Measurement of activities of autophosphorylated/non-autophosphorylate CaMKII
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CaMKII activity was measured utilizing syntideII as a substrate. Purified CaMKII was pre-incubated in the assay mixture (35 mM Hepes-Na ( pH 8.0), 10 mM MgC12, 0.5 μM CaM, 5 μM ATP, 1 mM CaCl2 or 1 mM EGTA, total 25 μL) at 30°C for 2 mins. After this pre-incubation, the protein substrate/radioactive ATP mixture was added to the same test tube and the preparation was further incubated at 30°C, for 5 mins (final assay condition: 35 mM Hepes-Na (pH 8.0), 10 mM MgCl2, 0.125 μM CaCl2, 20 μM syntideII, 11.25 μM [γ-32P] ATP, 10 % DMSO and indicated concentrations of KN-93, supplemented with 0.25 mM CaCl2 and 2 mM EGTA (for autophosphorylated samples) or 0.25 mM EGTA and 2 mM CaCl2 (for nonautophosphorylated samples ), total 100 μL). The reaction was terminated by adding of 25 μL of 100 % (w/v) ice-cold TCA. After centrifugation, 80 μL of the supernatant was applied to phosphocellulose paper. The filters were then washed with 75 mM H3PO4 for 15 mins with continuous agitation. After 4-cycles of washing, the radioactivity retains on the filter paper was quantified in a liquid scintillation counter.
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References:
[1]. Sumi M, Kiuchi K, Ishikawa T, Ishii A, Hagiwara M, Nagatsu T, Hidaka H. The newly synthesized selective Ca2+/calmodulin dependent protein kinase II inhibitor KN-93 reduces dopamine contents in PC12h cells. Biochem Biophys Res Commun. 1991 Dec 31;181(3):968-75.
[2]. Tombes RM, Grant S, Westin EH, Krystal G: G1 cell cycle arrest and apoptosis are induced in NIH 3T3 cells by KN-93, an inhibitor of CaMK-II (the multifunctional Ca2+/CaM kinase). Cell Growth Differ 1995, 6(9):1063-1070.
[3]. Yang X, Wu N, Song L, Liu Z. Intrastriatal injections of KN-93 ameliorates levodopa-induced dyskinesia in a rat model of Parkinson's disease. Neuropsychiatr Dis Treat. 2013;9:1213-20.
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