Calcium