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Fine-tuning of store-operated calcium entry by fast and slow Ca2+-dependent inactivation: Involvement of SARAF.

Accepted version
Peer-reviewed

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Article

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Authors

Jardín, Isaac 
Albarran, Letizia 
Salido, Ginés M 
López, Jose J 
Sage, Stewart O 

Abstract

Store-operated Ca2+ entry (SOCE) is a functionally relevant mechanism for Ca2+ influx present in electrically excitable and non-excitable cells. Regulation of Ca2+ entry through store-operated channels is essential to maintain an appropriate intracellular Ca2+ homeostasis and prevent cell damage. Calcium-release activated channels exhibit Ca2+-dependent inactivation mediated by two temporally separated mechanisms: fast Ca2+-dependent inactivation takes effect in the order of milliseconds and involves the interaction of Ca2+ with residues in the channel pore while slow Ca2+-dependent inactivation (SCDI) develops over tens of seconds, requires a global rise in [Ca2+]cyt and is a mechanism regulated by mitochondria. Recent studies have provided evidence that the protein SARAF (SOCE-associated regulatory factor) is involved in the mechanism underlying SCDI of Orai1. SARAF is an endoplasmic reticulum (ER) membrane protein that associates with STIM1 and translocate to plasma membrane-ER junctions in a STIM1-dependent manner upon store depletion to modulate SOCE. SCDI mediated by SARAF depends on the location of the STIM1-Orai1 complex within a PI(4,5)P2-rich microdomain. SARAF also interacts with Orai1 and TRPC1 in cells endogenously expressing STIM1 and cells with a low STIM1 expression and modulates channel function. This review focuses on the modulation by SARAF of SOCE and other forms of Ca2+ influx mediated by Orai1 and TRPC1 in order to provide spatio-temporally regulated Ca2+ signals.

Description

Keywords

Orai1, SARAF, STIM1, Slow Ca(2+)-dependent inactivation, Store-operated calcium entry, Calcium, Calcium Channels, Calcium Signaling, Cell Membrane, Endoplasmic Reticulum, Humans, Intracellular Calcium-Sensing Proteins, Membrane Proteins, Mitochondria, ORAI1 Protein, Stromal Interaction Molecule 1, TRPC Cation Channels

Journal Title

Biochim Biophys Acta Mol Cell Res

Conference Name

Journal ISSN

0167-4889
1879-2596

Volume Title

1865

Publisher

Elsevier BV