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STIM1 gates the store-operated calcium channel ORAI1 in vitro

Yubin Zhou1, Paul Meraner, Hyoung T Kwon

  • 1Immune Disease Institute and Program in Cellular and Molecular Medicine, Children's Hospital, Boston, Massachusetts, USA.

Nature Structural & Molecular Biology
|December 29, 2009
PubMed

Insights

Researchers studied store-operated calcium (Ca2+) entry by examining the interaction between stromal interaction molecule 1 (STIM1) and ORAI1 channels. They found STIM1 can gate ORAI1 channels in vitro, paving the way for further research.

Area of Science:

  • Cellular Biology
  • Immunology
  • Biochemistry

Background:

  • Store-operated Ca2+ entry is crucial for T cell and mast cell function.
  • This process relies on stromal interaction molecule 1 (STIM1) and ORAI1 channel proteins.

Purpose of the Study:

  • To investigate the in vitro interaction between STIM1 and ORAI1.
  • To determine if STIM1 alone is sufficient to gate ORAI1 channels.

Main Methods:

  • Expressed human ORAI1 in yeast (Saccharomyces cerevisiae).
  • Isolated sealed membrane vesicles containing ORAI1.
  • Performed in vitro Ca2+ flux assays using recombinant STIM1.

Main Results:

  • Recombinant STIM1 successfully opened wild-type ORAI1 channels.
  • STIM1 did not open ORAI1 channels with pore mutations (E106Q) or SCID mutations (R91W).
  • The STIM1-ORAI1 interaction is sufficient for ORAI1 channel gating.

Conclusions:

  • The STIM1-ORAI1 interaction is sufficient to gate ORAI1 channels independently of other cellular proteins.
  • This study provides a foundation for detailed biochemical and biophysical analysis of ORAI1 channel gating mechanisms.

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