Mechanism of diacylglycerol-induced membrane targeting and activation of protein kinase C

Heather R. Melowic, Robert V. Stahelin, Nichole R. Blatner, Wen Tian, Keitaro Hayashi, Amnon Altman, Wonhwa Cho

Research output: Contribution to journalArticle

55 Scopus citations

Abstract

Protein kinase C (PKC) θis a novel PKC that plays a key role in T lymphocyte activation. PKCθ has been shown to be specifically recruited to the immunological synapse in response to T cell receptor activation. To understand the basis of its unique subcellular localization properties, we investigated the mechanism of in vitro and cellular sn-1,2-diacylglycerol (DAG)-mediated membrane binding of PKCθ. PKCθ showed phosphatidylserine selectivity in membrane binding and kinase action, which contributes to its translocation to the phosphatidylserine-rich plasma membrane in HEK293 cells. Unlike any other PKCs characterized so far, the isolated C1B domain of PKCθ had much higher affinity for DAG-containing membranes than the C1A domain. Also, the mutational analysis indicates that the C1B domain plays a predominant role in the DAG-induced membrane binding and activation of PKCθ. Furthermore, the Ca2+-independent C2 domain of PKCθ has significant affinity for anionic membranes, and the truncation of the C2 domain greatly enhanced the membrane affinity and enzyme activity of PKCθ. In addition, membrane binding properties of Y90E and Y90F mutants indicate that phosphorylation of Tyr90 of the C2 domain enhances the affinity of PKCθfor model and cell membranes. Collectively, these results show that PKCθ has a unique membrane binding and activation mechanism that may account for its subcellular targeting properties.

Original languageEnglish (US)
Pages (from-to)21467-21476
Number of pages10
JournalJournal of Biological Chemistry
Volume282
Issue number29
DOIs
StatePublished - Jul 20 2007

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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