Association of T cell antigen CD7 with type II phosphatidylinositol-4 kinase, a key component in pathways of inositol phosphate turnover.
CD7 is a 40-kDa glycoprotein that is expressed on prothymocytes and persists during T cell differentiation. CD7 has been demonstrated to generate, like other costimulatory molecules, intracellular signals that modulate T cell function. However, although it binds to phosphatidylinositol 3-kinase (PI 3-kinase), the signaling events mediated by CD7 are not completely understood. In this context, phosphatidylinositol 4-kinase (PI 4-kinase) is a key enzyme involved in a variety of events, from the modeling of the actin cytoskeleton to the activation of protein kinase C. In this study, we show for the first time that PI 4-kinase of 55 kDa can associate with CD7. The enzyme activity was insensitive to wortmannin, but was inhibited by adenosine, a characteristic for type II PI 4-kinase. Together, our findings demonstrate that type II PI 4-kinases are integral components of the CD7 signaling pathway and may play a role of CD7 in co-stimulation and thymic differentiation.
Subrahmanyam
Gosukonda
G
Department of Haematology, Faculty of Medicine, Imperial College of Science, Technology and Medicine, Hammersmith Hospital, London, GB.
Rudd
Christopher E
CE
Schneider
Helga
H
D019870:1-Phosphatidylinositol 4-Kinase / Q000037:antagonists & inhibitors / Q000145:classification / Q000378:metabolism*; D000730:Androstadienes / Q000494:pharmacology; D019011:Antigens, CD7 / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007295:Inositol Phosphates / Q000378:metabolism*; D019169:Jurkat Cells; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011485:Protein Binding; D015398:Signal Transduction; D000077191:Wortmannin
D000730:Androstadienes; D019011:Antigens, CD7; D004791:Enzyme Inhibitors; D007295:Inositol Phosphates; D019869:Phosphatidylinositol 3-Kinases; D019870:1-Phosphatidylinositol 4-Kinase; D000077191:Wortmannin