Regulation of the human apoptotic DNase/RNase endonuclease G: involvement of Hsp70 and ATP.
Endonuclease G (EndoG) is a mitochondrial enzyme that becomes an apoptotic nuclease when released from the mitochondrial intermembrane space. EndoG will digest either DNA or RNA, but at physiological ionic strength, RNA is a much more favorable substrate as compared to chromatin. This indicates that EndoG's major in vivo function(s) may be: (i) an apoptotic RNase, and/or (ii) an apoptotic DNase in the presence of additional co-activators. In the present study we have searched for factors that modulate the activity of human EndoG on DNA substrates. We demonstrate that EndoG forms complexes with AIF and FEN-1 but not with PCNA. Interestingly, heat shock proteins 70 interact with EndoG and are involved in the regulation of its activity. Purified Hsp70 prevented stimulation of EndoG DNase activity by other nuclear factors in the ATP-dependent manner.
Kalinowska
M
M
Department of Experimental and Clinical Radiobiology, Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice, Poland.
Garncarz
W
W
Pietrowska
M
M
Garrard
W T
WT
Widlak
P
P
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D051033:Apoptosis Inducing Factor / Q000378:metabolism; D002457:Cell Extracts; D002467:Cell Nucleus / Q000187:drug effects / Q000201:enzymology; D004247:DNA / Q000378:metabolism; D004706:Endodeoxyribonucleases / Q000378:metabolism*; D045585:Flap Endonucleases / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D009687:Nuclear Proteins / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D012260:Ribonucleases / Q000378:metabolism*; D013379:Substrate Specificity / Q000187:drug effects
D051033:Apoptosis Inducing Factor; D002457:Cell Extracts; D018840:HSP70 Heat-Shock Proteins; D009687:Nuclear Proteins; D012313:RNA; D000255:Adenosine Triphosphate; D004247:DNA; D004706:Endodeoxyribonucleases; D045585:Flap Endonucleases; D012260:Ribonucleases; C052391:endonuclease G