Phospholipid metabolism and T cell activation: receptor triggering is associated with the inhibition of phosphatidylserine synthesis.
Activation of Jurkat T lymphocytes to produce IL2 is accompanied by a strong inhibition of phosphatidylserine (PS) synthesis. This inhibition was obtained either with the mitogenic lectin PHA, anti-CD3 monoclonal antibodies (mAb), anti-CD2 mAb or anti-Ti mAb. Bypassing membrane receptor signalling, by using a Ca2+ ionophore or a protein phosphatase inhibitor, sodium ortho-vanadate, also results in a marked inhibition of PS synthesis. Activators of phospholipid -Ca2+ dependent protein kinase C (PKC) did not significantly modify PS synthesis, suggesting that the observed changes only involve the transduction of the first activation signal. PS being a necessary cofactor for PKC, our results strongly suggest that the inhibition of PS synthesis induced by receptor triggering exerts a feed back control on PKC therefore leading to a transient activation of the enzyme upon full lymphocyte activation.
Pelassy
C
C
INSERM U210, Faculté de Médecine (Pasteur), Nice, France.
Aussel
C
C
Fehlmann
M
M
D000911:Antibodies, Monoclonal; D015703:Antigens, CD / Q000502:physiology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000502:physiology; D018801:CD2 Antigens; D017252:CD3 Complex; D002460:Cell Line; D006801:Humans; D008213:Lymphocyte Activation / Q000187:drug effects / Q000502:physiology*; D010718:Phosphatidylserines / Q000096:biosynthesis*; D010835:Phytohemagglutinins / Q000494:pharmacology; D011493:Protein Kinase C / Q000502:physiology; D011948:Receptors, Antigen, T-Cell / Q000502:physiology; D011971:Receptors, Immunologic / Q000502:physiology; D012694:Serine / Q000378:metabolism; D013601:T-Lymphocytes / Q000378:metabolism*; D014316:Tritium
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D018801:CD2 Antigens; D017252:CD3 Complex; D010718:Phosphatidylserines; D010835:Phytohemagglutinins; D011948:Receptors, Antigen, T-Cell; D011971:Receptors, Immunologic; D014316:Tritium; D012694:Serine; D011493:Protein Kinase C