STIM1-dependent peripheral coupling governs the contractility of vascular smooth muscle cells
- University of Nevada Reno, United States
- University of Nevada, Reno, United States
- Penn State University, United States
- University of Pittsburgh, United States
Abstract
Peripheral coupling between the sarcoplasmic reticulum (SR) and plasma membrane (PM) forms signaling complexes that regulate the membrane potential and contractility of vascular smooth muscle cells (VSMCs). The mechanisms responsible for these membrane interactions are poorly understood. In many cells, STIM1 (stromal-interaction molecule 1), a single transmembrane-domain protein that resides in the endoplasmic reticulum (ER), transiently moves to ER-PM junctions in response to depletion of ER Ca2+ stores and initiates store-operated Ca2+ entry (SOCE). Fully differentiated VSMCs express STIM1 but exhibit only marginal SOCE activity. We hypothesized that STIM1 is constitutively active in contractile VSMCs and maintains peripheral coupling. In support of this concept, we found that the number and size of SR-PM interacting sites were decreased, and SR-dependent Ca2+ signaling processes were disrupted in freshly isolated cerebral artery SMCs from tamoxifen-inducible, SMC-specific STIM1-knockout (Stim1-smKO) mice. VSMCs from Stim1-smKO mice also exhibited a reduction in nanoscale colocalization between Ca2+-release sites on the SR and Ca2+-activated ion channels on the PM, accompanied by diminished channel activity. Stim1-smKO mice were hypotensive, and resistance arteries isolated from them displayed blunted contractility. These data suggest that STIM1 - independent of SR Ca2+ store depletion - is critically important for stable peripheral coupling in contractile VSMCs.
Data availability
All data generated or analyzed during this study are included in the manuscript and supporting files. All source data files and blots images have been provided.
Article and author information
Author details
Michael G Alvarado
Funding
National Heart, Lung, and Blood Institute (R35HL155008)
- Scott Earley
National Heart, Lung, and Blood Institute (R35HL150778)
- Mohamed Trebak
National Heart, Lung, and Blood Institute (K01HL138215)
- Albert L Gonzales
National Heart, Lung, and Blood Institute (R01HL137852)
- Scott Earley
National Heart, Lung, and Blood Institute (R01HL091905)
- Scott Earley
National Heart, Lung, and Blood Institute (R01HL139585)
- Scott Earley
National Heart, Lung, and Blood Institute (R01HL122770)
- Scott Earley
National Heart, Lung, and Blood Institute (R01HL146054)
- Scott Earley
National Institute of Neurological Disorders and Stroke (RF1NS110044)
- Scott Earley
National Institute of Neurological Disorders and Stroke (R61NS115132)
- Scott Earley
National Institute of General Medical Sciences (P20GM130459)
- Scott Earley
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: All animal studies were performed in strict accordance with the guidelines of the Institutional Animal Care and Use Committee (IACUC) of the University of Nevada, Reno, and in accordance with the approved protocol 20-06-2020. All surgery was performed under isoflurane anesthesia, and every effort was made to minimize suffering, including preoperative analgesia provided by subcutaneous injection of 50 µg/kg buprenorphine.
Copyright
© 2022, Krishnan et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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STIM1-dependent peripheral coupling governs the contractility of vascular smooth muscle cells
eLife 11:e70278.
https://doi.org/10.7554/eLife.70278
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