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The N-terminal portion of autoinhibitory element modulates human endothelial nitric-oxide synthase activity through coordinated controls of phosphorylation at Thr495 and Ser1177
- Source :
- Bioscience Reports, Vol 34, Iss 4, p e00129 (2014)
- Publication Year :
- 2014
- Publisher :
- Portland Press, Biochemical Society, 2014.
-
Abstract
- NO production catalysed by eNOS (endothelial nitric-oxide synthase) plays an important role in the cardiovascular system. A variety of agonists activate eNOS through the Ser1177 phosphorylation concomitant with Thr495 dephosphorylation, resulting in increased ·NO production with a basal level of calcium. To date, the underlying mechanism remains unclear. We have previously demonstrated that perturbation of the AIE (autoinhibitory element) in the FMN-binding subdomain can also lead to eNOS activation with a basal level of calcium, implying that the AIE might regulate eNOS activation through modulating phosphorylation at Thr495 and Ser1177. Here we generated stable clones in HEK-293 (human embryonic kidney 293) cells with a series of deletion mutants in both the AIE (Δ594–604, Δ605–612 and Δ626–634) and the C-terminal tail (Δ14; deletion of 1164–1177). The expression of Δ594–604 and Δ605–612 mutants in non-stimulated HEK-293 cells substantially increased nitrate/nitrite release into the culture medium; the other two mutants, Δ626–634 and Δ1164–1177, displayed no significant difference when compared with WTeNOS (wild-type eNOS). Intriguingly, mutant Δ594–604 showed close correlation between Ser1177 phosphorylation and Thr495 dephosphorylation, and NO production. Our results have indicated that N-terminal portion of AIE (residues 594–604) regulates eNOS activity through coordinated phosphorylation on Ser1177 and Thr495.
Details
- Language :
- English
- ISSN :
- 15734935
- Volume :
- 34
- Issue :
- 4
- Database :
- Directory of Open Access Journals
- Journal :
- Bioscience Reports
- Publication Type :
- Academic Journal
- Accession number :
- edsdoj.241c498cdca44a1fac86a42dcd1640f5
- Document Type :
- article
- Full Text :
- https://doi.org/10.1042/BSR20140079