These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Molecular determinants of fast Ca2+-dependent inactivation and gating of the Orai channels.
    Author: Lee KP, Yuan JP, Zeng W, So I, Worley PF, Muallem S.
    Journal: Proc Natl Acad Sci U S A; 2009 Aug 25; 106(34):14687-92. PubMed ID: 19706554.
    Abstract:
    Ca(2+) influx by store-operated Ca(2+) influx channels (SOCs) mediates many cellular functions regulated by Ca(2+), and excessive SOC-mediated Ca(2+) influx is cytotoxic and associated with disease. One form of SOC is the CRAC current that is mediated by Orai channels activated by STIM1. A fundamental property of the native CRAC and of the Orais is fast Ca(2+)-dependent inactivation, which limits Ca(2+) influx to guard against cellular damage. The molecular mechanism of this essential regulatory mechanism is unknown. We report here the fast Ca(2+)-dependent inactivation is mediated by three conserved glutamates in the C termini (CT) of Orai2 and Orai3, which show prominent fast Ca(2+)-dependent inactivation compared with Orai1. Transfer of the CT between the Orais transfers both the extent of channel opening and the mode of fast Ca(2+)-dependent inactivation. Fast Ca(2+)-dependent inactivation of the Orais also requires a domain of STIM1; fragments of STIM1 that efficiently open Orai channels do not evoke fast inactivation unless they include an anionic sequence that is C-terminal to the STIM1-Orai activating region (SOAR). Our studies suggest that Orai CT are necessary and sufficient to control pore opening and uncover the molecular mechanism of fast Ca(2+)-dependent inactivation that has implications for Ca(2+) influx by SOC in physiological and pathological states.
    [Abstract] [Full Text] [Related] [New Search]