The human Orai1 (hOrai1) channel plays a crucial role in extracellular Ca influx and has emerged as an attractive drug target for various diseases. However, the activated structure of the hOrai1 channel assembly within a lipid bilayer remains unknown. In this study, we expressed and purified the hOrai1 channel covalently linked to two SOAR tandems (HOSS). Patch-clamp experiments in whole-cell configuration showed that HOSS is constitutively active. Biochemical characterization confirmed that the purified HOSS channels were successfully incorporated into MSP1E3D1 nanodiscs. Negative staining revealed that the HOSS channels resemble a mushroom, with the body representing the hOrai1 channel and the leg representing the SOAR domain. Surprisingly, 2D analysis of cryo-EM data demonstrated a pentameric assembly of HOSS in a lipid bilayer. Our findings suggest that the hOrai1 channel may assemble into different oligomeric states in response to varying membrane environments.
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http://dx.doi.org/10.1016/j.bbrc.2024.150723 | DOI Listing |
Biochem Biophys Res Commun
November 2024
State Key Laboratory of Medicinal Chemical Biology and College of Life Sciences, Nankai University, 94 Weijin Road, Tianjin, 300071, China. Electronic address:
The human Orai1 (hOrai1) channel plays a crucial role in extracellular Ca influx and has emerged as an attractive drug target for various diseases. However, the activated structure of the hOrai1 channel assembly within a lipid bilayer remains unknown. In this study, we expressed and purified the hOrai1 channel covalently linked to two SOAR tandems (HOSS).
View Article and Find Full Text PDFKorean J Physiol Pharmacol
July 2020
Channelopathy Research Center (CRC), Dongguk University College of Medicine, Korea.
() is a widely used herbal medicine with antiinflammatory properties, but its effects on the ORAI1 channel, which is important in generating intracellular calcium signaling for T cell activation, remain unknown. In this study, we investigated whether 70% ethanolic extract () and its subsequent fractions inhibit ORAI1 and determined which constituents contributed to this effect. Whole-cell patch clamp analysis revealed that (64.
View Article and Find Full Text PDFAm J Chin Med
April 2020
Channelopathy Research Center (CRC), Dongguk University College of Medicine, 32 Dongguk-ro, Ilsan Dong-gu, Goyang, Gyeonggi-do 10326, Republic of Korea.
Intracellular calcium signaling is crucial for type 2 helper T cell and mast cell activation, which is essential for allergic inflammation. It is initiated by antigen-mediated receptor stimulation that triggers store-operated calcium entry (SOCE) via ORAI1 calcium channel. (FM) is widely used to treat allergic diseases such as allergic rhinitis and asthma.
View Article and Find Full Text PDFMol Biol Cell
May 2013
Molecular and Cellular Biology Program, University of Massachusetts, Amherst, MA 01002, USA.
In preparation for fertilization, mammalian oocytes undergo optimization of the mechanisms that regulate calcium homeostasis. Among these changes is the increase in the content of the Ca(2+) stores ([Ca(2+)]ER), a process that requires Ca(2+) influx. Nevertheless, the mechanism(s) that mediates this influx remains obscure, although is known that [Ca(2+)]ER can regulate Ca(2+) influx via store-operated Ca(2+) entry (SOCE).
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