Direct Inhibition of the Conformational Activation of Pro-Apoptotic BAX by the BH4 Domain Helix of BCL-2
View/ Open
Barclay_gsas.harvard.inactive_0084L_11795.pdf (43.10Mb)
Access Status
Full text of the requested work is not available in DASH at this time ("restricted access"). For more information on restricted deposits, see our FAQ.Author
Metadata
Show full item recordCitation
Barclay, Lauren Anne. 2014. Direct Inhibition of the Conformational Activation of Pro-Apoptotic BAX by the BH4 Domain Helix of BCL-2. Doctoral dissertation, Harvard University.Abstract
Programmed cell death by apoptosis is required for normal development and tissue homeostasis. Perturbations of the critical signaling pathways that regulate apoptosis drive a number of pathologic diseases; therefore, a deep understanding of the apoptotic regulatory networks and methods for therapeutically modulating them is highly warranted. As constituents of the intrinsic pathway of apoptosis, pro-apoptotic BCL-2 family proteins respond to internal signals of cell stress to activate cell death through permeabilization of the outer mitochondrial membrane to release cytochrome c and other apoptogenic factors. Anti-apoptotic BCL-2 proteins block apoptosis by forming stable heterodimers with pro-apoptotic BAX and BAK. Specifically, the C-terminal binding groove of BCL-2 sequesters the BCL-2 homology 3 (BH3) death domain of BAX to prevent BAX oligomerization. The N-terminal BH4 domain of BCL-2 is also believed to confer anti-apoptotic activity but the mechanism by which this occurs remains unknown. A direct, inhibitory interaction between the BCL-2 BH4 domain and BAX was established through application of a peptide stapling technology to preserve the α-helical character of the BH4 domain outside the context of full-length BCL-2. Photoaffinity labeling identified a new mode of BH4 domain interaction at the C-terminal face of BAX, revealing an additional layer of apoptotic regulation. Examination of the conformational activation of full-length BAX in a lipid membrane by hydrogen-deuterium exchange mass spectrometry revealed that the BCL-2 BH4 helix blocks the BAX conformational changes triggered by an activating BH3 peptide to preserve the inactive BAX fold. Thus, the mechanistic paradigm for BCL-2 inhibition of BAX has been expanded to allow future opportunities for modulation of apoptosis by mimicking or inhibiting the BH4 motif.Citable link to this page
http://nrs.harvard.edu/urn-3:HUL.InstRepos:13070041
Collections
- FAS Theses and Dissertations [5815]
Contact administrator regarding this item (to report mistakes or request changes)