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Single-Cell Calcium Imaging for Studying the Activation of Calcium Ion Channels
Published on: December 13, 2024
Temperature-dependent STIM1 activation induces Ca²+ influx and modulates gene expression
Bailong Xiao1, Bertrand Coste, Jayanti Mathur
1Dorris Neuroscience Center, Department of Cell Biology, The Scripps Research Institute, La Jolla, California, USA.
Nature Chemical Biology
|April 19, 2011
Summary
Temperature regulates cellular calcium signaling. STIM1 protein clusters and activates calcium influx in response to cooling, independent of calcium stores, revealing temperature as a key regulator of STIM1 function.
Area of Science:
- Cell Biology
- Molecular Biology
- Physiology
Background:
- Intracellular calcium (Ca2+) is vital for cellular processes, including immune cell function.
- Store-operated Ca2+ entry (SOCE) is a primary mechanism for Ca2+ influx, typically triggered by endoplasmic reticulum (ER) Ca2+ depletion.
- STIM1 acts as an ER Ca2+ sensor, initiating SOCE by interacting with Orai1 channels at ER-plasma membrane junctions.
Purpose of the Study:
- To investigate the role of temperature as a regulator of STIM1 and SOCE.
- To determine if temperature changes can activate STIM1 independently of ER Ca2+ store depletion.
- To explore the impact of temperature shifts on STIM1-Orai1 interactions and downstream cellular responses.
Main Methods:
- Cellular heating and cooling experiments.
- Monitoring STIM1 clustering using fluorescence microscopy.
- Measuring Ca2+ influx through Orai1 channels.
- Analyzing STIM1-dependent gene expression in Jurkat T cells.
Main Results:
- STIM1 clustered at ER-plasma membrane junctions at temperatures above 35 °C, independent of ER Ca2+ store depletion.
- Orai1-mediated Ca2+ influx occurred as a heat off-response after cooling.
- High temperatures inhibited the functional coupling between STIM1 and Orai1.
- Physiologically relevant temperature shifts influenced STIM1-dependent gene expression in Jurkat T cells.
Conclusions:
- Temperature is a significant regulator of STIM1 activation and SOCE.
- The heat off-response is likely due to temperature-dependent inhibition of STIM1-Orai1 coupling.
- Temperature shifts can modulate gene expression in immune cells via STIM1 signaling pathways.
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