气候变化领域集成服务门户(CCPortal): Mapping the functional anatomy of Orai1 transmembrane domains for CRAC channel gating

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DOI	10.1073/pnas.1718373115
	Mapping the functional anatomy of Orai1 transmembrane domains for CRAC channel gating
	Yeung P.S.-W.; Yamashita M.; Ing C.E.; Pomès R.; Freymann D.M.; Prakriya M.
发表日期	2018
ISSN	0027-8424
起始页码	E5193
结束页码	E5202
卷号	115 期号:22
英文摘要	Store-operated Orai1 channels are activated through a unique inside-out mechanism involving binding of the endoplasmic reticulum Ca2+ sensor STIM1 to cytoplasmic sites on Orai1. Although atomic-level details of Orai structure, including the pore and putative ligand binding domains, are resolved, how the gating signal is communicated to the pore and opens the gate is unknown. To address this issue, we used scanning mutagenesis to identify 15 residues in transmembrane domains (TMs) 1–4 whose perturbation activates Orai1 channels independently of STIM1. Cysteine accessibility analysis and molecular-dynamics simulations indicated that constitutive activation of the most robust variant, H134S, arises from a pore conformational change that opens a hydrophobic gate to augment pore hydration, similar to gating evoked by STIM1. Mutational analysis of this locus suggests that H134 acts as steric brake to stabilize the closed state of the channel. In addition, atomic packing analysis revealed distinct functional contacts between the TM1 pore helix and the surrounding TM2/3 helices, including one set mediated by a cluster of interdigitating hydrophobic residues and another by alternative ridges of polar and hydrophobic residues. Perturbing these contacts via mutagenesis destabilizes STIM1-mediated Orai1 channel gating, indicating that these bridges between TM1 and the surrounding TM2/3 ring are critical for conveying the gating signal to the pore. These findings help develop a framework for understanding the global conformational changes and allosteric interactions between topologically distinct domains that are essential for activation of Orai1 channels. © 2018 National Academy of Sciences. All rights reserved.
英文关键词	Calcium; CRAC channels; Orai1; STIM1; Store-operated calcium entry
语种	英语
scopus关键词	calcium release activated calcium channel 1; cysteine; stromal interaction molecule 1; calcium; calcium release activated calcium channel 1; ORAI1 protein, human; allosterism; alpha helix; Article; channel gating; conformational transition; functional anatomy; gene cluster; gene locus; hydrophobicity; molecular dynamics; mutagenesis; mutational analysis; priority journal; protein domain; protein function; signal transduction; chemistry; genetics; human; metabolism; protein domain; Calcium; Humans; Molecular Dynamics Simulation; ORAI1 Protein; Protein Domains
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/160506
作者单位	Yeung, P.S.-W., Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States; Yamashita, M., Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States; Ing, C.E., Molecular Medicine, Hospital for Sick Children Research Institute, Toronto, ON M5G 0A4, Canada, Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada; Pomès, R., Molecular Medicine, Hospital for Sick Children Research Institute, Toronto, ON M5G 0A4, Canada, Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A8, Canada; Freymann, D.M., Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States; Prakriya, M., Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States
推荐引用方式 GB/T 7714	Yeung P.S.-W.,Yamashita M.,Ing C.E.,et al. Mapping the functional anatomy of Orai1 transmembrane domains for CRAC channel gating[J],2018,115(22).
APA	Yeung P.S.-W.,Yamashita M.,Ing C.E.,Pomès R.,Freymann D.M.,&Prakriya M..(2018).Mapping the functional anatomy of Orai1 transmembrane domains for CRAC channel gating.Proceedings of the National Academy of Sciences of the United States of America,115(22).
MLA	Yeung P.S.-W.,et al."Mapping the functional anatomy of Orai1 transmembrane domains for CRAC channel gating".Proceedings of the National Academy of Sciences of the United States of America 115.22(2018).