Abstract: Our appreciation of the complexity and evolution of taxonomically diverse eukaryotic cells is highly constrained by our limited knowledge of the locations and functions of most of the cell’s proteome. Typically, few, if any, proteins have been located in a given taxon, and even the better studied eukaryotes, such as some human pathogens, have only a very small fraction of proteins’ locations experimentally determined. At best, many protein locations are predicted based on studies of homologues from distant relatives. But, more often, proteins predicted from genomes or transcriptomes are ‘hypotheticals’ unique to a taxon’s lineage, stymying even predictions of location or function by comparative biology. To address this deficit in our basic understanding of the compositional organisation of the cell, we have used a spatial proteomics method called hyperLOPIT to simultaneously capture the steady-state subcellular association of thousands of proteins in the apicomplexan Toxoplasma. We have resolved almost 4000 proteins to locations including endosymbiotic organelles, secretory compartments related to invasion, discrete cytoskeletal structures, sub-nuclear compartments and large molecular complexes. These protein atlases reveal: protein associations throughout the cell providing testable hypotheses of their function; coordinated transcriptional control of discrete cell compartments; conservation and novelty of compartment proteomes both between apicomplexans, and other eukaryotes; different paces of evolution across the different cell compartments and structures in Toxoplasma; and clear instances of protein relocation from one organelle or structure to a different one over evolutionary time. This new, global view of the cell proteome provides a much more complete framework for understanding the mechanisms of function and evolution of these cells.

Biography: Bio-Sketch: Ross Waller completed a PhD in 2000 in Melbourne, Australia (School of Botany, University of Melbourne) working on the newly discovered remnant plastid in apicomplexan parasites Plasmodium and Toxoplasma with Geoffrey McFadden. He undertook postdoctoral training from 2000-3 as a Peter Doherty Fellow with Malcolm McConville working on Leishmania cell biology (Department of Biochemistry, University of Melbourne), and then from 2003-5 as a Canadian Institutes of Health Research and Michael Smith Foundation for Health Research Fellow with Patrick Keeling working on molecular evolution in diverse eukaryotes (University of British Columbia, Canada). In 2005 be joined the faculty of the School of Botany, University of Melbourne, and in 2013 relocated his laboratory to the Department of Biochemistry, University of Cambridge.

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