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Actin cytoskeleton regulates calcium dynamics and NFAT nuclear duration
Fabiola V Rivas1, James P O'Keefe, Maria-Luisa Alegre
1Department of Pathology, The University of Chicago, Chicago, Illinois 60637, USA.
Molecular and Cellular Biology
|January 30, 2004
Summary
The actin cytoskeleton unexpectedly inhibits T-cell receptor (TCR)-induced cytokine production. Disrupting actin polymerization prolongs calcium signaling and enhances interleukin 2 production, revealing a novel regulatory role in T-cell activation.
Area of Science:
- Immunology
- Cell Biology
- Cytoskeletal Dynamics
Background:
- T-cell activation involves actin polymerization, T-cell receptor (TCR) capping, and immunological synapse formation.
- The precise role of actin-dependent events in T-cell function remains incompletely understood.
Purpose of the Study:
- To investigate the role of the actin cytoskeleton in T-cell receptor (TCR)-induced cytokine production.
- To elucidate the impact of actin dynamics on intracellular calcium signaling and downstream transcription factor activation.
Main Methods:
- Disruption of actin polymerization using pharmacological inhibitors.
- Measurement of intracellular calcium levels following T-cell stimulation.
- Analysis of nuclear factor of activated T cells (NFAT) duration and interleukin 2 promoter activity.
- Assessment of plasma membrane Ca(2+) ATPase expression.
Main Results:
- Disruption of actin polymerization led to prolonged intracellular calcium elevation and sustained NFAT nuclear duration.
- Blockade of actin polymerization resulted in augmented interleukin 2 promoter activity.
- Actin polymerization inhibition affected the surface expression of plasma membrane Ca(2+) ATPase, suggesting a role in calcium export.
Conclusions:
- The actin cytoskeleton plays an unexpected negative regulatory role in TCR-induced cytokine production.
- Actin dynamics modulate the duration of Ca(2+)-NFAT signaling, impacting T-cell activation downstream of receptor clustering.