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.
Metrics
-
- 1,725
- views
-
- 295
- downloads
-
- 25
- citations
Views, downloads and citations are aggregated across all versions of this paper published by eLife.
Download links
A two-part list of links to download the article, or parts of the article, in various formats.
Downloads (link to download the article as PDF)
Open citations (links to open the citations from this article in various online reference manager services)
Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)
STIM1-dependent peripheral coupling governs the contractility of vascular smooth muscle cells
eLife 11:e70278.
https://doi.org/10.7554/eLife.70278
Further reading
-
- Immunology and Inflammation
- Structural Biology and Molecular Biophysics
Increasing evidence suggests that mechanical load on the αβ T-cell receptor (TCR) is crucial for recognizing the antigenic peptide-bound major histocompatibility complex (pMHC) molecule. Our recent all-atom molecular dynamics (MD) simulations revealed that the inter-domain motion of the TCR is responsible for the load-induced catch bond behavior of the TCR-pMHC complex and peptide discrimination (Chang-Gonzalez et al., 2024). To further examine the generality of the mechanism, we perform all-atom MD simulations of the B7 TCR under different conditions for comparison with our previous simulations of the A6 TCR. The two TCRs recognize the same pMHC and have similar interfaces with pMHC in crystal structures. We find that the B7 TCR-pMHC interface stabilizes under ∼15 pN load using a conserved dynamic allostery mechanism that involves the asymmetric motion of the TCR chassis. However, despite forming comparable contacts with pMHC as A6 in the crystal structure, B7 has fewer high-occupancy contacts with pMHC and exhibits higher mechanical compliance during the simulation. These results indicate that the dynamic allostery common to the TCRαβ chassis can amplify slight differences in interfacial contacts into distinctive mechanical responses and nuanced biological outcomes.
-
- Plant Biology
- Structural Biology and Molecular Biophysics
The Calvin-Benson-Bassham cycle (CBBC) performs carbon fixation in photosynthetic organisms. Among the eleven enzymes that participate in the pathway, sedoheptulose-1,7-bisphosphatase (SBPase) is expressed in photo-autotrophs and catalyzes the hydrolysis of sedoheptulose-1,7-bisphosphate (SBP) to sedoheptulose-7-phosphate (S7P). SBPase, along with nine other enzymes in the CBBC, contributes to the regeneration of ribulose-1,5-bisphosphate, the carbon-fixing co-substrate used by ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). The metabolic role of SBPase is restricted to the CBBC, and a recent study revealed that the three-dimensional structure of SBPase from the moss Physcomitrium patens was found to be similar to that of fructose-1,6-bisphosphatase (FBPase), an enzyme involved in both CBBC and neoglucogenesis. In this study we report the first structure of an SBPase from a chlorophyte, the model unicellular green microalga Chlamydomonas reinhardtii. By combining experimental and computational structural analyses, we describe the topology, conformations, and quaternary structure of Chlamydomonas reinhardtii SBPase (CrSBPase). We identify active site residues and locate sites of redox- and phospho-post-translational modifications that contribute to enzymatic functions. Finally, we observe that CrSBPase adopts distinct oligomeric states that may dynamically contribute to the control of its activity.
