Coxsackievirus B3 proteases 2A and 3C induce apoptotic cell death through mitochondrial injury and cleavage of eIF4GI but not DAP5/p97/NAT1.
By transfection of Coxsackievirus B3 (CVB3) individual protease gene into HeLa cells, we demonstrated that 2A(pro) and 3C(pro) induced apoptosis through multiple converging pathways. Firstly, both 2A(pro) and 3C(pro) induced caspase-8-mediated activation of caspase-3 and dramatically reduced cell viability. Secondly, they both activated the intrinsic mitochondria-mediated apoptosis pathway leading to cytochrome c release from mitochondria and activation of caspase-9. However, 3C(pro) induced these events via both up-regulation of Bax and cleavage of Bid, and 2A(pro) induced these events via cleavage of Bid only. Nevertheless, neither altered Bcl-2 expression. Thirdly, both proteases induced cell death through cleavage or down regulation of cellular factors for translation and transcription: both 2A(pro) and 3C(pro) cleaved eukaryotic translation initiation factor 4GI but their cleavage products are different, indicating different cleavage sites; further, both 2A(pro) and 3C(pro) down-regulated cyclic AMP responsive element binding protein, a transcription factor, with 2A(pro) exhibiting a stronger effect than 3C(pro). Surprisingly, neither could cleave DAP5/p97/NAT1, a translation regulator, although this cleavage was observed during CVB3 infection and could not be blocked by caspase inhibitor z-VAD-fmk. Taken together, these data suggest that 2A(pro) and 3C(pro) induce apoptosis through both activation of proapoptotic mediators and suppression of translation and transcription.
Chau
David H W
DH
Department of Pathology and Laboratory Medicine, The James Hogg iCAPTURE Centre, University of British Columbia, St. Paul's Hospital, Room 166, 1081 Burrard Street, Vancouver, BC, Canada.
Yuan
Ji
J
Zhang
Huifang
H
Cheung
Paul
P
Lim
Travis
T
Liu
Zhen
Z
Sall
Alhousseynou
A
Yang
Decheng
D
D000086042:3C Viral Proteases; D000328:Adult; D017209:Apoptosis / Q000502:physiology*; D051023:BH3 Interacting Domain Death Agonist Protein / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D061945:Caspase Inhibitors; D048430:Cell Shape; D002648:Child; D003546:Cysteine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D045304:Cytochromes c / Q000378:metabolism; D004789:Enzyme Activation; D039603:Eukaryotic Initiation Factor-4G / Q000235:genetics / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008928:Mitochondria / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*; D051028:bcl-2-Associated X Protein / Q000378:metabolism
D051023:BH3 Interacting Domain Death Agonist Protein; D061945:Caspase Inhibitors; C113920:EIF4G1 protein, human; C491300:EIF4G2 protein, human; D039603:Eukaryotic Initiation Factor-4G; D019253:Proto-Oncogene Proteins c-bcl-2; D014764:Viral Proteins; D051028:bcl-2-Associated X Protein; D045304:Cytochromes c; D053453:Caspase 9; D003546:Cysteine Endopeptidases; D000086042:3C Viral Proteases; C057400:picornain 2A, Picornavirus