STIM1 regulates TRPC6 heteromultimerization and subcellular location.
Letizia Albarrán1, Natalia Dionisio1, Esther Lopez1
1*Department of Physiology, Cell Physiology Research Group, University of Extremadura, 10003 Cáceres, Spain.
The Biochemical Journal
|August 5, 2014
Summary
Stromal interaction molecule 1 (STIM1) regulates the plasma membrane expression and endoplasmic reticulum translocation of Transient Receptor Potential Canonical 6 (TRPC6) channels. This STIM1-mediated TRPC6 relocation impacts calcium (Ca2+) signaling pathways.
Area of Science:
- Cellular Biology
- Molecular Physiology
- Calcium Signaling
Background:
- Stromal interaction molecule 1 (STIM1) is a key regulator of store-operated calcium channels, sensing endoplasmic reticulum calcium levels.
- The precise mechanisms by which STIM1 influences the heteromultimerization and cellular localization of Transient Receptor Potential Canonical (TRPC) channels, particularly TRPC6, remain incompletely understood.
- TRPC6 channels are primarily implicated in second messenger-activated calcium influx pathways.
Purpose of the Study:
- To investigate the role of STIM1 in regulating the plasma membrane expression and intracellular trafficking of TRPC6 channels.
- To elucidate the functional consequences of STIM1-mediated TRPC6 relocation on cellular calcium homeostasis and signaling.
Main Methods:
- Investigated STIM1's effect on TRPC6 expression at the plasma membrane and its translocation to the endoplasmic reticulum.
- Assessed the impact of altered TRPC6 plasma membrane expression on its association with TRPC1 and TRPC3.
- Measured passive calcium efflux and basal cytosolic calcium concentration in response to TRPC6 expression in the endoplasmic reticulum.
Main Results:
- STIM1 was found to regulate TRPC6 expression at the plasma membrane and induce its translocation to the endoplasmic reticulum.
- Reduced TRPC6 plasma membrane expression led to decreased association with TRPC1 and TRPC3.
- TRPC6 expression in the endoplasmic reticulum increased passive calcium efflux and basal cytosolic calcium levels, without affecting endoplasmic reticulum calcium accumulation.
Conclusions:
- A novel mechanism is proposed where STIM1 regulates TRPC6 channel localization and function.
- This STIM1-TRPC6 interaction may serve to modulate second messenger-operated calcium entry while simultaneously potentiating store-operated calcium influx.
- Findings provide new insights into the complex interplay between STIM1 and TRPC channels in controlling cellular calcium dynamics.
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