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Neuronal nitric oxide synthase inhibits store‐operated Ca 2+ entry in cardiomyocytes via S‐nitrosylation of stromal interaction molecule‐1
Author(s) -
Feng Qingping,
Gui Le,
Zhu Jinhui,
Lu Xiangru,
Sims Stephen M.,
Lu WeiYang,
Stathopulos Peter B.
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.718.2
Subject(s) - stim1 , orai1 , chemistry , microbiology and biotechnology , nitric oxide , nitrosylation , s nitrosylation , endoplasmic reticulum , hek 293 cells , nitric oxide synthase , biophysics , biochemistry , cysteine , biology , receptor , organic chemistry , enzyme
Store‐operated Ca 2+ entry (SOCE) mediated by stromal interacting molecule‐1 (STIM1) and Orai1 represents a major route of Ca 2+ entry in mammalian cells. The luminal domain of STIM1 is critical to Ca 2+ sensing, STIM1 oligomerization and SOCE activation. Notably, the luminal domain contains two cysteine sites (Cys49 and Cys56). It is not known if neuronal nitric oxide synthase (nNOS), which is associated to the sarcoplasmic reticulum (SR) membrane, regulates STIM1 oligomerization and SOCE activity in cardiomyocytes via S‐nitrosylation of these cysteine sites. Here, we show that nNOS deficiency or treatment with a nNOS inhibitor L‐VNIO significantly increased SOCE in cardiomyocytes. Further, the Ca 2+ release‐activated Ca 2+ channel current ( I CRAC ) was significantly enhanced in cardiomyocytes treated with L‐VNIO and in nNOS −/− cardiomyocytes. Consistently, STIM1 S‐nitrosylation was significantly decreased in nNOS −/− hearts. Treatment of HEK293 cells co‐expressing YFP‐Orai1 and mCherry‐STIM1 with the NO donor S‐nitrosoglutathione (GSNO) inhibited STIM1 puncta formation and I CRAC . Remarkably, no functional inhibition was observed in cells expressing the Cys49Ser/Cys56Ser STIM1 double mutant. Mechanistically, we found that NO donors caused Cys49 and Cys56‐specific structural changes associated with reduced protein backbone mobility, significantly increased the thermal stability and suppressed Ca 2+ ‐depletion‐dependent oligomerization of the luminal Ca 2+ ‐sensing region of STIM1. Collectively, our data reveal that nNOS inhibits SOCE in cardiomyocytes through NO‐mediated STIM1 S‐nitrosylation which suppresses oligomerization via enhanced luminal domain stability and rigidity. Support or Funding Information Canadian Institutes of Health Research