Critical role of novel Thr-219 autophosphorylation for the cellular function of PKCtheta in T lymphocytes

EMBO J. 2005 Nov 16;24(22):3869-80. doi: 10.1038/sj.emboj.7600856. Epub 2005 Oct 27.


Phosphopeptide mapping identified a major autophosphorylation site, phospho (p)Thr-219, between the tandem C1 domains of the regulatory fragment in protein kinase C (PKC)theta. Confirmation of this identification was derived using (p)Thr-219 antisera that reacted with endogenous PKCtheta in primary CD3+ T cells after stimulation with phorbol ester, anti-CD3 or vanadate. The T219A mutation abrogated the capacity of PKCtheta to mediate NF-kappaB, NF-AT and interleukin-2 promoter transactivation, and reduced PKCtheta's ability in Jurkat T cells to phosphorylate endogenous cellular substrates. In particular, the T219A mutation impaired crosstalk of PKCtheta with Akt/PKBalpha in NF-kappaB activation. Yet, this novel (p)Thr-219 site did not affect catalytic activity or second-messenger lipid-binding activity in vitro. Instead, the T219A mutation prevented proper recruitment of PKCtheta in activated T cells. The PKCthetaT219A mutant defects were largely rescued by addition of a myristoylation signal to force its proper membrane localization. We conclude that autophosphorylation of PKCtheta at Thr-219 plays an important role in the correct targeting and cellular function of PKCtheta upon antigen receptor ligation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Membrane / enzymology
  • Enzyme Activation
  • Humans
  • Interleukin-2 / genetics
  • Interleukin-2 / metabolism
  • Isoenzymes / genetics
  • Isoenzymes / metabolism*
  • Jurkat Cells
  • Phosphorylation
  • Promoter Regions, Genetic
  • Protein Kinase C / genetics
  • Protein Kinase C / metabolism*
  • Protein Kinase C-theta
  • Proto-Oncogene Proteins c-akt / metabolism
  • Signal Transduction / physiology
  • T-Lymphocytes / enzymology*
  • Threonine / metabolism*
  • Transcriptional Activation


  • Interleukin-2
  • Isoenzymes
  • Threonine
  • Proto-Oncogene Proteins c-akt
  • PRKCQ protein, human
  • Protein Kinase C
  • Protein Kinase C-theta