BAK/BAX-mediated mitochondrial outer-membrane permeabilization (MOMP) drives cell death during development and tissue homeostasis from zebrafish to humans. In most cancers, this pathway is inhibited by BCL-2 family antiapoptotic members, which bind a ...
BAK/BAX-mediated mitochondrial outer-membrane permeabilization (MOMP) drives cell death during development and tissue homeostasis from zebrafish to humans. In most cancers, this pathway is inhibited by BCL-2 family antiapoptotic members, which bind and block the action of proapoptotic BCL proteins. We report the 1.5 A crystal structure of calpain-proteolysed BAK, cBAK, to reveal a zinc binding site that regulates its activity via homodimerization. cBAK contains an occluded BH3 peptide binding pocket that binds a BID BH3 peptide only weakly . Nonetheless, cBAK requires activation by truncated BID to induce cytochrome c release in mitochondria isolated from bak/bax double-knockout mouse embryonic fibroblasts. The BAK-mediated MOMP is inhibited by low micromolar zinc levels. This inhibition is alleviated by mutation of the zinc-coordination site in BAK. Our results link directly the antiapoptotic effects of zinc to BAK.
Organizational Affiliation:
Department of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montreal, QC, Canada H3G 1Y6. Electronic address: tudor.moldoveanu@stjude.org.,Department of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montreal, QC, Canada H3G 1Y6; GeminX Biotechnologies, Inc., Place du Parc, Montreal, QC, Canada H2X 4A5.,GeminX Biotechnologies, Inc., Place du Parc, Montreal, QC, Canada H2X 4A5.,Department of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montreal, QC, Canada H3G 1Y6. Electronic address: kalle.gehring@mcgill.ca.,Department of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montreal, QC, Canada H3G 1Y6.
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