Atomic force microscopy (AFM) imaging suggests that stromal interaction molecule 1 (STIM1) binds to Orai1 with sixfold symmetry. Issue 17 (1st July 2014)

• Record Type: Journal Article
• Authors: Balasuriya, Dilshan; Srivats, Shyam; Murrell-Lagnado, Ruth D.; Edwardson, J. Michael
• Is Part Of: FEBS letters. Volume 588:Issue 17(2014)
• Page Start: 2874
• Page End: 2880
• Publication Date: 2014-07-01
• Subjects: AFM -- atomic force microscopy -- CRAC -- Ca2+ release-activated Ca2+ channel -- ER -- endoplasmic reticulum -- HA -- hemagglutinin -- PM -- plasma membrane -- PAGE -- polyacrylamide gel electrophoresis -- STIM -- stromal interaction molecule -- SOAR -- STIM1–Orai1 activating region -- Atomic force microscopy -- CRAC channel -- Orai1 -- STIM1 -- Store-operated Ca2+ entry; Biochemistry -- Periodicals; Biophysics -- Periodicals; Molecular biology -- Periodicals; Biochimie -- Périodiques; Biochemistry; Biophysics; Molecular biology; Periodicals; 572.05
• DOI: 10.1016/j.febslet.2014.06.054
• Languages: English
• ISSNs: 0014-5793

Abstract

Abstract : Depletion of Ca 2+ from the endoplasmic reticulum (ER) lumen triggers the opening of Ca 2+ release‐activated Ca 2+ (CRAC) channels at the plasma membrane. CRAC channels are activated by stromal interaction molecule 1 (STIM1), an ER resident protein that senses Ca 2+ store depletion and interacts with Orai1, the pore‐forming subunit of the channel. The subunit stoichiometry of the CRAC channel is controversial. Here we provide evidence, using atomic force microscopy (AFM) imaging, that Orai1 assembles as a hexamer, and that STIM1 binds to Orai1 with sixfold symmetry. STIM1 associates with Orai1 in the form of monomers, dimers, and multimeric string‐like structures that form links between the Orai1 hexamers. Our results provide new insights into the nature of the interactions between STIM1 and Orai1. Abstract : The subunit stoichiometry of the CRAC channel is controversial. AFM imaging shows that Orai1 assembles as a hexamer. STIM1 binds to Orai1 with sixfold symmetry. STIM1 forms string‐like structures that link Orai1 hexamers. Our results provide new insights into the interaction between STIM1 and Orai1.