biostudies-literatureUnknown283(42)Wu ZSigma-1 receptor (sigma-1R) agonists enhance inositol 1,4,5-trisphosphate (IP3)-dependent calcium release from endoplasmic reticulum by inducing dissociation of ankyrin B 220 (ANK 220) from the IP3 receptor (IP3R-3), releasing it from inhibition. MCF-7 breast tumor cells express little or no sigma-1R and were used here to investigate the effect of receptor overexpression and the role of its N- and C-terminal segments in function. We stably expressed intact sigma-1R (amino acids (aa) 1-223; lines 11 and 41), N-fragment (aa 1-100; line K3), or C-fragment (aa 102-223; line sg101). C-fragment expressed as a peripheral membrane-bound protein that was removable from the endoplasmic reticulum membrane by chaotropic salt wash, consistent with lack of a putative transmembrane domain. The expressed The Journal of biological chemistry28198-215https://www.ebi.ac.uk/biostudies/studies/S-EPMC2661391biostudies-literatureRole of sigma-1 receptor C-terminal segment in inositol 1,4,5-trisphosphate receptor activation: constitutive enhancement of calcium signaling in MCF-7 tumor cells.PMC2661391Wu ZBowen WDfalseRole of sigma-1 receptor C-terminal segment in inositol 1,4,5-trisphosphate receptor activation: constitutive enhancement of calcium signaling in MCF-7 tumor cells.Sigma-1 receptor (sigma-1R) agonists enhance inositol 1,4,5-trisphosphate (IP3)-dependent calcium release from endoplasmic reticulum by inducing dissociation of ankyrin B 220 (ANK 220) from the IP3 receptor (IP3R-3), releasing it from inhibition. MCF-7 breast tumor cells express little or no sigma-1R and were used here to investigate the effect of receptor overexpression and the role of its N- and C-terminal segments in function. We stably expressed intact sigma-1R (amino acids (aa) 1-223; lines 11 and 41), N-fragment (aa 1-100; line K3), or C-fragment (aa 102-223; line sg101). C-fragment expressed as a peripheral membrane-bound protein that was removable from the endoplasmic reticulum membrane by chaotropic salt wash, consistent with lack of a putative transmembrane domain. The expressed 2008-01-01T00:00:00Z2008 Oct2025-04-21T17:59:30.593Z2019-03-27T00:21:26ZS-EPMC26613911853959310.1074/jbc.m80209920010.1074/jbc.M802099200