BIOL 537 2012-13
Dr. K. Ko

Plastids occupy a central role in a range of biosynthetic activities such as photosynthesis, amino acid synthesis, and oil production.  These activities rely on the plastid's ability to adjust during development and to the ever-changing environment of a plant cell.  The pressure to adjust can come from both internal and external sources.  Such adjustments are generally accompanied by dramatic changes to the diversity of proteins being transported.  It is thus important for plastids to maintain a responsive and efficient protein transport process that can address all situations.

Recent findings from our lab indicate that the co-chaperone Tic40, a dynamic component of the plastid protein transport machinery, may be involved in the adjusting mechanisms and that Tic40's role(s) may be influenced or modulated by the activities of a newly-discovered class of organellar rhomboid proteases.  Our current research effort is aimed at elucidating the relationship between Tic40 and organellar rhomboid proteases.  Since these rhomboid proteases belong to a group of highly conserved proteins involved in signaling and development in other systems like Drosophila, our long-term goal will be to investigate the relationship between rhomboid proteases, plastid protein delivery, organelle biogenesis, cell structure, signalling, and development in Arabidopsis. 

A combination of established and modern proteomic approaches will be employed in the short-term to specifically:

1) elucidate the structural features involved in the Tic40-plastid rhomboid protease interaction;
2) characterize the newly-discovered organellar processing proteases, such as expression, post-transcriptional processing, location, targeting, and enzymatic activities.

Research areas in which specific Biol537 projects may reside

Area #1 Characterize

Arabidopsis plants with loss-of-function mutations in organellar rhomboid proteases

Area #2 Characterize

transgenic Arabidopsisplants with altered levels of rhomboid protease substrates

Area #3 Expression profiling of the

rhomboid protease genes and their substrates

Area#4 Elucidate alternative splicing patterns for the

rhomboid protease genes and their substrates