Novel protein kinase C θ: coronin 1A complex in T lymphocytes

Cell Commun Signal. 2015 Mar 31;13:22. doi: 10.1186/s12964-015-0100-3.

Abstract

Background: Protein kinase C-θ (PKCθ) plays an important role in signal transduction down-stream of the T cell receptor and T cells deficient of PKCθ show impaired NF-κB as well as NFAT/AP-1 activation resulting in strongly decreased IL-2 expression and proliferation. However, it is not yet entirely clear, how the function of PKCθ - upon T cell activation - is regulated on a molecular level.

Findings: Employing a yeast two-hybrid screen and co-immunoprecipitation analyses, we here identify coronin 1A (Coro1A) as a novel PKCθ-interacting protein. We show that the NH2-terminal WD40 domains of Coro1A and the C2-like domain of PKCθ are sufficient for the interaction. Furthermore, we confirm a physical interaction by GST-Coro1A mediated pull-down of endogenous PKCθ protein. Functionally, wild-type but not Coro1A lacking its actin-binding domain negatively interferes with PKCθ-dependent NF-κB, Cyclin D1 and IL-2 transactivation when analysed with luciferase promoter activation assays in Jurkat T cells. This could be phenocopied by pharmacological inhibitors of actin polymerization and PKC, respectively. Mechanistically, Coro1A overexpression attenuates both lipid raft and plasma membrane recruitment of PKCθ in CD3/CD28-activated T cells. Using primary CD3(+) T cells, we observed that (opposite to PKCθ) Coro1A does not localize preferentially to the immunological synapse. In addition, we show that CD3(+) T cells isolated from Coro1A-deficient mice show impaired IKK/NF-κB transactivation.

Conclusions: Together, these findings both in Jurkat T cells as well as in primary T cells indicate a regulatory role of Coro1A on PKCθ recruitment and function downstream of the TCR leading to NF-κB transactivation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Humans
  • Isoenzymes / genetics
  • Isoenzymes / metabolism*
  • Jurkat Cells
  • Mice
  • Microfilament Proteins / genetics
  • Microfilament Proteins / metabolism*
  • Multiprotein Complexes / genetics
  • Multiprotein Complexes / metabolism*
  • NF-kappa B / genetics
  • NF-kappa B / metabolism
  • Protein Kinase C / genetics
  • Protein Kinase C / metabolism*
  • Protein Kinase C-theta
  • Protein Transport / physiology
  • Receptors, Antigen, T-Cell / genetics
  • Receptors, Antigen, T-Cell / metabolism
  • T-Lymphocytes / cytology
  • T-Lymphocytes / metabolism*
  • Transcriptional Activation / physiology

Substances

  • Isoenzymes
  • Microfilament Proteins
  • Multiprotein Complexes
  • NF-kappa B
  • Receptors, Antigen, T-Cell
  • coronin proteins
  • PRKCQ protein, human
  • Prkcq protein, mouse
  • Protein Kinase C
  • Protein Kinase C-theta