Genetically defining the mechanism of Puma- and Bim-induced apoptosis.
Using genetically modified mouse models, we report here that p53 upregulated modulator of apoptosis (Puma) and Bcl-2 interacting mediator of cell death (Bim), two pro-apoptotic members of the B-cell lymphoma protein-2 (Bcl-2) family of proteins, cooperate in causing bone marrow and gastrointestinal tract toxicity in response to chemo and radiation therapy. Deletion of both Puma and Bim provides long-term survival without evidence of increased tumor susceptibility following a lethal challenge of carboplatin and ionizing radiation. Consistent with these in vivo findings, studies of primary mast cells demonstrated that the loss of Puma and Bim confers complete protection from cytokine starvation and DNA damage, similar to that observed for Bax/Bak double knockout cells. Biochemical analyses demonstrated an essential role for either Puma or Bim to activate Bax, thereby leading to mitochondrial outer membrane permeability, cytochrome c release and apoptosis. Treatment of cytokine-deprived cells with ABT-737, a BH3 mimetic, demonstrated that Puma is sufficient to activate Bax even in the absence of all other known direct activators, including Bim, Bid and p53. Collectively, our results identify Puma and Bim as key mediators of DNA damage-induced bone marrow failure and provide mechanistic insight into how BH3-only proteins trigger cell death.
Department of Biochemistry, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
S P
SP
Garrison
D C
DC
Phillips
J R
JR
Jeffers
J E
JE
Chipuk
M J
MJ
Parsons
J E
JE
Rehg
J T
JT
Opferman
D R
DR
Green
G P
GP
Zambetti
D000741:Anemia, Aplastic; D000818:Animals; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism*; D000072224:Bcl-2-Like Protein 11; D001713:Biphenyl Compounds / Q000494:pharmacology; D001855:Bone Marrow Diseases; D000080983:Bone Marrow Failure Disorders; D002470:Cell Survival / Q000235:genetics; D045304:Cytochromes c / Q000235:genetics / Q000378:metabolism; D004249:DNA Damage; D017353:Gene Deletion; D006457:Hemoglobinuria, Paroxysmal / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D008407:Mast Cells / Q000378:metabolism / Q000473:pathology; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D051336:Mitochondrial Membranes / Q000378:metabolism / Q000473:pathology; D009596:Nitrophenols / Q000494:pharmacology; D010539:Permeability; D010879:Piperazines / Q000494:pharmacology; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D013449:Sulfonamides / Q000494:pharmacology; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism*; D051028:bcl-2-Associated X Protein / Q000235:genetics / Q000378:metabolism*
C501332:ABT-737; D051017:Apoptosis Regulatory Proteins; C494827:Bax protein, mouse; D000072224:Bcl-2-Like Protein 11; C000606776:Bcl2l11 protein, mouse; D001713:Biphenyl Compounds; D008565:Membrane Proteins; D009596:Nitrophenols; C488588:PUMA protein, mouse; D010879:Piperazines; D011518:Proto-Oncogene Proteins; D013449:Sulfonamides; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; D051028:bcl-2-Associated X Protein; D045304:Cytochromes c