Principle Investigator
Lab members
Projects
Publications
Photogallery
Purdue Motility Group
Biological Sciences
Bio
Professor& University Faculty Scholar
Ph.D., 1990 Univ. of California, Berkley
Ph. (765) 496-1769
Bio Sketch (.pdf format)
The ultimate goal of our research is to understand how a network of filamentous structures, the cytoskeleton, functions during plant growth and response to biotic and abiotic stimuli. Cytoskeletal polymers called actin filaments power diverse cellular motility events. Although plant cells are not motile, actin filaments contribute to the dynamic intracellular movement of organelles and vesicles, coordinate endo- and exocytosis, and organize the cellular architecture. In addition to mechanochemical enzymes or motor proteins, including the myosins that hydrolyze ATP to run along cytoskeletal tracks, the energy of actin polymerization itself can be harnessed to perform work. Actin dynamics, or the rapid turnover of actin filaments, play a central role in these cellular processes. A large and diverse cast of characters, accessory proteins known as actin-binding proteins, modulate actin dynamics through binding to the monomer pool, interacting with the side and ends of filaments, creating breaks along a filament, and generating new filaments de novo. We use a combination of biochemistry, cell biology and advanced imaging technologies, as well as reverse-genetics to understand the properties and function of plant actin-binding proteins. Recent biochemical and single filament imaging analyses of several conserved classes of plant actin-binding proteins reveal unusual and unexpected properties. Notable examples include: an abundant monomer-binding protein (CAP) that catalyzes nucleotide exchange; a barbed-end capping protein (CP) that is dissociated from filament ends by the signaling lipid, phosphatidic acid; a villin-like bundling protein (VLN1) that lacks all Ca2+-regulated activities; and a formin family member (AFH1) that is non-processive and is sufficient to generate actin filament bundles. These and other recent discoveries motivate a careful description of the properties of plant proteins in vitro as a prelude to greater insight about the molecular mechanism(s) underlying the regulation of actin dynamics in vivo.