The carboxyl-terminal activation domain of the STAT-1 transcription factor enhances ischemia/reperfusion-induced apoptosis in cardiac myocytes.
We have demonstrated previously that the STAT-1 transcription factor plays a key role in ischemia/reperfusion (I/R)-induced apoptosis in cardiac myocytes. In the present study we assessed which region of the STAT-1 molecule mediates apoptosis in cardiac myocytes. A STAT-1 construct (amino acid 350-750) lacking the N-terminus could enhance I/R-induced apoptosis in cardiac myocytes. However, a STAT-1 construct, which lacks 60 amino acids at the C-terminus (amino acid 691-750), was ineffective in promoting I/R-induced apoptosis in cardiac myocytes. Furthermore, overexpression of a C-terminal STAT-1 construct (amino acid 691-750) containing the transcriptional activation domain, but not the DNA binding domain, strongly enhanced I/R-induced apoptotic cell death. Cardiac myocytes isolated from mice expressing a truncated C-terminal STAT-1 were more sensitive to I/R-induced cell death. Finally, isolated hearts from these animals exposed to I/R injury had larger infarct size and greater number of TUNEL-positive myocytes than control hearts. These studies demonstrate that the C-terminal transactivation domain of STAT-1 is necessary and sufficient for I/R injury-induced apoptosis in cardiac myocytes.
Stephanou
Anastasis
A
Medical Molecular Biology Unit, Institute of Child Health, University College London, London WC1N 1EH, UK. a.stephanou@ich.ucl.ac.uk
Scarabelli
Tiziano M
TM
Townsend
Paul A
PA
Bell
Robert
R
Yellon
Derek
D
Knight
Richard A
RA
Latchman
David S
DS
D000818:Animals; D000831:Animals, Newborn; D017209:Apoptosis / Q000502:physiology*; D001665:Binding Sites / Q000235:genetics; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D005838:Genotype; D020287:In Situ Nick-End Labeling; D051379:Mice; D018345:Mice, Knockout; D009203:Myocardial Infarction / Q000235:genetics / Q000473:pathology; D015428:Myocardial Reperfusion Injury / Q000503:physiopathology*; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D010446:Peptide Fragments / Q000235:genetics; D010766:Phosphorylation; D050794:STAT1 Transcription Factor; D012694:Serine / Q000378:metabolism; D015534:Trans-Activators / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D014162:Transfection
D004268:DNA-Binding Proteins; D010446:Peptide Fragments; D050794:STAT1 Transcription Factor; C494080:Stat1 protein, mouse; D015534:Trans-Activators; D012694:Serine