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Contribution of TRPC1 and Orai1 to Ca(2+) entry activated by store depletion.
Adv Exp Med Biol. 2011; 704:435-49.AE

Abstract

Store-operated Ca(2+) entry (SOCE) is activated in response to depletion of the ER-Ca(2+) stores by the ER Ca(2+) sensor protein, STIM1 which oligomerizes and moves to ER/PM junctional domains where it interacts with and activates channels involved in SOCE. Two types of channel activities have been described. I(CRAC), via Ca(2+) release-activated Ca(2+) (CRAC) channel, which displays high Ca(2+) selectivity and accounts for the SOCE and cell function in T lymphocytes, mast cells, platelets, and some types of smooth muscle and endothelial cells. Orai1 has been established as the pore-forming component of CRAC channels and interaction of Orai1 with STIM1 is sufficient for generation of the CRAC channel. Store depletion also leads to activation of relatively non-selective cation currents (referred to as I(SOC)) that contribute to SOCE in several other cell types. TRPC channels, including TRPC1, TRPC3, and TRPC4, have been proposed as possible candidate channels for this Ca(2+) influx. TRPC1 is the best characterized channel in this regard and reported to contribute to endogenous SOCE in many cells types. TRPC1-mediated Ca(2+) entry and cation current in cells stimulated with agonist or thapsigargin are inhibited by low [Gd(3+)] and 10-20 μM 2APB (conditions that block SOCE). Importantly, STIM1 also associates with and gates TRPC1 via electrostatic interaction between STIM1 ((684)KK(685)) and TRPC1 ((639)DD(640)). Further, store depletion induces dynamic recruitment of a TRPC1/STIM1/Orai1 complex and knockdown of Orai1 completely abrogates TRPC1 function. Despite these findings, there has been much debate regarding the activation of TRPC1 by store depletion as well as the role of Orai1 and STIM1 in SOC channel function. This chapter summarizes recent studies and concepts regarding the contributions of Orai1 and TRPC1 to SOCE. Major unresolved questions regarding functional interaction between Orai1 and TRPC1 as well as possible mechanisms involved in the regulation of TRPC channels by store depletion will be discussed.

Authors+Show Affiliations

Secretory Physiology Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD 20892, USA. chengo@mail.nih.govNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Review

Language

eng

PubMed ID

21290310

Citation

Cheng, Kwong Tai, et al. "Contribution of TRPC1 and Orai1 to Ca(2+) Entry Activated By Store Depletion." Advances in Experimental Medicine and Biology, vol. 704, 2011, pp. 435-49.
Cheng KT, Ong HL, Liu X, et al. Contribution of TRPC1 and Orai1 to Ca(2+) entry activated by store depletion. Adv Exp Med Biol. 2011;704:435-49.
Cheng, K. T., Ong, H. L., Liu, X., & Ambudkar, I. S. (2011). Contribution of TRPC1 and Orai1 to Ca(2+) entry activated by store depletion. Advances in Experimental Medicine and Biology, 704, 435-49. https://doi.org/10.1007/978-94-007-0265-3_24
Cheng KT, et al. Contribution of TRPC1 and Orai1 to Ca(2+) Entry Activated By Store Depletion. Adv Exp Med Biol. 2011;704:435-49. PubMed PMID: 21290310.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Contribution of TRPC1 and Orai1 to Ca(2+) entry activated by store depletion. AU - Cheng,Kwong Tai, AU - Ong,Hwei Ling, AU - Liu,Xibao, AU - Ambudkar,Indu S, PY - 2011/2/4/entrez PY - 2011/2/4/pubmed PY - 2011/7/2/medline SP - 435 EP - 49 JF - Advances in experimental medicine and biology JO - Adv. Exp. Med. Biol. VL - 704 N2 - Store-operated Ca(2+) entry (SOCE) is activated in response to depletion of the ER-Ca(2+) stores by the ER Ca(2+) sensor protein, STIM1 which oligomerizes and moves to ER/PM junctional domains where it interacts with and activates channels involved in SOCE. Two types of channel activities have been described. I(CRAC), via Ca(2+) release-activated Ca(2+) (CRAC) channel, which displays high Ca(2+) selectivity and accounts for the SOCE and cell function in T lymphocytes, mast cells, platelets, and some types of smooth muscle and endothelial cells. Orai1 has been established as the pore-forming component of CRAC channels and interaction of Orai1 with STIM1 is sufficient for generation of the CRAC channel. Store depletion also leads to activation of relatively non-selective cation currents (referred to as I(SOC)) that contribute to SOCE in several other cell types. TRPC channels, including TRPC1, TRPC3, and TRPC4, have been proposed as possible candidate channels for this Ca(2+) influx. TRPC1 is the best characterized channel in this regard and reported to contribute to endogenous SOCE in many cells types. TRPC1-mediated Ca(2+) entry and cation current in cells stimulated with agonist or thapsigargin are inhibited by low [Gd(3+)] and 10-20 μM 2APB (conditions that block SOCE). Importantly, STIM1 also associates with and gates TRPC1 via electrostatic interaction between STIM1 ((684)KK(685)) and TRPC1 ((639)DD(640)). Further, store depletion induces dynamic recruitment of a TRPC1/STIM1/Orai1 complex and knockdown of Orai1 completely abrogates TRPC1 function. Despite these findings, there has been much debate regarding the activation of TRPC1 by store depletion as well as the role of Orai1 and STIM1 in SOC channel function. This chapter summarizes recent studies and concepts regarding the contributions of Orai1 and TRPC1 to SOCE. Major unresolved questions regarding functional interaction between Orai1 and TRPC1 as well as possible mechanisms involved in the regulation of TRPC channels by store depletion will be discussed. SN - 0065-2598 UR - https://www.unboundmedicine.com/medline/citation/21290310/Contribution_of_TRPC1_and_Orai1_to_Ca_2+__entry_activated_by_store_depletion_ L2 - https://dx.doi.org/10.1007/978-94-007-0265-3_24 DB - PRIME DP - Unbound Medicine ER -