Inhibition of the calcium release-activated calcium (CRAC) current in Jurkat T cells by the HIV-1 envelope protein gp160

J Biol Chem. 2002 Feb 22;277(8):6044-50. doi: 10.1074/jbc.M111831200. Epub 2001 Dec 13.

Abstract

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.

MeSH terms

  • Calcium / metabolism*
  • Calcium Signaling / drug effects
  • Calcium Signaling / physiology*
  • HIV Envelope Protein gp160 / pharmacology*
  • HIV-1 / physiology*
  • Humans
  • Isoenzymes / metabolism
  • Jurkat Cells
  • Kinetics
  • Membrane Potentials / drug effects
  • Membrane Potentials / physiology
  • Phytohemagglutinins / pharmacology
  • Protein Kinase C / metabolism
  • Protein Kinase C beta
  • Protein Kinase C-alpha
  • T-Lymphocytes
  • Tetradecanoylphorbol Acetate / pharmacology
  • Thapsigargin / pharmacology

Substances

  • HIV Envelope Protein gp160
  • Isoenzymes
  • Phytohemagglutinins
  • Thapsigargin
  • PRKCA protein, human
  • Protein Kinase C
  • Protein Kinase C beta
  • Protein Kinase C-alpha
  • Tetradecanoylphorbol Acetate
  • Calcium