RETRACTED: Proapoptotic BAX and BAK modulate the unfolded protein response by a direct interaction with IRE1alpha.
Accumulation of misfolded protein in the endoplasmic reticulum (ER) triggers an adaptive stress response-termed the unfolded protein response (UPR)-mediated by the ER transmembrane protein kinase and endoribonuclease inositol-requiring enzyme-1alpha (IRE1alpha). We investigated UPR signaling events in mice in the absence of the proapoptotic BCL-2 family members BAX and BAK [double knockout (DKO)]. DKO mice responded abnormally to tunicamycin-induced ER stress in the liver, with extensive tissue damage and decreased expression of the IRE1 substrate X-box-binding protein 1 and its target genes. ER-stressed DKO cells showed deficient IRE1alpha signaling. BAX and BAK formed a protein complex with the cytosolic domain of IRE1alpha that was essential for IRE1alpha activation. Thus, BAX and BAK function at the ER membrane to activate IRE1alpha signaling and to provide a physical link between members of the core apoptotic pathway and the UPR.
Hetz
Claudio
C
Howard Hughes Medical Institute, Dana-Farber Cancer Institute, and Harvard Medical School, Boston, MA 02115, USA. chetz@hsph.harvard.edu
Bernasconi
Paula
P
Fisher
Jill
J
Lee
Ann-Hwee
AH
Bassik
Michael C
MC
Antonsson
Bruno
B
Brandt
Gabriel S
GS
Iwakoshi
Neal N
NN
Schinzel
Anna
A
Glimcher
Laurie H
LH
Korsmeyer
Stanley J
SJ
D000818:Animals; D017209:Apoptosis; D004268:DNA-Binding Proteins / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism* / Q000648:ultrastructure; D000091342:Endoplasmic Reticulum Chaperone BiP; D004722:Endoribonucleases / Q000378:metabolism*; D005786:Gene Expression Regulation; D006360:Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D007668:Kidney / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D008099:Liver / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D008928:Mitochondria / Q000378:metabolism; D018832:Molecular Chaperones / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D010766:Phosphorylation; D017510:Protein Folding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D000071701:Regulatory Factor X Transcription Factors; D015398:Signal Transduction; D051742:Transcription Factor CHOP / Q000378:metabolism; D014157:Transcription Factors; D014415:Tunicamycin / Q000494:pharmacology; D050998:bcl-2 Homologous Antagonist-Killer Protein / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051028:bcl-2-Associated X Protein / Q000235:genetics / Q000378:metabolism*; D019892:eIF-2 Kinase / Q000378:metabolism
D004268:DNA-Binding Proteins; D000091342:Endoplasmic Reticulum Chaperone BiP; D004722:Endoribonucleases; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D009687:Nuclear Proteins; D017346:Protein Serine-Threonine Kinases; D019253:Proto-Oncogene Proteins c-bcl-2; D011994:Recombinant Proteins; D000071701:Regulatory Factor X Transcription Factors; D051742:Transcription Factor CHOP; D014157:Transcription Factors; D014415:Tunicamycin; D050998:bcl-2 Homologous Antagonist-Killer Protein; D051028:bcl-2-Associated X Protein; D019892:eIF-2 Kinase; C494773:Bak1 protein, mouse; C494827:Bax protein, mouse; C510185:Ern1 protein, mouse