Single Channel Properties and Regulated Expression of Ca2+ Release-Activated Ca2+ (Crac) Channels in Human T Cells
| Autor: | Alla F. Fomina, Christopher M. Fanger, Michael D. Cahalan, J. Ashot Kozak |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
Patch-Clamp Techniques
Thapsigargin T-Lymphocytes Biology Lymphocyte Activation Jurkat cells Membrane Potentials Jurkat Cells 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Cyclosporin a T lymphocyte Humans Calcium Signaling Patch clamp Phytohemagglutinins Egtazic Acid Ca2+ signaling Chelating Agents 030304 developmental biology Calcium signaling Membrane potential 0303 health sciences Ca2+ channel Voltage-dependent calcium channel T cell activation Sodium Cell Biology CRAC channel Up-Regulation Kinetics Biochemistry chemistry Biophysics Calcium Original Article Calcium Channels Ion Channel Gating 030217 neurology & neurosurgery Intracellular |
| Zdroj: | The Journal of Cell Biology Fomina, AF; Fanger, CM; Kozak, JA; & Cahalan, MD. (2000). Single channel properties and regulated expression of Ca2+ release-activated Ca2+ (CRAC) channels in human T cells. Journal of Cell Biology, 150(6), 1435-1444. doi: 10.1083/jcb.150.6.1435. UC Irvine: Retrieved from: http://www.escholarship.org/uc/item/9x79w908 |
| ISSN: | 1540-8140 0021-9525 |
| DOI: | 10.1083/jcb.150.6.1435 |
| Popis: | Although the crucial role of Ca(2+) influx in lymphocyte activation has been well documented, little is known about the properties or expression levels of Ca(2+) channels in normal human T lymphocytes. The use of Na(+) as the permeant ion in divalent-free solution permitted Ca(2+) release-activated Ca(2+) (CRAC) channel activation, kinetic properties, and functional expression levels to be investigated with single channel resolution in resting and phytohemagglutinin (PHA)-activated human T cells. Passive Ca(2+) store depletion resulted in the opening of 41-pS CRAC channels characterized by high open probabilities, voltage-dependent block by extracellular Ca(2+) in the micromolar range, selective Ca(2+) permeation in the millimolar range, and inactivation that depended upon intracellular Mg(2+) ions. The number of CRAC channels per cell increased greatly from approximately 15 in resting T cells to approximately 140 in activated T cells. Treatment with the phorbol ester PMA also increased CRAC channel expression to approximately 60 channels per cell, whereas the immunosuppressive drug cyclosporin A (1 microM) suppressed the PHA-induced increase in functional channel expression. Capacitative Ca(2+) influx induced by thapsigargin was also significantly enhanced in activated T cells. We conclude that a surprisingly low number of CRAC channels are sufficient to mediate Ca(2+) influx in human resting T cells, and that the expression of CRAC channels increases approximately 10-fold during activation, resulting in enhanced Ca(2+) signaling. |
| Databáze: | OpenAIRE |
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