Biology

Dr. Anindya Ganguly
Center for Membrane and Cell Physiology Molecular Physiology and Biological Physics University of Virginia, Charlottesville, VA

Abstract:

Construction of the plant cell wall demands harmonized deposition of cellulose and matrix polysaccharides. Cortical microtubules orient the deposition of cellulose by guiding the trajectory of plasma membrane-embedded cellulose synthase complexes. My research shows that vesicles containing matrix polysaccharides are transported by the FRAGILE FIBER 1 kinesin (FRA1 or kinesin-4a) to facilitate their secretion along the cortical microtubules. The cortical microtubule cytoskeleton thus provides a platform to coordinate the delivery of cellulose and matrix polysaccharides. Moreover, the FRA1 kinesin physically interacts with CELLULOSE SYNTHASE-MICROTUBULE UNCOUPLING proteins (CMU) proteins which regulates the lateral stability of cortical microtubules and are important for the microtubule-dependent guidance of cellulose synthase complexes. Interestingly, the plant cell wall growth is developmentally regulated and so is FRA1 activity. Plants regulate the abundance of FRA1 motors by the proteasome-pathway, so that high FRA1 activity in growing cells ensures high rate of secretion of cell wall materials required for rapid cellular expansion. Altogether, my research shows how a kinesin motor along with an intricate network of its interaction partners delicately controls the magnitude of cargo transport during cell wall expansion.