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J Cell Sci. 2019 May 15;132(10). pii: jcs226019. doi: 10.1242/jcs.226019.

STIM1 phosphorylation at Y316 modulates its interaction with SARAF and the activation of SOCE and I CRAC.

Author information

1
Department of Physiology, Cell Physiology Research Group, Institute of Molecular Pathology Biomarkers, University of Extremadura, 10003 Caceres, Spain.
2
Molecular & Membrane Biophysics, Institute of Biophysics, Johannes Kepler University Linz, A-4020 Linz, Austria.
3
Department of Medical Physiology and Biophysics, Institute of Biomedicine of Seville (IBiS)/University of Seville/CIBERCV, 41013 Seville, Spain.
4
Department of Physiology, Cell Physiology Research Group, Institute of Molecular Pathology Biomarkers, University of Extremadura, 10003 Caceres, Spain pcr@unex.es.

Abstract

Stromal interaction molecule 1 (STIM1) is one of the key elements for the activation of store-operated Ca2+ entry (SOCE). Hence, identification of the relevant phosphorylatable STIM1 residues with a possible role in the regulation of STIM1 function and SOCE is of interest. By performing a computational analysis, we identified that the Y316 residue is susceptible to phosphorylation. Expression of the STIM1-Y316F mutant in HEK293, NG115-401L and MEG-01 cells resulted in a reduction in STIM1 tyrosine phosphorylation, SOCE and the Ca2+ release-activated Ca2+ current (I CRAC). STIM1-Orai1 colocalization was reduced in HEK293 cells transfected with YFP-STIM1-Y316F compared to in cells with wild-type (WT) YFP-tagged STIM1. Additionally, the Y316F mutation altered the pattern of interaction between STIM1 and SARAF under resting conditions and upon Ca2+ store depletion. Expression of the STIM1 Y316F mutant enhanced slow Ca2+-dependent inactivation (SCDI) as compared to STIM1 WT, an effect that was abolished by SARAF knockdown. Finally, in NG115-401L cells transfected with shRNA targeting SARAF, expression of STIM1 Y316F induced greater SOCE than STIM1 WT. Taken together, our results provide evidence supporting the idea that phosphorylation of STIM1 at Y316 plays a relevant functional role in the activation and modulation of SOCE.

KEYWORDS:

ICRAC; Orai1; SARAF; STIM1; Tyrosine phosphorylation; Y316

PMID:
30975919
DOI:
10.1242/jcs.226019

Conflict of interest statement

Competing interestsThe authors declare no competing or financial interests.

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