Phosphorylation of neuronal nitric oxide synthase at Ser847 by CaM-KII in the hippocampus of rat brain after transient forebrain ischemia.
The authors previously demonstrated that Ca2+/calmodulin (CaM)-dependent protein kinase IIalpha (CaM-KIIalpha) can phosphorylate neuronal nitric oxide synthase (nNOS) at Ser847 and attenuate NOS activity in neuronal cells. In the present study, they established that forebrain ischemia causes an increase in the phosphorylation of nNOS at Ser847 in the hippocampus. This nNOS phosphorylation appeared to be catalyzed by CaM-KII: (1) it correlated with the autophosphorylation of CaM-KIIalpha; (2) it was blocked by the CaM-KII inhibitor, KN-93; and (3) nNOS and CaM-KIIalpha were found to coexist in the hippocampus. Examination of the spatial relation between nNOS and CaM-KIIalpha in the brain revealed coexistence in the hippocampus but not in the cortex during reperfusion, with a concomitant increase in autophosphorylation of CaM-KIIalpha. The phosphorylation of nNOS at Ser847 probably takes place in nonpyramidal hippocampal neurons, which increased after 30 minutes of reperfusion in the hippocampus, whereas no significant increase was detected in the cortex. An intraventricular injection of KN-93 significantly decreased the phosphorylation of nNOS in the hippocampus. These results point to CaM-KII as a protein kinase, which by its colocalization may attenuate the activity of nNOS through its Ser847 phosphorylation, and may thus contribute to promotion of tolerance to postischemic damage in hippocampal neurons.
Osuka
Koji
K
Department of Neurosurgery, Nagoya University Graduate School of Medicine, Japan.
Watanabe
Yasuo
Y
Usuda
Nobuteru
N
Nakazawa
Ayami
A
Fukunaga
Kohji
K
Miyamoto
Eishichi
E
Takayasu
Masakazu
M
Tokuda
Masaaki
M
Yoshida
Jun
J
D000818:Animals; D001596:Benzylamines / Q000494:pharmacology; D001794:Blood Pressure; D001831:Body Temperature; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002245:Carbon Dioxide / Q000097:blood; D004195:Disease Models, Animal; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007839:Functional Laterality; D006624:Hippocampus / Q000201:enzymology*; D007276:Injections, Intraventricular; D002546:Ischemic Attack, Transient / Q000097:blood / Q000201:enzymology* / Q000503:physiopathology; D008297:Male; D019001:Nitric Oxide Synthase / Q000737:chemistry / Q000378:metabolism*; D052248:Nitric Oxide Synthase Type I; D010100:Oxygen / Q000097:blood; D010766:Phosphorylation; D010768:Phosphoserine; D047428:Protein Kinase Inhibitors; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values; D015424:Reperfusion; D013449:Sulfonamides / Q000494:pharmacology; D013997:Time Factors; D000096926:Benzenesulfonamides
D001596:Benzylamines; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002245:Carbon Dioxide; D004791:Enzyme Inhibitors; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; D010100:Oxygen; D010768:Phosphoserine; D047428:Protein Kinase Inhibitors; D013449:Sulfonamides; C072105:KN 93; D000096926:Benzenesulfonamides; C496322:Nos1 protein, rat; C517675:Camk2a protein, rat