Our research is focused on the biogenesis and operation of chloroplasts and other plastids in plants, particularly in relation to the import of nucleus-encoded proteins and the role of the ubiquitin-proteasome system.
Plastids are a diverse family of plant organelles. The family includes chloroplasts – the organelles responsible for photosynthesis – as well as a range of non-photosynthetic variants such as starch-containing amyloplasts in seeds, tubers and roots, carotenoid-rich chromoplasts in flowers and fruits, and chloroplast-precursor organelles in dark-grown plants called etioplasts. Most plastid proteins are encoded by the nuclear genome and synthesized in the cytosol as precursors with N-terminal targeting signals called transit peptides. Import of precursors into chloroplasts is mediated by the TOC and TIC (Translocon at the Outer/Inner envelope membrane of Chloroplasts) complexes. While much progress has been made in understanding how the import machinery works, substantial gaps remain in our knowledge; for example, the mechanisms underlying the regulation and the evolution of import are poorly understood. Our research seeks to achieve a more complete understanding of chloroplast protein import and of how this vital process is regulated by ubiquitination via a novel pathway called CHLORAD (chloroplast-associated protein degradation). We address these questions using using a full spectrum of molecular, cellular, genetic, biochemical and bioinformatic approaches. We have brought to bear the unique advantages offered by the model plant Arabidopsis thaliana (thale cress) as an experimental system. Nonetheless, having identified potential practical applications of our work we also now employ crop species as alternative models.
Qualifications & Experiences
PhD, >20 years experience supervising graduate students