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The Basal Phosphorylation Sites of Endothelial Nitric Oxide Synthase at Serine (Ser) 1177 , Ser 116 , and Threonine (Thr) 495 in Rat Molar Epithelial Rests of Malassez
Author(s) -
Korkmaz Yüksel,
Bloch Wilhelm,
Addicks Klaus,
Schneider Kurt,
Baumann Michael A.,
Raab Wolfgang H.M.
Publication year - 2005
Publication title -
journal of periodontology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.036
H-Index - 156
eISSN - 1943-3670
pISSN - 0022-3492
DOI - 10.1902/jop.2005.76.9.1513
Subject(s) - enos , phosphorylation , nitric oxide synthase , medicine , chemistry , serine , endocrinology , nitric oxide , nitric oxide synthase type iii , threonine , endothelial nitric oxide synthase , biochemistry , biology
Background: The epithelial rests of Malassez (ERM) are derived from the Hertwig's epithelial root sheath during tooth development. The ERM contain endothelial nitric oxide synthase (eNOS), but the existence of phosphorylation site/s of eNOS in the ERM is unclear. Methods: Rat molars with periodontium were perfusion‐ and post‐fixed, decalcified, and frozen‐sectioned. Free‐floating sections were incubated using antisera against total eNOS, eNOS phosphorylated at serine (Ser) 1177 , Ser 116 , and threonine (Thr) 495 . The signal intensities of t‐eNOS, p‐eNOS at Ser 1177 and Ser 116 in the ERM were measured by densitometry and statistically analyzed. Results: In the ERM, localization of total eNOS and the phosphorylation sites of eNOS at Ser 1177 and Ser 116 were detected, while a basal localization of eNOS phosphorylated at Thr 495 in the ERM was undetectable. For p‐eNOS at Ser 116 regional differences in phosphorylation were detected. Conclusions: The basal production of NO by eNOS in the ERM is modulated by phosphorylation of eNOS at Ser 1177 and Ser 116 residues, while the basal activity of the eNOS is not influenced by phosphorylation of eNOS at Thr 495 residue. This provides evidence that phosphorylation plays a key role for regulation of the catalytic activity of eNOS. J Periodontol 2005;76:1513‐1519 .