The Basal phosphorylation sites of endothelial nitric oxide synthase at serine (Ser)1177, Ser116, and threonine (Thr)495 in rat molar epithelial rests of Malassez.
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, Ser116, and threonine (Thr)495. The signal intensities of t-eNOS, p-eNOS at Ser1177 and Ser116 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 Ser1177 and Ser116 were detected, while a basal localization of eNOS phosphorylated at Thr495 in the ERM was undetectable. For p-eNOS at Ser116 regional differences in phosphorylation were detected.


CONCLUSIONS
The basal production of NO by eNOS in the ERM is modulated by phosphorylation of eNOS at Ser1177 and Ser116 residues, while the basal activity of the eNOS is not influenced by phosphorylation of eNOS at Thr495 residue. This provides evidence that phosphorylation plays a key role for regulation of the catalytic activity of eNOS.
Korkmaz
Yüksel
Y
Department of Operative and Preventive Dentistry and Endodontics, Heinrich-Heine-University, Düsseldorf, Germany. yueksel.korkmaz@uni-duesseldorf.de
Bloch
Wilhelm
W
Addicks
Klaus
K
Schneider
Kurt
K
Baumann
Michael A
MA
Raab
Wolfgang H-M
WH
D000818:Animals; D002417:Cattle; D006041:Goats; D008297:Male; D008963:Molar; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism*; D010513:Periodontal Ligament / Q000166:cytology / Q000201:enzymology; D010519:Periodontium / Q000201:enzymology*; D010766:Phosphorylation; D011817:Rabbits; D051381:Rats; D017208:Rats, Wistar; D012694:Serine / Q000378:metabolism; D013912:Threonine / Q000378:metabolism
D013912:Threonine; D012694:Serine; D052250:Nitric Oxide Synthase Type III