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Updated: Jul 18, 2026

Whole-Cell Recording of Calcium Release-Activated Calcium (CRAC) Currents in Human T Lymphocytes
15:29

Whole-Cell Recording of Calcium Release-Activated Calcium (CRAC) Currents in Human T Lymphocytes

Published on: December 21, 2010

The Ca(2+)-activated K(+) channel KCa3.1 compartmentalizes in the immunological synapse of human T lymphocytes

Stella A Nicolaou1, Lisa Neumeier, Youqing Peng

  • 1Department of Internal Medicine, 231 Albert Sabin Way, University of Cincinnati, Cincinnati, OH 45267-0585, USA.

American Journal of Physiology. Cell Physiology
|December 8, 2006
PubMed

Insights

KCa3.1 channels are recruited to the immunological synapse (IS) in human T cells upon activation, contributing to T cell signaling. This redistribution occurs independently of their calcium (Ca2+) influx blocking function.

Area of Science:

  • Immunology
  • Cell Biology
  • Ion Channel Physiology

Background:

  • T cell receptor engagement triggers the formation of the immunological synapse (IS), crucial for T cell activation and calcium influx.
  • KCa3.1 channels are known to regulate calcium signaling and membrane potential in activated T cells.
  • The membrane distribution of KCa3.1 channels during T cell activation remains uncharacterized.

Purpose of the Study:

  • To investigate the translocation of KCa3.1 channels to the immunological synapse (IS) in human T cells during T cell activation.
  • To characterize the functional and localization properties of YFP-tagged KCa3.1 channels.

Main Methods:

  • Utilized YFP-tagged KCa3.1 channels in human T cells to track channel distribution.
  • Induced IS formation using anti-CD3/CD28 antibody-coated beads and Epstein-Barr virus-infected B cells.
  • Employed confocal and fluorescence microscopy, alongside immunolabeling for F-actin and CD3epsilon, to visualize KCa3.1 localization.
  • Assessed the effect of the KCa3.1 blocker TRAM-34 on channel translocation and calcium influx.

Main Results:

  • YFP-tagged KCa3.1 channels exhibited wild-type electrophysiological and pharmacological properties.
  • Upon T cell activation, KCa3.1 channels were found to colocalize with F-actin and CD3epsilon at the IS.
  • KCa3.1 channels redistributed to the IS shortly after antigen presentation and remained there for at least 15-30 minutes.
  • Blocking KCa3.1 channels with TRAM-34 inhibited calcium influx but did not prevent channel translocation to the IS.

Conclusions:

  • KCa3.1 channels dynamically translocate to the immunological synapse in human T cells following activation.
  • The redistribution of KCa3.1 channels to the IS is an early event in T cell activation, preceding or independent of their role in calcium influx.
  • These findings identify KCa3.1 channels as components of the T cell signaling complex at the IS.

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