Synergistic action of protein kinase C theta and calcineurin is sufficient for Fas ligand expression and induction of a crmA-sensitive apoptosis pathway in Jurkat T cells

Eur J Immunol. 1999 Nov;29(11):3549-61. doi: 10.1002/(SICI)1521-4141(199911)29:11<3549::AID-IMMU3549>3.0.CO;2-Q.

Abstract

Deletion of activated peripheral T cell clones by apoptosis requires the regulated expression of Fas ligand (FasL) and sensitization of these cells to CD95-mediated signaling. To investigate the signaling pathways responsible for FasL expression in T cells, we tested-besides subfamily-selective protein kinase C (PKC) inhibitors - the effect of constitutively active mutants of representatives of all PKC subfamilies, i.e. PKCalpha,epsilon,theta,iota, on FasL luciferase promoter reporter constructs. In synergy with a constitutively active form of protein phosphatase 2B calcineurin (CaN), only PKCtheta, but not PKCalpha,epsilon,iota, preferentially induced FasL promoter reporter activity and, consequently, FasL protein expression in Jurkat T cells. Activation of an inducible PKCtheta AE-estrogen receptor fusion mutant led to a CaN-dependent and rapid FasL reporter activity detected as early as 4 h after addition of 4-hydroxytamoxifen, incidating a direct effect of PKCtheta action on FasL expression. Consistently, in Jurkat T cells, expression of PKCtheta AE / CaN significantly enhanced FasL protein expression and apoptosis in a CD95-dependent manner since cell death was not observed in T cells co-expressing the caspase-8 inhibitor crmA. Taken together, our results support the notion that PKCtheta and CaN are sufficient to regulate apoptosis through FasL expression.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antigens, Polyomavirus Transforming / genetics
  • Apoptosis*
  • Calcineurin / genetics
  • Calcineurin / metabolism*
  • Fas Ligand Protein
  • Gene Expression
  • Humans
  • Ionomycin / pharmacology
  • Isoenzymes / genetics
  • Isoenzymes / metabolism*
  • Jurkat Cells
  • Ligands
  • MAP Kinase Kinase Kinase 1*
  • MAP Kinase Kinase Kinases / metabolism
  • MAP Kinase Signaling System
  • Membrane Glycoproteins / biosynthesis
  • Membrane Glycoproteins / genetics*
  • Mitogens / pharmacology
  • NF-kappa B / metabolism
  • Promoter Regions, Genetic*
  • Protein Kinase C / genetics
  • Protein Kinase C / metabolism*
  • Protein Kinase C-theta
  • Protein-Serine-Threonine Kinases*
  • Serpins / metabolism*
  • Signal Transduction
  • Tetradecanoylphorbol Acetate / pharmacology
  • Transcription Factor AP-1 / metabolism
  • Transcription, Genetic
  • Transcriptional Activation
  • Viral Proteins*

Substances

  • Antigens, Polyomavirus Transforming
  • FASLG protein, human
  • Fas Ligand Protein
  • Isoenzymes
  • Ligands
  • Membrane Glycoproteins
  • Mitogens
  • NF-kappa B
  • Serpins
  • Transcription Factor AP-1
  • Viral Proteins
  • Ionomycin
  • interleukin-1beta-converting enzyme inhibitor
  • Protein-Serine-Threonine Kinases
  • PRKCQ protein, human
  • Protein Kinase C
  • Protein Kinase C-theta
  • MAP Kinase Kinase Kinase 1
  • MAP Kinase Kinase Kinases
  • MAP3K1 protein, human
  • Calcineurin
  • Tetradecanoylphorbol Acetate