Dynamic reconfiguration of pro-apoptotic BAK on membranes.
EMBO J
; 40(20): e107237, 2021 10 18.
Article
in En
| MEDLINE
| ID: mdl-34523147
ABSTRACT
BAK and BAX, the effectors of intrinsic apoptosis, each undergo major reconfiguration to an activated conformer that self-associates to damage mitochondria and cause cell death. However, the dynamic structural mechanisms of this reconfiguration in the presence of a membrane have yet to be fully elucidated. To explore the metamorphosis of membrane-bound BAK, we employed hydrogen-deuterium exchange mass spectrometry (HDX-MS). The HDX-MS profile of BAK on liposomes comprising mitochondrial lipids was consistent with known solution structures of inactive BAK. Following activation, HDX-MS resolved major reconfigurations in BAK. Mutagenesis guided by our HDX-MS profiling revealed that the BCL-2 homology (BH) 4 domain maintains the inactive conformation of BAK, and disrupting this domain is sufficient for constitutive BAK activation. Moreover, the entire N-terminal region preceding the BAK oligomerisation domains became disordered post-activation and remained disordered in the activated oligomer. Removal of the disordered N-terminus did not impair, but rather slightly potentiated, BAK-mediated membrane permeabilisation of liposomes and mitochondria. Together, our HDX-MS analyses reveal new insights into the dynamic nature of BAK activation on a membrane, which may provide new opportunities for therapeutic targeting.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Proto-Oncogene Proteins c-bcl-2
/
Bcl-2 Homologous Antagonist-Killer Protein
/
Liposomes
/
Membrane Lipids
Limits:
Animals
/
Humans
Language:
En
Journal:
EMBO J
Year:
2021
Type:
Article
Affiliation country:
Australia