Premium
Critical role of novel Thr‐219 autophosphorylation for the cellular function of PKCθ in T lymphocytes
Author(s) -
Thuille Nikolaus,
Heit Isabelle,
Fresser Friedrich,
Krumböck Nina,
Bauer Birgit,
Leuthaeusser Sabine,
Dammeier Sascha,
Graham Caroline,
Copeland Terry D,
Shaw Steve,
Baier Gottfried
Publication year - 2005
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/sj.emboj.7600856
Subject(s) - biology , autophosphorylation , protein kinase c , microbiology and biotechnology , function (biology) , phosphorylation , protein kinase a
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)θ. Confirmation of this identification was derived using (p)Thr‐219 antisera that reacted with endogenous PKCθ in primary CD3 + T cells after stimulation with phorbol ester, anti‐CD3 or vanadate. The T219A mutation abrogated the capacity of PKCθ to mediate NF‐κB, NF‐AT and interleukin‐2 promoter transactivation, and reduced PKCθ's ability in Jurkat T cells to phosphorylate endogenous cellular substrates. In particular, the T219A mutation impaired crosstalk of PKCθ with Akt/PKBα in NF‐κB 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 PKCθ in activated T cells. The PKCθT219A mutant defects were largely rescued by addition of a myristoylation signal to force its proper membrane localization. We conclude that autophosphorylation of PKCθ at Thr‐219 plays an important role in the correct targeting and cellular function of PKCθ upon antigen receptor ligation.