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Structural Insights into Ca2+ Permeation through Orai Channels.
Yang Li1, Xue Yang1, Yuequan Shen1
1State Key Laboratory of Medicinal Chemical Biology and College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin 300071, China.
Cells
|November 27, 2021
Summary
Orai channels control calcium entry into cells, crucial for non-excitable cell function. This review details Orai structures and proposes a "push-pull" model for calcium permeation through these CRAC channels.
Area of Science:
- Biophysics
- Molecular Biology
- Cell Physiology
Background:
- Orai channels are key components of the calcium release-activated calcium (CRAC) channel family.
- They mediate essential extracellular Ca2+ influx triggered by endoplasmic reticulum Ca2+ depletion in non-excitable cells.
- While Orai channel activation is well-studied, the Ca2+ permeation gating mechanism remains less understood.
Purpose of the Study:
- To review and synthesize existing structural studies of Orai channels.
- To elucidate the structural features and conformational changes of Orai channels between closed and open states.
- To propose a novel model for Ca2+ permeation through Orai channels.
Main Methods:
- Comprehensive literature review of structural studies on Orai channels.
- Analysis of structural data comparing closed and open Orai channel conformations.
- Development of a mechanistic model based on structural insights.
Main Results:
- Detailed description of the structural characteristics of Orai channels.
- Comparison of structural differences between the closed and open states, highlighting key conformational changes.
- Proposal of a "push-pull" model to explain the mechanism of Ca2+ permeation.
Conclusions:
- Structural insights provide a foundation for understanding Orai channel function.
- The proposed "push-pull" model offers a new perspective on the gating mechanism of Ca2+ permeation.
- Further research based on these structural findings can advance the understanding of CRAC channel physiology and disease.
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