Department of Molecular, Cellular and Developmental Biology - University of Michigan-Ann Arbor

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Host:  Olga Zabotina

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"Analysis of the Roles of CSLD Proteins During Polarized Plant Cell Wall Deposition in Arabidopsis"

Plant cell expansion is governed by the deposition of new cell wall components, and cellulose microfibrils, the major load bearing components in plant cell walls, are deposited along one or more entire faces of a cell during diffuse growth.  However, during tip growth, newly synthesized cell wall polysaccharides are deposited in a restricted region.

Previously we have shown that the cellulose synthase-like D family protein, CSLD3, localizes to the tips of growing root hairs and provides essential cell wall synthase activity during root hair tip growth.  We have further demonstrated that fluorescently-tagged CSLD2/3/5 proteins localize to newly-forming cell plates in dividing cells, providing essential cell wall synthase activities for the de novo formation of these new cell walls during plant cell cytokinesis. We have also shown that CSLD5 is an unstable protein that is degraded in a cell-cycle dependent manner.

We will also present recent results clarifying the identity of the polysaccharides synthesized by CSLD proteins using a combination of genetic rescue experiments with CSLD-CESA chimeric proteins, and in vitro biochemical reconstitution experiments with CSLD, CSLA, and CESA proteins expressed and purified from S. cerevisiae microsomal membranes.