Conformational dynamics of auto-inhibition in the ER calcium sensor STIM1

Abstract
Data availability
Article and author information

Abstract

The dimeric ER Ca²⁺ sensor STIM1 controls store-operated Ca²⁺ entry (SOCE) through the regulated binding of its CRAC activation domain (CAD) to Orai channels in the plasma membrane. In resting cells, the STIM1 CC1 domain interacts with CAD to suppress SOCE, but the structural basis of this interaction is unclear. Using single-molecule Förster resonance energy transfer (smFRET) and protein crosslinking approaches, we show that CC1 interacts dynamically with CAD in a domain-swapped configuration with an orientation predicted to sequester its Orai-binding region adjacent to the ER membrane. Following ER Ca²⁺ depletion and release from CAD, cysteine crosslinking indicates that the two CC1 domains become closely paired along their entire length in the active Orai-bound state. These findings provide a structural basis for the dual roles of CC1: sequestering CAD to suppress SOCE in resting cells and propelling it towards the plasma membrane to activate Orai and SOCE after store depletion.

Data availability

All data generated or analysed during this study are included in the manuscript and supporting files; Source Data files have been provided for Figure 1 - figure supplement 1-3, Figure 2 - figure supplement 1, Figure 3 - figure supplement 1, Figure 4 - figure supplement 1, Figure 5 - figure supplement 1, Figure 5 - figure supplement 2, Figure 5 - figure supplement 3, Figure 7, Figure 7 - figure supplement 1, and Figure 7 - figure supplement 2.Custom code used to analyze smFRET data is available at https://github.com/vandorp/stim1_paper

Article and author information

Author details

Stijn van Dorp

Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, United States

Competing interests
No competing interests declared.

"This ORCID iD identifies the author of this article:" 0000-0002-9940-7163
Ruoyi Qiu

Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, United States

Competing interests
No competing interests declared.
Ucheor B Choi

Department of Biochemistry, West Virginia University School of Medicine, Morgantown, WV, United States

Competing interests
No competing interests declared.

"This ORCID iD identifies the author of this article:" 0000-0003-1541-2967
Minnie M Wu

Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, United States

Competing interests
No competing interests declared.
Michelle Yen

Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, United States

Competing interests
No competing interests declared.
Michael Kirmiz

Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, United States

Competing interests
No competing interests declared.
Axel T Brunger

Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Howard Hughes Medical Institute, Stanford, United States

Competing interests
Axel T Brunger, Reviewing editor, eLife.

"This ORCID iD identifies the author of this article:" 0000-0001-5121-2036
Richard S Lewis

Immunology Program and Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, United States

For correspondence
rslewis@stanford.edu

Competing interests
Richard S Lewis, Reviewing editor, eLife.

"This ORCID iD identifies the author of this article:" 0000-0002-6010-7403

Funding

National Institutes of Health (R37GM45374)

Richard S Lewis

Mathers Charitable Foundation

Richard S Lewis

Stanford University (Discovery Innovation Award)

Richard S Lewis

National Institutes of Health (R37MH63105)

Axel T Brunger

Dutch Research Council NWO (Rubicon postdoctoral fellowship 825.13.027)

Stijn van Dorp

American Heart Association (postdoctoral fellowship 16POST30780015)

Stijn van Dorp

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Copyright

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.