Functional Analysis of Orai1 Concatemers Supports a Hexameric Stoichiometry for the CRAC Channel.

ABSTRACT: Store-operated Ca²⁺ entry occurs through the binding of the endoplasmic reticulum (ER) Ca²⁺ sensor STIM1 to Orai1, the pore-forming subunit of the Ca²⁺ release-activated Ca²⁺ (CRAC) channel. Although the essential steps leading to channel opening have been described, fundamental questions remain, including the functional stoichiometry of the CRAC channel. The crystal structure of Drosophila Orai indicates a hexameric stoichiometry, while studies of linked Orai1 concatemers and single-molecule photobleaching suggest that channels assemble as tetramers. We assessed CRAC channel stoichiometry by expressing hexameric concatemers of human Orai1 and comparing in detail their ionic currents to those of native CRAC channels and channels generated from mo

SUBMITTER: Yen M 

PROVIDER: S-EPMC5103002 | biostudies-literature | 2016 Nov

REPOSITORIES: biostudies-literature