The Walter and Eliza Hall Institute of Medical Research

Dr Ruth Kluck

Details

Email: .(JavaScript must be enabled to view this email address)
Division: Molecular Genetics of Cancer

Research Overview

Normal cell turnover occurs via the mitochondrial pathway of apoptotic cell death. This cell death is regulated by the Bcl-2 family of proteins, with either Bak or Bax needed for the crucial step of mitochondrial permeabilisation. We aim to delineate how Bak and Bax become active to form the apoptotic pore in the mitochondrial outer membrane, and how pore formation is blocked by pro-survival Bcl-2 family relatives.

Defining these events at the molecular level will help understand how cells decide to live or die, which is fundamental to our understanding of several pathological conditions including cancer and degenerative diseases.

Two pro-apoptotic members, Bak and Bax, can permeabilise the mitochondrial outer membrane. Members of the Bcl-2 protein family contribute to cancer development and are promising therapeutic targets, but developing such agents requires clarifying further how these proteins commits cells to apoptosis.

We are investigating the molecular mechanisms of apoptotic cell death, with a particular interest in identifying how the Bcl-2 protein family regulates mitochondrial permeabilisation. The crucial step of mitochondrial permeabilisation requires either of the pro-apoptotic Bcl-2 members, Bak or Bax, yet it remains poorly understood how they become active and induce the membrane perforation, and how they are blocked by their pro-survival relatives.

We employ a series of biochemical and cell biology approaches to determine how Bak and Bax change conformation to form the apoptotic pore within the mitochondrial outer membrane. Other analyses aim to clarify how Bak and Bax are held in check by the pro-survival regulators such as Bcl-xL and Mcl-1.

Research Interests

• What are the important conformation changes in Bak and Bax that allow pore formation in mitochondria during apoptosis?
• Bak and Bax regulation by other Bcl-2 family proteins

Selected Publications

1. Westphal D, Dewson G, Czabotar PE, Kluck RM.  Molecular biology of Bax and Bak activation and action.  Biochim Biophys Acta. 2010 Dec. 30 [Epun ahead of print]. PMID: 21195116 [PubMed - as supplied by publisher]
2. Dewson G, Kratina T, Czabotar P, Day CL, Adams JM, Kluck RM.  Bak activation for apoptosis involves oligomerization of dimers via their alpha6 helices.  Mol Cell. 2009 Nov 25;36(4):696-703. PMID 19941828 [PubMed - in process]
3. Dewson G, Kluck RM. Mechanisms by which Bak and Bax permeabilise mitochondria during apoptosis.  J Cell Sci. 2009 Aug 15;122(Pt 16):2801-8.PMID: 19795525 [PubMed - indexed for MEDLINE]
4. Dewson G, Kratina T, Sim HW, Puthalakath H, Adams JM, Colman PM, Kluck RM.  To trigger apoptosis, Bak exposes its BH3 domain and homodimerizes via BH3:groove interactions.  Mol Cell. 2008 May 9;30(3):369-80 PMID: 18471982 [PubMed - in process]
5. Uren RT, Dewson G, Chen L, Coyne SC, Huang DC, Adams JM, Kluck RM.  Mitochondrial permeabilization relies on BH3 ligands engaging multiple prosurvival Bcl-2 relatives, not Bak.  J Cell Biol. 2007 Apr 23;177(2):277-87 PMID: 17452531 [PubMed - indexed for MEDLINE]
6. Willis SN, Fletcher JI, Kaufmann T, van Delft MF, Chen L, Czabotar PE, Ierino H, Lee EF, Fairlie WD, Bouillet P, Strasser A, Kluck RM, Adams JM, Huang DC.  Apoptosis initiated when BH3 ligands engage multiple Bcl-2 homologs, not Bax or Bak.  Science. 2007 Feb 9;315(5813):856-9 PMID: 17289999 [PubMed - indexed for MEDLINE]
7. Uren RT, Dewson G, Bonzon C, Lithgow T, Newmeyer DD, Kluck RM.  Mitochondrial release of pro-apoptotic proteins: electrostatic interactions can hold cytochrome c but not Smac/DIABLO to mitochondrial membranes.  J Biol Chem. 2005 Jan 21;280(3):2266-74 PMID: 15537572 [PubMed - indexed for MEDLINE]
8. Kluck RM, Ellerby LM, Ellerby HM, Naiem S, Yaffe MP, Margoliash E, Bredesen D, Mauk AG, Sherman F, Newmeyer DD.  Determinants of cytochrome c pro-apoptotic activity. The role of lysine 72 trimethylation.  J Biol Chem. 2000 May 26;275(21):16127-33 PMID: 10821864 [PubMed - indexed for MEDLINE]
9. Kluck RM, Esposti MD, Perkins G, Renken C, Kuwana T, Bossy-Wetzel E, Goldberg M, Allen T, Barber MJ, Green DR, Newmeyer DD.  The pro-apoptotic proteins, Bid and Bax, cause a limited permeabilization of the mitochondrial outer membrane that is enhanced by cytosol.  J Cell Biol. 1999 Nov 15;147(4):809-22 PMID: 10562282 [PubMed - indexed for MEDLINE]
10. Kluck RM, Bossy-Wetzel E, Green DR, Newmeyer DD.  The release of cytochrome c from mitochondria: a primary site for Bcl-2 regulation of apoptosis.  Science. 1997 Feb 21;275(5303):1132-6 PMID: 9027315 [PubMed - indexed for MEDLINE]

Click here to view more PubMed publications

Current Laboratory Members

Faculty Member: Ruth Kluck, BSc PhD Qld

Postdoctoral Fellow: Amber Alsop, BSc(Hons) Syd PhD Cantab

Postdoctoral Fellow: Khatira Anwari, BBiomedSc Melb BSc(Hons) Melb PhD Mon

Research Assistant: Stephanie Cherie Coyne, BBiolSc(Hons) LaT

PhD Student: Sweta Iyer BSc Biotech (Bharathiar), MSc Genomics (Madurai Kamaraj)

PhD Student: Colin Hockings, BSc(Hons) Cambridge UK

Honours Student: Vu Tran, BBiomedSc Melb