Bcl-2 phosphorylation in the BH4 domain precedes caspase-3 activation and cell death after neonatal cerebral hypoxic-ischemic injury.
To date, there are very few in vivo studies addressing the role of Bcl-2 phosphorylation. In a model of neonatal hypoxic-ischemic (HI) brain injury, we characterized the spatial and temporal phosphorylation of Bcl-2 at serine-24 (PS24-Bcl-2), using a site-specific antibody. Very few cells positive for PS24-Bcl-2 were found in control animals, but the number increased during reperfusion in all investigated brain areas in the ipsilateral hemisphere after HI, particularly in the border region between intact and damaged tissue. The highest numbers were encountered 24 h post-HI. Phosphorylation of Bcl-2 at serine-24 coincided with cytochrome c release after hypoxia-ischemia and preceded caspase-3 activation. Injured neurons displayed a predominantly nuclear, but also mitochondrial, localization of PS24-Bcl-2 immunoreactivity. In conclusion, phosphorylation of Bcl-2 at serine 24 was induced by hypoxia-ischemia, presumably resulting in loss of its anti-apoptotic function.
Hallin
Ulrika
U
Perinatal Center, Department of Physiology, Göteborg University, PO Box 432, SE 405 30 Göteborg, Sweden.
Kondo
Eisaku
E
Ozaki
Yasuhiko
Y
Hagberg
Henrik
H
Shibasaki
Futoshi
F
Blomgren
Klas
K
D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000502:physiology*; D015415:Biomarkers; D015153:Blotting, Western; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism*; D004195:Disease Models, Animal; D004789:Enzyme Activation / Q000502:physiology; D005260:Female; D005455:Fluorescent Antibody Technique; D020925:Hypoxia-Ischemia, Brain / Q000503:physiopathology*; D008297:Male; D009474:Neurons / Q000378:metabolism / Q000473:pathology; D010766:Phosphorylation; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012694:Serine / Q000737:chemistry / Q000276:immunology / Q000378:metabolism
D015415:Biomarkers; D019253:Proto-Oncogene Proteins c-bcl-2; D012694:Serine; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases