Richard Marshall

Ph.D. in Molecular Cell Biology, University of Warwick (UK), 2008

BSc in Biochemistry, University of Warwick (UK), 2004


My work focuses on a genetic and biochemical analysis of the 26S proteasome, a large multi-subunit complex that functions as the major protein degradation machinery in plants and other eukaryotes. The 26S proteasome is composed of two functionally distinct subcomplexes, namely the 20S core protease and the 19S regulatory particle. The regulatory particle docks to one or both ends of the core protease and imparts ATP-dependence and substrate specificity, in particular with regards to proteins modified with ubiquitin polymers. The regulatory particle consists of base and lid subcomplexes. The base contains a hexameric ring of AAA-ATPases designated RPT1 to RPT6 and three non-ATPase subunits, RPN1, RPN2 and RPN10, while the lid is composed of RPN3, 5, 6, 7, 8, 9, 10, 11, 12, 13 and 15, plus an assortment of accessory proteins present at substoichiometric levels. My aim is to further characterise the role of various subunits of the 19S regulatory particle, including RPN3, RPT4 and RPN11 in the model plant Arabidopsis thaliana. Additionally, previous work has indicated that the RPN1a and RPN2 subunits are themselves ubiquitinated in Arabidopsis, and we aim to elucidate the significance of this post-translational modification to the overall of fate of the proteasome complex.