Functional proteins involved in regulation of intracellular Ca(2+) for drug development: role of calcium/calmodulin-dependent protein kinases in ischemic neuronal death.
Excessive elevation of intracellular calcium level seems to be a trigger of ischemic neuronal injury. Calcium/calmodulin (CaM)-dependent protein kinase kinase (CaM-KK) is an upstream kinase for CaM kinase IV (CaM-KIV) that was reported to prevent apoptosis through phosphorylation of CREB (cyclic AMP responsive element-binding protein). We here observed that CaM-KK could directly activate Akt, thereby preventing apoptosis in cultured cells. Then we examined changes in Akt and CaM-KIV activities in gerbil forebrain ischemia. In 5-min-ischemia-caused delayed neuronal death in hippocampal CA1 neurons, Akt and CaM-KIV activities were decreased after reperfusion. On the other hand, during induction of ischemic tolerance, Akt activity gradually and persistently increased in the CA1 neurons with transient increase in CREB phosphorylation. Inhibition of Akt activity with wortmannin or CREB-DNA binding with CRE-decoy injection resulted in failure of generation of ischemic tolerance. These results indicated activation of Akt and CaM-KIV play important roles in induction of the ischemic tolerance. Activation of CaM-KK may provide a new strategy for overcoming the ischemic stress.
Yano
Shigetoshi
S
Department of Neurosurgery, Faculty of Medical and Pharmaceutical Sciences, Kumamoto University Graduate School, Kumamoto. yanos@kaiju.medic.kumamoto-u.ac.jp
Morioka
Motohiro
M
Kuratsu
Jun-Ichi
J
Fukunaga
Kohji
K
D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002545:Brain Ischemia / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D054737:Calcium-Calmodulin-Dependent Protein Kinase Kinase; D054734:Calcium-Calmodulin-Dependent Protein Kinase Type 4; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002460:Cell Line; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D015195:Drug Design; D004789:Enzyme Activation / Q000187:drug effects; D005849:Gerbillinae; D006624:Hippocampus / Q000166:cytology; D019194:Ischemic Preconditioning; D008954:Models, Biological; D009474:Neurons / Q000166:cytology* / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D000077191:Wortmannin
D000730:Androstadienes; D017362:Cyclic AMP Response Element-Binding Protein; D011518:Proto-Oncogene Proteins; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D054737:Calcium-Calmodulin-Dependent Protein Kinase Kinase; D054734:Calcium-Calmodulin-Dependent Protein Kinase Type 4; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002118:Calcium; D000077191:Wortmannin