Inhibition of the calcium release-activated calcium (CRAC) current in Jurkat T cells by the HIV-1 envelope protein gp160.
The HIV-1 envelope glycoprotein gp120/160 has pleiotropic effects on T cell function. We investigated whether Ca(2+) signaling, a crucial step for T cell activation, was altered by prolonged exposure of Jurkat T cells to gp160. Microfluorometric measurements showed that Jurkat cells incubated with gp160 had smaller (approximately 40%) increases in [Ca(2+)](i) in response to phytohemagglutinin and had a reduced Ca(2+) influx (approximately 25%). gp160 had similar effects on Jurkat cells challenged with thapsigargin. We used the patch clamp technique to record the Ca(2+) current, which is responsible for Ca(2+) influx and has properties of the calcium release-activated Ca(2+) current (I(CRAC)). gp160 reduced I(CRAC) by approximately 40%. The inhibitory effects of gp160 were antagonized by staurosporine (0.1 microm), an inhibitor of protein-tyrosine kinases and protein kinase Cs (PKCs), and by Gö 6976 (5 microm), an inhibitor acting especially on PKC alpha and PKC beta I. 12-O-Tetradecanoyl phorbol 13-acetate (16 nm), a PKC activator, reproduced the effects of gp160 in untreated cells. A Western blotting analysis of PKC isoforms alpha, beta I, delta, and zeta showed that only the cellular distribution of PKC alpha and -beta I were significantly modified by gp160. In addition, gp160 was able to modify the subcellular distribution of PKC alpha and PKC beta I caused by phytohemagglutinin. Therefore the reduction in I(CRAC) caused by prolonged incubation with gp160 is probably mediated by PKC alpha or -beta I.
Dellis
Olivier
O
Electrophysiologie des Membranes, Université Denis Diderot (Paris7), 2 place Jussieu, 75251 Paris cedex 05, France. odellis@moka.ccr.jussieu.fr
Gangloff
Sophie C
SC
Paulais
Marc
M
Tondelier
Danielle
D
Rona
Jean-Pierre
JP
Brouillard
Franck
F
Bouteau
François
F
Guenounou
Moncef
M
Teulon
Jacques
J
D002118:Calcium / Q000378:metabolism*; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D019302:HIV Envelope Protein gp160 / Q000494:pharmacology*; D015497:HIV-1 / Q000502:physiology*; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism; D019169:Jurkat Cells; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D010835:Phytohemagglutinins / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism; D064546:Protein Kinase C beta; D051571:Protein Kinase C-alpha; D013601:T-Lymphocytes; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D019284:Thapsigargin / Q000494:pharmacology
D019302:HIV Envelope Protein gp160; D007527:Isoenzymes; D010835:Phytohemagglutinins; D019284:Thapsigargin; C496628:PRKCA protein, human; D011493:Protein Kinase C; D064546:Protein Kinase C beta; D051571:Protein Kinase C-alpha; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium