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Updated: Jan 21, 2026
08:41
Monitoring Endoplasmic Reticulum Calcium Homeostasis Using a Gaussia Luciferase SERCaMP
Published on: September 6, 2015
13.8K
Septins organize endoplasmic reticulum-plasma membrane junctions for STIM1-ORAI1 calcium signalling.
Zachary B Katz1,2, Chen Zhang1, Ariel Quintana1,3
1Division of Signalling and Gene Expression, La Jolla Institute for Immunology, La Jolla, CA, 92037, USA.
Scientific Reports
|July 27, 2019
Summary
Septins indirectly facilitate calcium (Ca2+) signaling by regulating the number of endoplasmic reticulum-plasma membrane junctions and enhancing STIM1-ORAI1 interactions. This coordination links cellular architecture to calcium influx.
Area of Science:
- Cell Biology
- Molecular Biology
- Biophysics
Background:
- Store-dependent calcium entry is mediated by ORAI1 channels at ER-PM junctions, regulated by STIM1.
- Septins, cytoskeletal proteins, are known to modulate STIM1-ORAI1 signaling, but their precise role remains unclear.
Purpose of the Study:
- To investigate the mechanism by which septins influence STIM1-ORAI1 calcium signaling at ER-PM junctions.
- To determine how septins coordinate local calcium signaling with cellular architecture.
Main Methods:
- Super-resolution imaging of ORAI1, STIM1, and septin 4 in living cells.
- Analysis of protein colocalization and localization at ER-PM junctions.
Main Results:
- Septin 4 does not directly colocalize with ORAI1 or confine it to junctions.
- Septins regulate the number of ER-PM junctions and enhance STIM1-ORAI1 interactions within these junctions.
- ORAI1 recruitment to junctions is mediated solely by STIM proteins.
Conclusions:
- Septins facilitate calcium signaling indirectly by modulating ER-PM junction dynamics and STIM1-ORAI1 interactions.
- Septins act as a link between calcium signaling and cellular architecture rearrangements through intermediaries.
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