CRACM1 multimers form the ion-selective pore of the CRAC channel.

ABSTRACT: Receptor-mediated Ca(2+) release from the endoplasmic reticulum (ER) is often followed by Ca(2+) entry through Ca(2+)-release-activated Ca(2+) (CRAC) channels in the plasma membrane . RNAi screens have identified STIM1 as the putative ER Ca(2+) sensor and CRACM1 (Orai1; ) as the putative store-operated Ca(2+) channel. Overexpression of both proteins is required to reconstitute CRAC currents (I(CRAC); ). We show here that CRACM1 forms multimeric assemblies that bind STIM1 and that acidic residues in the transmembrane (TM) and extracellular domains of CRACM1 contribute to the ionic selectivity of the CRAC-channel pore. Replacement of the conserved glutamate in position 106 of the first TM domain of CRACM1 with glutamine (E106Q) acts as a dominant-negative protein, and substitution with aspar

SUBMITTER: Vig M 

PROVIDER: S-EPMC5685803 | biostudies-literature | 2006 Oct

REPOSITORIES: biostudies-literature