Research

Mark Wilkinson

The mechanics of the eukaryotic actin protein-folding machinery from yeast to malaria

Mark Wilkinson - 2nd year PhD

Abstract

Conventional wisdom sees the journey of a protein from DNA transcription, through translation to the finished protein product. However, for many essential proteins within a cell, a myriad of factors assist in checking and correcting the folding of proteins after their translation to ensure each are functional. This is particularly true for the protein actin, one of the critical components that defines the ability of a cell to move, grow and divide. Actin has its own dedicated folding machinery, a beautiful, spherically-shaped megadalton structure called the chaperonin containing TCP1 complex (CCT), which folds newly formed actin polypeptides in an ATP-dependent manner. Whilst structural information and understanding of the ATP-dependent folding cycle is available for yeast and mammalian CCT complexes, to date we know little about either the biophysics of the CCT folding process or the forces involved in shaping native proteins. In addition, nothing is known about more divergent CCT complexes, such as that from the evolutionarily ancient protozoan Plasmodium, the causative agent of human malaria. Given this pathogen’s reliance on actin, understanding into its chaperonin system could underpin future development of drugs to combat the cause of over half a million deaths each year, predominantly in children under the age of 5 in the developing world.

This ambitious studentship will develop combined physical and biochemical approaches to characterize CCT-actin interactions in real time, extending and developing understanding of yeast and mammalian systems to the malaria parasite CCT complex and its unique interaction with parasite actin. The project will make unique contributions to our understanding of actin folding and explore the potential for probe-based targeting of the CCT machinery for chemical tool and antimalarial drug discovery.

The project builds on extensive work on the CCT complex by the laboratory of Prof. Keith Willison in the Department of Chemistry at ICL and its recent extension into malaria parasite cell biology with Dr. Jake Baum, from Life Sciences. The project will utilize advanced techniques in parasite transgenics, structural investigation using single particle cryoEM, and single molecule analysis of protein folding using state-of-the-art atomic force microscopy developed in the laboratory of Dr. Armando Del Rio Hernandez from the ICL Department of Engineering.