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Real-time Live Imaging of T-cell Signaling Complex Formation
10:31

Real-time Live Imaging of T-cell Signaling Complex Formation

Published on: June 23, 2013

Protein kinase C theta cooperates with Vav1 to induce JNK activity in T-cells

A Möller1, O Dienz, S P Hehner

  • 1German Cancer Research Center, Division of Immunochemistry (G0200), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.

The Journal of Biological Chemistry
|March 29, 2001
PubMed

Insights

Vav1 and protein kinase C theta (PKCtheta) synergize to activate c-Jun N-terminal kinase (JNK) in T-cells. Vav1 acts upstream of PKCtheta, influencing JNK activation through both calcium-dependent and independent pathways.

Area of Science:

  • Immunology
  • Cell Signaling
  • Molecular Biology

Background:

  • T-cell activation involves complex signaling pathways crucial for immune responses.
  • Protein kinase C theta (PKCtheta) and Vav1 are key regulators in T-cell signaling.
  • Understanding their interplay is vital for deciphering T-cell leukemia pathogenesis.

Purpose of the Study:

  • To investigate the synergistic roles of Vav1 and PKCtheta in T-cell activation.
  • To elucidate the signaling pathways involved in JNK and p38 MAP kinase activation.
  • To determine the upstream/downstream relationship between Vav1 and PKCtheta in T-cell signaling.

Main Methods:

  • Transfection of dominant-negative constructs for Vav1 and PKCtheta.
  • Reporter gene assays assessing AP-1 and CD28RE/AP element activity.
  • Gel filtration chromatography to analyze protein complex formation.
  • Stimulation of T-cells with anti-CD3/anti-CD28 antibodies.

Main Results:

  • Vav1 and PKCtheta synergistically activate c-Jun N-terminal kinase (JNK), but not p38 MAP kinase.
  • Co-stimulation of T-cells induces transcription via AP-1 and IL-2 promoter elements, dependent on Vav1 and PKCtheta.
  • Vav1 functions upstream of PKCtheta in a pathway leading to synergistic JNK activation.
  • Vav1 signals to JNK via both PKCtheta-dependent (Ca2+-independent) and independent (Ca2+-dependent) routes.

Conclusions:

  • Vav1 and PKCtheta form a critical signaling axis for JNK activation in T-cells.
  • The interplay between Vav1 and PKCtheta regulates key transcription factors involved in T-cell activation.
  • Vav1's upstream localization and dual signaling pathways highlight its central role in T-cell leukemia signaling.

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