DAPK catalytic activity in the hippocampus increases during the recovery phase in an animal model of brain hypoxic-ischemic injury.
Death-associated protein kinase (DAPK) is a pro-apoptotic, calmodulin (CaM)-regulated protein kinase whose mRNA levels increase following cerebral ischemia. However, the relationship between DAPK catalytic activity and cerebral ischemia is not known. This knowledge is critical as DAPK function is dependent on the catalytic activity of its kinase domain. Consequently, we examined DAPK catalytic activity in a rat model of neonatal cerebral hypoxia-ischemia (HI). An increase in DAPK specific activity was found in homogenates of the hippocampus from the injured right hemisphere, compared to the uninjured left hemisphere, 7 days after injury. The results raised the possibility that an upregulation of DAPK activity might be associated with the recovery phase of HI, during which neuronal repair and differentiation are initiated. Therefore, we examined the change of DAPK in an experimentally tractable cell culture model of neuronal differentiation. We found that DAPK catalytic activity and protein levels increase after nerve growth factor (NGF)-induced differentiation of rat PC12 cells. These results suggest that DAPK may have a previously unappreciated role in neuronal development or recovery from injury, and that potential future therapies targeting DAPK should consider a restricted time window.
Schumacher
Andrew M
AM
Drug Discovery Program, Northwestern University, Chicago, IL 60614, USA.
Velentza
Anastasia V
AV
Watterson
D Martin
DM
Wainwright
Mark S
MS
D000818:Animals; D000831:Animals, Newborn; D051017:Apoptosis Regulatory Proteins; D001665:Binding Sites; D001921:Brain / Q000201:enzymology / Q000473:pathology; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D002384:Catalysis; D002454:Cell Differentiation; D064550:Death-Associated Protein Kinases; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology; D006624:Hippocampus / Q000201:enzymology*; D020925:Hypoxia-Ischemia, Brain / Q000175:diagnosis / Q000201:enzymology* / Q000473:pathology; D007700:Kinetics; D008958:Models, Molecular; D020932:Nerve Growth Factor / Q000494:pharmacology; D016716:PC12 Cells; D051381:Rats; D017208:Rats, Wistar; D015854:Up-Regulation
D051017:Apoptosis Regulatory Proteins; D004791:Enzyme Inhibitors; D020932:Nerve Growth Factor; D064550:Death-Associated Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases