17β-Estradiol Inhibits Phosphorylation of STIM1: Implication for Store-Operated Calcium Entry and Chronic Lung Diseases

1. John T. Sheridan, 
2. Rodney C. Gilmore, 
3. Michael J. Watson,
4. Christopher B. Archer and 

1. Robert Tarran*

+Author Affiliations

1. University of North Carolina at Chapel Hill, United States

1. ↵* Corresponding author; email: robert_tarran@med.unc.edu

Capsule

Background: It is unclear how acute exposure to estrogen inhibits Ca²⁺influx and Ca²⁺-activated Cl^- secretion in airway epithelia.

Results: Estrogen inhibited oligomerization and basal phosphorylation of STIM1.

Conclusion: Acute exposure to estrogen inhibits Ca²⁺ influx by disrupting STIM1.

Significance: Knowing how estrogen inhibits Ca²⁺ signaling in the airways increases our understanding of sex-specific differences in lung diseases.

Abstract

Sex plays a significant role in the development of lung diseases including asthma, cancer, chronic bronchitis and cystic fibrosis. In the latter, E2 may inhibit store-operated Ca²⁺ entry (SOCE) to impinge upon airway secretions, leaving females at greater risk of contracting lung infections. Stromal interaction molecule 1 (STIM1)-mediated SOCE is essential for cell homeostasis and regulates numerous processes including cell proliferation, smooth muscle contraction and secretion. 17β-estradiol (E2) can signal non-genomically to modulate Ca²⁺ signaling, but little is known of the underlying mechanisms. We found that E2 exposure inhibited STIM1 translocation in airway epithelia, preventing SOCE. This correlated with a decrease in STIM1-STIM1 FRET and STIM1 mobility in E2-exposed HEK293T cells co-expressing estrogen receptor alpha (ESR1). We also examined the role of STIM1 phosphorylation in E2-mediated inhibition of STIM1 mobility. STIM1 is basally phosphorylated at serine 575, which is required for SOCE. Exposure to E2 significantly decreased STIM1 serine phosphorylation. Mutating serine 575 to an alanine blocked STIM1 phosphorylation, reduced basal STIM1 mobility and rendered STIM1 insensitive to E2. These data indicate that E2 can signal non-genomically by inhibiting basal phosphorylation of STIM1, leading to a reduction in SOCE.

• This Article

  1. First Published onOctober 10, 2013, doi:10.1074/jbc.M113.486662jbc.M113.486662.
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  Received May 17, 2013.
• Accepted October 10, 2013.

• Copyright © 2013, The American Society for Biochemistry and Molecular Biology