Arabidopsis Peroxisomes: Biogenesis, Function, and Dynamics
Peroxisomes are single membrane-bound organelles that compartmentalize certain metabolic reactions critical to human and plant development. All proteins functioning in the peroxisome must be synthesized in the cytosol and imported posttranslationally. We are studying peroxisomal processes in the reference plant Arabidopsis thaliana, including the import of matrix proteins from the cytosol into the organelle matrix and the degradation of proteins that become damaged or obsolete after arrival in the peroxisome. Peroxisomal import depends on more than a dozen peroxin proteins that bring proteins bearing peroxisome-targeting sequences into the organelle. We use forward, reverse, and chemical genetic approaches to probe functions of various peroxins, and we are using these tools to elucidate the mechanisms and importance of peroxisome biogenesis and function during plant development.
The student will characterize Arabidopsis peroxin mutants isolated through forward and reverse genetic screens in physiological (measuring growth responses) and biochemical (Western blotting) assays. The interactions between mutant and wild-type peroxin derivatives will be characterized using yeast two-hybrid assays, overexpression studies, and double-mutant analyses.
In humans, deficiencies in peroxins underlie the peroxisomal biogenesis disorders, which are frequently lethal in early infancy. Successful completion of these experiments will advance our understanding of peroxisome biogenesis and metabolism in a genetically distinct model system, enabling the continued refinement of our understanding of these essential organelles.