Modulating the ubiquitin ligase activity of MDM2
Prof Danny Huang
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APPLY HERE. Application closing date: 9 January 2022.
p53 tumour suppressor protein becomes activated in response to various genotoxic stresses and induces a variety signalling programmess to restore cellular homeostasis. Frequently, p53 is inactivated or mutated in cancers. Cancer cells that express wild type p53 often inactivate p53 by overexpressing ubiquitin ligases such as MDM2 and MDMX to target p53 for ubiquitination and degradation by the proteasome. Disruption of MDM2-p53 interaction by small molecules restores the wild-type p53 activity leading to cell cycle arrest and apoptosis in cancer cells. However, these small molecules often exhibited high on-target toxicity effects.
Recent work from the Huang lab showed that p53 activity could be activated with low toxicity through inactivation of MDM2's ubiquitin ligase activity. We have now identified molecules that bind the catalytic modules of MDM2 and MDMX. This project aims to characterise these molecules by elucidating their binding mechanisms through biophysical and structural analyses and to examine their effects on MDM2 and p53 in cells. The successful candidate will learn and apply techniques including molecular cloning, protein biochemistry, tissue culture assays, and structural characterisation by NMR, X-ray crystallography or Cryo-EM.
Keywords: Ubiquitin, MDM2, p53, biochemistry, structure
Ahmed, S.F., Buetow, L., Gabrielsen, M., Lilla, S., Sibbet, G.J., Sumpton, D., Zanivan, S. Hedley, A., Clark, W. and Huang, D.T. (2021) E3 ligase-inactivation rewires CBL interactome to elicit oncogenesis by hijacking RTK-CBL-CIN85 axis. Oncogene. 40, 2149-2164.
Magnussen, H.M. and Huang, D.T. (2021) Identification of a catalytic active but non-aggregating MDM2 RING domain variant. Journal of Molecular Biology. 433, 166807
Humpton, T.J., Nomura, K., Weber, J., Magnussen, H.M., Hock, A.K., Nixon, C., Dhayade, S., Stevenson, D., Huang, D.T., Strathdee, D., Blyth, K. and Vousden, K.H. (2021) Differential requirements for MDM2 E3 activity during embryogenesis and in adult mice. Genes & Development. 35, 117-132.
Chatrin, C., Gabrielsen, M., Buetow, L., Nakasone, M.A., Ahmed, S.F., Sumpton, D., Sibbet, G.J., Smith, B.O. and Huang, D.T. (2020) Structural insights into ADP-ribosylation of ubiquitin by Deltex family E3 ubiquitin ligases. Science Advances. 6, eabc0418.
Ahmed, S.F., Buetow, L., Gabrielsen, M., Lilla, S., Chatrin, C., Sibbet, G.J., Zanivan, S. and Huang, D.T. (2020) DELTEX2 C-terminal domain recognizes and recruits ADP-ribosylated proteins for ubiquitination. Science Advances 6, eabc0629.
For informal enquiries or further details on the project, please email Prof Danny Huang (email@example.com).