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Voltage gating at the selectivity filter of the Ca2+ release-activated Ca2+ channel induced by mutation of the Orai1 protein.
J Biol Chem. 2008 May 30; 283(22):14938-45.JB

Abstract

The Ca(2+) release-activated Ca(2+) (CRAC) channel is a plasma membrane (PM) channel that is uniquely activated when free Ca(2+) level in the endoplasmic reticulum (ER) is substantially reduced. Several small interfering RNA screens identified two membrane proteins, Orai1 and STIM1, to be essential for the CRAC channel function. STIM1 appears to function in the PM and as the Ca(2+) sensor in the ER. Orai1 is forming the pore of the CRAC channel. Despite the recent breakthroughs, a mechanistic understanding of the CRAC channel gating is still lacking. Here we reveal new insights on the structure-function relationship of STIM1 and Orai1. Our data suggest that the cytoplasmic coiled-coil region of STIM1 provides structural means for coupling of the ER membrane to the PM to activate the CRAC channel. We mutated two hydrophobic residues in this region to proline (L286P/L292P) to introduce a kink in the first alpha-helix of the coiled-coil domain. This STIM1 mutant caused a dramatic inhibition of the CRAC channel gating compared with the wild type. Structure-function analysis of the Orai1 protein revealed the presence of intrinsic voltage gating of the CRAC channel. A mutation of Orai1 (V102I) close to the selectivity filter modified CRAC channel voltage sensitivity. Expression of the Orai1(V102I) mutant resulted in slow voltage gating of the CRAC channel by negative potentials. The results revealed that the alteration of Val(102) develops voltage gating in the CRAC channel. Our data strongly suggest the presence of a novel voltage gating mechanism at the selectivity filter of the CRAC channel.

Authors+Show Affiliations

Biology Department, Temple University, College of Science and Technology, Philadelphia, PA 19122, USA. spassova@temple.eduNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, N.I.H., Extramural

Language

eng

PubMed ID

18096706

Citation

Spassova, Maria A., et al. "Voltage Gating at the Selectivity Filter of the Ca2+ Release-activated Ca2+ Channel Induced By Mutation of the Orai1 Protein." The Journal of Biological Chemistry, vol. 283, no. 22, 2008, pp. 14938-45.
Spassova MA, Hewavitharana T, Fandino RA, et al. Voltage gating at the selectivity filter of the Ca2+ release-activated Ca2+ channel induced by mutation of the Orai1 protein. J Biol Chem. 2008;283(22):14938-45.
Spassova, M. A., Hewavitharana, T., Fandino, R. A., Kaya, A., Tanaka, J., & Gill, D. L. (2008). Voltage gating at the selectivity filter of the Ca2+ release-activated Ca2+ channel induced by mutation of the Orai1 protein. The Journal of Biological Chemistry, 283(22), 14938-45.
Spassova MA, et al. Voltage Gating at the Selectivity Filter of the Ca2+ Release-activated Ca2+ Channel Induced By Mutation of the Orai1 Protein. J Biol Chem. 2008 May 30;283(22):14938-45. PubMed PMID: 18096706.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Voltage gating at the selectivity filter of the Ca2+ release-activated Ca2+ channel induced by mutation of the Orai1 protein. AU - Spassova,Maria A, AU - Hewavitharana,Thamara, AU - Fandino,Richard A, AU - Kaya,Asli, AU - Tanaka,Jacqueline, AU - Gill,Donald L, Y1 - 2007/12/20/ PY - 2007/12/22/pubmed PY - 2008/7/18/medline PY - 2007/12/22/entrez SP - 14938 EP - 45 JF - The Journal of biological chemistry JO - J. Biol. Chem. VL - 283 IS - 22 N2 - The Ca(2+) release-activated Ca(2+) (CRAC) channel is a plasma membrane (PM) channel that is uniquely activated when free Ca(2+) level in the endoplasmic reticulum (ER) is substantially reduced. Several small interfering RNA screens identified two membrane proteins, Orai1 and STIM1, to be essential for the CRAC channel function. STIM1 appears to function in the PM and as the Ca(2+) sensor in the ER. Orai1 is forming the pore of the CRAC channel. Despite the recent breakthroughs, a mechanistic understanding of the CRAC channel gating is still lacking. Here we reveal new insights on the structure-function relationship of STIM1 and Orai1. Our data suggest that the cytoplasmic coiled-coil region of STIM1 provides structural means for coupling of the ER membrane to the PM to activate the CRAC channel. We mutated two hydrophobic residues in this region to proline (L286P/L292P) to introduce a kink in the first alpha-helix of the coiled-coil domain. This STIM1 mutant caused a dramatic inhibition of the CRAC channel gating compared with the wild type. Structure-function analysis of the Orai1 protein revealed the presence of intrinsic voltage gating of the CRAC channel. A mutation of Orai1 (V102I) close to the selectivity filter modified CRAC channel voltage sensitivity. Expression of the Orai1(V102I) mutant resulted in slow voltage gating of the CRAC channel by negative potentials. The results revealed that the alteration of Val(102) develops voltage gating in the CRAC channel. Our data strongly suggest the presence of a novel voltage gating mechanism at the selectivity filter of the CRAC channel. SN - 0021-9258 UR - https://www.unboundmedicine.com/medline/citation/18096706/Voltage_gating_at_the_selectivity_filter_of_the_Ca2+_release_activated_Ca2+_channel_induced_by_mutation_of_the_Orai1_protein_ L2 - http://www.jbc.org/cgi/pmidlookup?view=long&pmid=18096706 DB - PRIME DP - Unbound Medicine ER -