The endogenous inhibitor of Akt, CTMP, is critical to ischemia-induced neuronal death.
Dysregulation of Akt signaling is important in a broad range of diseases that includes cancer, diabetes and heart disease. The role of Akt signaling in brain disorders is less clear. We found that global ischemia in intact rats triggered expression and activation of the Akt inhibitor CTMP (carboxyl-terminal modulator protein) in vulnerable hippocampal neurons and that CTMP bound and extinguished Akt activity and was essential to ischemia-induced neuronal death. Although ischemia induced a marked phosphorylation and nuclear translocation of Akt, phosphorylated Akt was not active in post-ischemic neurons, as assessed by kinase assays and phosphorylation of the downstream targets GSK-3beta and FOXO3A. RNA interference-mediated depletion of CTMP in a clinically relevant model of stroke restored Akt activity and rescued hippocampal neurons. Our results indicate that CTMP is important in the neurodegeneration that is associated with stroke and identify CTMP as a therapeutic target for the amelioration of hippocampal injury and cognitive deficits.
Dominick P. Purpura Department of Neuroscience, Rose F. Kennedy Center, Albert Einstein College of Medicine, Bronx, New York, USA.
Takahiro
T
Miyawaki
Dimitry
D
Ofengeim
Kyung-Min
KM
Noh
Adrianna
A
Latuszek-Barrantes
Brian A
BA
Hemmings
Antonia
A
Follenzi
R Suzanne
RS
Zukin
D021581:Active Transport, Cell Nucleus / Q000502:physiology; D000818:Animals; D020520:Brain Infarction / Q000378:metabolism* / Q000503:physiopathology; D002545:Brain Ischemia / Q000378:metabolism* / Q000503:physiopathology; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D004195:Disease Models, Animal; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors / Q000378:metabolism; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D006624:Hippocampus / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D009410:Nerve Degeneration / Q000378:metabolism* / Q000503:physiopathology; D009474:Neurons / Q000378:metabolism; D010170:Palmitoyl-CoA Hydrolase; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000502:physiology
C541471:CTMP protein, rat; D002352:Carrier Proteins; C499515:FOXO3 protein, rat; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors; D000071679:Glycogen Synthase Kinase 3 beta; C000605507:Gsk3b protein, mouse; C000605508:Gsk3b protein, rat; D051057:Proto-Oncogene Proteins c-akt; D038362:Glycogen Synthase Kinase 3; C527670:CTMP protein, mouse; D010170:Palmitoyl-CoA Hydrolase