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Nitric Oxide Enhances NFATc3 Nuclear Import and Decreases Export
Author(s) -
Bettini Layne,
AlbertoniBorghese Florencia,
Majowicz Mónica,
Vidal Norberto,
Bosc Laura Gonzalez
Publication year - 2010
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.24.1_supplement.984.21
Subject(s) - nuclear transport , wortmannin , nitric oxide , nuclear export signal , calcineurin , kinase , activator (genetics) , chemistry , phosphorylation , microbiology and biotechnology , biology , cell nucleus , biochemistry , phosphatidylinositol , medicine , gene , transplantation , organic chemistry
We have previously shown that nitric oxide (NO) enhances NFATc‐mediated aquaporin‐2 (AQP2) promoter activation in MDCK cells. Also, we have shown that elevation of Ca 2+ and NO are required for NFATc3 nuclear accumulation in cerebral artery smooth muscle. Ca 2+ ‐activated calcineurin dephosphorylates NFATc allowing its nuclear import. GSK3, protein kinase A and JNK2 phosphorylate NFATc. The goal of this study was to determine the mechanism by which NO enhances NFAT activity. MDCK cells were transfected with a GFP‐NFATc3 plasmid and nuclear fluorescence intensity was measured over time. To study nuclear import, cells were treated with a Crm‐1 exportin inhibitor, 40 nM leptomicin B, and the Ca 2+ ionophore (NFATc activator), 1 μM ionomycin (Io) ± 0.1 mM NONOate (NO donor). To study export, cells were treated for 1 h with Io and then imaged in the presence of 1 μM cyclosporin A (calcineurin inhibitor) ± 0.1 mM NONOate. NO significantly enhanced Io‐induced NFATc3 nuclear import increasing the Ymax without affecting the K (Ymax= 3.6±0.5 vs. 2.4±0.3, n=5, p<0.05). Also, NO decreased NFATc3 nuclear export by increasing the plateau without affecting the K (Plateau= 0.35±0.03 vs. 0.14±0.03, n=5, p<0.05). Our results suggest that NO enhances NFATc nuclear import and decreases export. Future studies will address if NO via protein kinase G is inhibiting any of the kinases that phosphorylate and inactivate NFATc. Supported by AHA SDG.