Targeting the ubiquitin system function through GID4 - Year two
Protein turnover is an incompletely understood aspect of biology, important for various processes including adaption to environmental stimuli. Over 500 protein complexes (E3 ligases) are involved in marking proteins for degradation, but only a small number of these E3 ligases are well characterised. The current project seeks to develop chemical inhibitors of GID4—a key component of an E3 ligase complex called C-terminal to LisH (CTLH). This E3 ligase is thought to play a role in nutrient sensing and autophagy, which are both implicated in chemotherapy resistance of cancer cells. Yeast Gid4 is known to recognise and degrade substrates containing an N-terminal proline (Pro/N-end rule), but mammalian GID4 appears to have lost specificity for this recognition motif. I propose to test binding of inhibitors to GID4 in cells using a variety of techniques to establish compound activity and selectivity. Next, inhibitors will be used to investigate the role of CTLH in autophagy. Finally, proteins whose turnover is regulated by CTLH will be investigated. The development of Inhibitors against CTLH in this project will reveal insights into the biology of this poorly understood but therapeutically promising E3 ligase and may provide therapeutic opportunities in various disease settings such as cancer.