Divergent regulation of phospholipase C-alpha and phospholipase C-gamma transcripts during activation of a human T cell line.
Ligand-induced activation of T cells results in stimulation of phosphatidylinositol-specific phospholipase C (PI-PLC). A structurally diverse family of PI-PLC isoforms has recently been defined, and more than one isoform is frequently coexpressed in a single cell or tissue, suggesting that different forms may play distinct roles in cellular activation, proliferation, or differentiation. We show here that both PLC-alpha and PLC-gamma are expressed in rat splenic T cells and in Jurkat cells (a human T cell line). Activation of Jurkat cells with the combination of PMA and PHA leads to increased expression of PLC-alpha message and decreased expression of PLC-gamma message after 4 h of stimulation. The increase in PLC-alpha transcripts was detectable at 4 h, maximal at 6 h, and remained elevated for at least 24 h. The decrease in PLC-gamma message was transient, with a maximal effect at 4 h, and a return to basal levels by 6 h. Changes in PI-PLC transcripts were also induced by the combination of PMA and the calcium ionophore, ionomycin. These data demonstrate that the expression of transcripts for PLC-alpha and PLC-gamma can be differentially regulated during a cellular response, and raise the possibility that these two isoforms of PI-PLC subserve distinct functions in T cell activation.
Goldfien
R D
RD
Department of Medicine, Veterans Administration Medical Center, San Francisco, CA 94121.
Seaman
W E
WE
Hempel
W M
WM
Imboden
J B
JB
D002460:Cell Line; D006801:Humans; D007527:Isoenzymes / Q000096:biosynthesis*; D008213:Lymphocyte Activation; D010835:Phytohemagglutinins / Q000494:pharmacology; D013601:T-Lymphocytes / Q000276:immunology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014158:Transcription, Genetic; D010738:Type C Phospholipases / Q000096:biosynthesis* / Q000235:genetics
D007527:Isoenzymes; D010835:Phytohemagglutinins; D010738:Type C Phospholipases; D013755:Tetradecanoylphorbol Acetate