title: STIM1L is a new actin-binding splice variant involved in fast repetitive Ca2+ release.
abstract: Cytosolic Ca(2+) signals encoded by repetitive Ca(2+) releases rely on two processes to refill Ca(2+) stores: Ca(2+) reuptake from the cytosol and activation of a Ca(2+) influx via store-operated Ca(2+) entry (SOCE). However, SOCE activation is a slow process. It is delayed by >30 s after store depletion because stromal interaction molecule 1 (STIM1), the Ca(2+) sensor of the intracellular stores, must form clusters and migrate to the membrane before being able to open Orai1, the plasma membrane Ca(2+) channel. In this paper, we identify a new protein, STIM1L, that colocalizes with Orai1 Ca(2+) channels and interacts with actin to form permanent clusters. This property allowed the immediate activation of SOCE, a characteristic required for generating repetitive Ca(2+) signals with frequencies within seconds such as those frequently observed in excitable cells. STIM1L was expressed in several mammalian tissues, suggesting that many cell types rely on this Ca(2+) sensor for their Ca(2+) homeostasis and intracellular signaling.
authors.affiliation: Department of Clinical Neurosciences, University Hospital of Geneva, University of Geneva, CH-1211 Geneva 4, Switzerland. basile.darbellay@unige.ch
authors.forename: Basile
authors.initials: B
authors.lastname: Darbellay
authors.forename: Serge
authors.initials: S
authors.lastname: Arnaudeau
authors.forename: Charles R
authors.initials: CR
authors.lastname: Bader
authors.forename: Stephane
authors.initials: S
authors.lastname: Konig
authors.forename: Laurent
authors.initials: L
authors.lastname: Bernheim
mesh_terms: D000199:Actins / Q000378:metabolism*; D017398:Alternative Splicing / Q000235:genetics*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism; D002478:Cells, Cultured; D005091:Exons / Q000235:genetics; D006801:Humans; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D000071740:ORAI1 Protein; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D000071737:Stromal Interaction Molecule 1
chemical_list: D000199:Actins; D015220:Calcium Channels; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D009363:Neoplasm Proteins; D000071740:ORAI1 Protein; C520430:Orai1 protein, mouse; D020033:Protein Isoforms; C103530:STIM1 protein, human; C100757:Stim1 protein, mouse; D000071737:Stromal Interaction Molecule 1; D002118:Calcium