title: Unlocking SOAR releases STIM.
abstract: A crucial component of the receptor-evoked Ca(2+) signal is Ca(2+) influx mediated by the store-operated Ca(2+) channels (SOCs). The molecular makeup of one SOC is the endoplasmic reticulum (ER) Ca(2+) sensor STIM1 and the pore-forming Orai1. Ca(2+) release from the ER leads to co-clustering of STIM1 and Orai1 to activate Orai1. The short STIM1 SOAR/CAD domain (STIM1 Orai1-activating region/CRAC-activating domain), which has two coiledcoil (C–C) domains, interacts with the Orai1 C terminus C–C domain to activate the channel. How the function of SOAR is regulated is not known. Korzeniowski et al (2010) and Muik et al (2011; this issue) now identified an autoinhibitory domain in STIM1 that occludes SOAR. Release of SOAR involves a conformational transition that is aided by the Orai1 C–C domain.
authors.affiliation: Department of Pharmacology, Yonsei University, Seoul, Korea.
authors.forename: Joo Young
authors.initials: JY
authors.lastname: Kim
authors.forename: Shmuel
authors.initials: S
authors.lastname: Muallem
mesh_terms: D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism*; D020013:Calcium Signaling / Q000502:physiology*; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000378:metabolism*; D000071740:ORAI1 Protein; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D000071737:Stromal Interaction Molecule 1
chemical_list: D015220:Calcium Channels; D008565:Membrane Proteins; D046912:Multiprotein Complexes; D009363:Neoplasm Proteins; D000071740:ORAI1 Protein; C510746:ORAI1 protein, human; C103530:STIM1 protein, human; D000071737:Stromal Interaction Molecule 1; D002118:Calcium