Dynamic reconfiguration of pro-apoptotic BAK on membranes
- Sandow, JJ; Tan, IK; Huang, AS; Masaldan, S; Bernardini, JP; Wardak, AZ; Birkinshaw, RW; Ninnis, RL; LIU, Z; Dalseno, D; Lio, D; Infusini, G; Czabotar, PE; Webb, AI; Dewson, G;
- Journal Title
- EMBO Journal
- 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.
- Embo Press
- WEHI Research Division(s)
- Advanced Technology And Biology; Structural Biology; Ubiquitin Signalling
- PubMed ID
- Publisher's Version
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- Refer to copyright notice on published article.
Creation Date: 2021-09-17 11:23:24Last Modified: 2021-09-17 11:58:17