The role of phosphorylation in the regulation of pro-apoptoic Bax
Project type
Honours
| Supervisor(s) | Division | |
| (Primary) | Cell Signalling and Cell Death | .(JavaScript must be enabled to view this email address) |
| (Co-supervisor) | Molecular Genetics of Cancer | .(JavaScript must be enabled to view this email address) |
Robert Ninnis (Co-supervisor) |
Cell Signalling and Cell Death | .(JavaScript must be enabled to view this email address) |
Details of project
Apoptotic cell death is essential for normal development and a proper functioning immune system. Disrupted regulation of apoptosis is a major contributor to tumorigenesis and renders many tumours resistant to standard chemotherapies. Therefore understanding how apoptosis is controlled is paramount for the effective treatment of cancer.
The main pathway to cell death is regulated by the Bcl-2 family of proteins. Members of this family, Bax and Bak, are critical mediators of apoptosis and their activity is necessary for a cell to die in response to apoptotic stresses (1,2). However, despite their clear importance, how Bax or Bak convert from their dormant state to an activated one during apoptosis is unknown (3). Reports have implicated a role for post-translational modifications, including phosphorylation, in Bax and Bak, however the relevance of these potential modifications to apoptotic function is unclear (4-6).
This project investigates the role of phosphorylation in regulating the pro-apoptotic function of Bax. The project will utilise several complementary cell and molecular biology approaches including PCR mutagenesis, electrophoresis (SDS-PAGE, isoelectric focussing, blue native PAGE), and mass spectrometry to address the following aims:
- To determine whether Bax is phosphorylated either in healthy cells or apoptotic cells.
- To test the role of putative phosphorylation sites in Bax apoptotic function.
This project will address an important issue in the field and enable a more rational approach to targeting apoptosis and Bax function therapeutically.
Project references
- Dewson G and Kluck RM. Mechanisms of mitochondrial outer membrane permeabilisation in apoptosis. J Cell Science. 2009 Aug 15;122(16):2801-2808. PMID: 19795525
- Wei MC, Zong WX, Cheng EH, Lindsten T, Panoutsakopoulou V, Ross AJ, Roth KA, MacGregor GR, Thompson CB, Korsmeyer SJ. Proapoptotic BAX and BAK: a requisite gateway to mitochondrial dysfunction and death. Science. 2001 Apr 27;292(5517):727-30. PMID:11326099
- Westphal D, Dewson G, Czabotar PE, Kluck RM. Molecular biology of Bax and Bak activation and action. Biochim Biophys Acta. 2010 Dec 30. PMID: 21195116
- Fox JL, Ismail F, Azad A, Ternette N, Leverrier S, Edelmann MJ, Kessler BM, Leigh IM, Jackson S, Storey A. Tyrosine dephosphorylation is required for Bak activation in apoptosis. EMBO J. 2010 Nov 17;29(22):3853-68. PMID:20959805
- Wang Q, Sun SY, Khuri F, Curran WJ, Deng X. Mono- or double-site phosphorylation distinctly regulates the proapoptotic function of Bax. PLoS One. 2010 Oct 14;5(10):e13393.PMID:20976235
- Gardai SJ, Hildeman DA, Frankel SK, Whitlock BB, Frasch SC, Borregaard N, Marrack P, Bratton DL, Henson PM. Phosphorylation of Bax Ser184 by Akt regulates its activity and apoptosis in neutrophils. J Biol Chem. 2004 May 14;279(20):21085-95. PMID:14766748
Research interests
The focus of our laboratory is the process by which cells die by apoptosis. Apoptotic cell death is essential for normal development and a functioning immune system but without appropriate control, diseases including cancer and neurodegenerative disorders can develop.
Critical regulators of apoptosis are the Bcl-2 proteins. Two of these, Bak and Bax, kill cells by damaging the powerhouses of the cell, the mitochondria, but how they do so is unclear. Furthermore, how their deadly activity is restrained in healthy cells and unleashed following a death stimulus is controversial. We have made some key findings relating to how Bak and Bax are regulated and how they function to kill cells (Dewson et al, Mol Cell 2008; Dewson et al, Mol Cell 2009).
Our work aims to clarify these important issues using classical and innovative cell biology and biochemical approaches. The long-term aim of our research is to exploit this knowledge to develop new tools to interrogate Bak and Bax function in disease and identify novel ways by which apoptosis can be therapeutically manipulated. Such therapies represent potentially valuable treatments of diseases including cancer, neurodegenerative disorders such as Parkinson’s disease and certain autoimmune conditions.
Selected publications
- Westphal D, Dewson G, Czabotar PE, Kluck RM. Molecular biology of Bax and Bak activation and action. Biochim Biophys Acta. 2010 Dec 30. Epub ahead of print. PMID: 21195116
- Dewson G, Kratina T, Czabotar P, Day CL, Adams JM, Kluck RM. Bak activation for apoptosis involves oligomerization of dimers via their α6 helices. Mol Cell. 2009 Nov 25;36(4):696-703. PMID: 19941828
- Dewson G and Kluck RM. Mechanisms of mitochondrial outer membrane permeabilisation in apoptosis. J Cell Science. 2009 Aug 15;122(16):2801-2808. PMID: 19795525
- Dewson G, Kratina T, Sim HW, Puthalakath H, Colman PM and Kluck RM. To trigger apoptosis Bak exposes its BH3 domain and homo-dimerizes via BH3:groove interactions. Mol Cell. 2008 May 9;30(3):369-380. PMID: 18471982
Research theme
Cancer
Scientific discipline
- Biochemistry
- Cell Biology
- Molecular Biology
Keywords
Apoptosis, Bax, phosphorylation, cancer, mitochondria