Cerebral ischemia immediately increases serine phosphorylation of the synaptic RAS-GTPase activating protein SynGAP by calcium/calmodulin-dependent protein kinase II alpha in hippocampus of rats

Abstract

The interaction between translocated calcium/calmdulin-dependent protein kinase IIalpha (CaMK IIalpha) and SynGAP during brain ischemia was investigated by Western blotting and immunoprecipitation. Brain ischemia was induced by the four-vessel occlusion method on Sprague-Dawley rats. After 3 min global ischemia, both the binding of CaMK IIalpha to SynGAP and the serine phosphorylation of SynGAP all dramatically increased. Administrating KN-62 through cerebral ventricle (20 min before ischemia) not only remarkably decreased the binding of CaMK IIalpha to SynGAP but also attenuate the elevated serine phosphorylation of SynGAP following 20 min ischemia in hippocampus. These results suggest that CaMK IIalpha is responsible for the serine phosphorylation of SynGAP and a consequent phosphorylation and inhibition of SynGAP may result in activation of mitogen-activated protein kinase pathway which could serve a protective function in brain ischemia.