Brain ischaemia transiently activates Ca2+/calmodulin-independent protein kinase II.
The activity of Ca2+/calmodulin-dependent protein kinase II (CaM-KII) during short-term global ischaemia was investigated in the gerbil brain hippocampus and cortex. Ischaemia of 0.5 min duration significantly stimulated Ca(2+)-independent 'autonomous' activity, indicating activation of the first step of intramolecular enzyme phosphorylation just after ischaemia has developed. Prolongation of the ischaemic period up to 5 min inhibited both Ca(2+)-dependent and, to a lesser extent, Ca(2+)-independent activities of CaM-KII. These last events coincide with an extensive translocation of CaM-KII protein from the soluble to the membranous fraction. In effect, in spite of inhibition of total CaM-KII activity, its Ca(2+)-independent, persistently active component can still remain more abundant at specific membrane regions.
Zalewska
T
T
Department of Neurochemistry, Medical Research Center, Polish Academy of Science, Warsaw, Poland.
Domanska-Janik
K
K
D000818:Animals; D015153:Blotting, Western; D002545:Brain Ischemia / Q000201:enzymology*; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002540:Cerebral Cortex / Q000201:enzymology; D004789:Enzyme Activation / Q000502:physiology; D005849:Gerbillinae; D006624:Hippocampus / Q000201:enzymology; D008297:Male
D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases