Regulating Protein Lifetime in Plants
Cells and the organelles within them have multiple systems to break proteins and peptides into their constituent amino acids. Protein degradation, known as proteolysis, is critical to the life cycle of healthy cells, allowing for the removal of unwanted or damaged proteins and regulation of metabolism and other cellular processes. In plants, the proteolytic systems of chloroplasts—the chlorophyll-rich organelles responsible for photosynthesis—are of particular interest, since chloroplasts are functionally linked to the production of compounds with nutritional and pharmaceutical value. Yet, the proteolytic systems at work in chloroplasts are poorly understood.
Klaas Van Wijk, School of Integrative Plant Science, Plant Biology, is providing insights into the network of enzymes responsible for proteolysis in chloroplasts. The project will focus on the central chloroplast Clp protease system, with the goal of unraveling the functional, structural, and mechanistic details of a novel adaptor system with two components: ClpS1 and ClpF. Using Arabidopsis (rockcress) protease mutants and previously identified candidate Clp substrate and Clp adaptors, Van Wijk is illuminating the biomolecular processes that determine substrate selection, substrate half-life, and Clp protein chaperone interactions that are crucial to the Clp protease system.
The research will provide fundamental insights into determinants of chloroplast protein lifetime and degradation. The results could enable more rational protein design for the stable accumulation of chloroplast proteins. The results may also contribute to new technologies for tuning protein degradation. Both outcomes have important applications in molecular farming and synthetic biology, with implications for pharmaceutical development, nutrition, and human health.