Plant cells are surrounded by rigid walls that immobilize the cells within a tissue, thus the orientation in which
plant cells divide during development determines organ shape and is critical for establishing the cellular
organization of plant tissue. Cell division is accomplished by the coordinated distribution of nuclear and
cytoplasmic information to daughter cells. The partitioning of daughter nuclei and other cell components into
separate cells after mitosis is known as cytokinesis. The cytoskeleton is a key player in cell division and
morphogenesis. In plant cells, four cytoskeletal arrays are present during the cell cycle. The orientation of the new
cell wall is determined by the cytoskeleton prior to the onset of mitosis. Cytokinesis is achieved by the
phragmoplast, which is a microtubule cytoskeletal array that is guided to the site of cell division and helps to
establish the new cell wall. Microtubule associated proteins (MAPs), like the motor proteins kinesins are important
components of these assemblies. Chromosome separation and the establishment of the new cell wall are achieved
by the vigorous redistribution of cytoskeleton elements, which is thought to be achieved in part by the orchestrated
action of microtubule motor proteins, which include a remarkable variety of kinesins. Only a few of these proteins
have been characterized in plants. To learn more about the role of kinesins in cytokinesis, I am characterizing two
kinesins, KAT1 and KAT2, which are likely to interact with the protein ATN in Arabidopsis. The ATN gene is the
Arabidopsis ortholog of the maize TANGELD1 gene, that helps orient the cytoskeletal arrays during cell cycle.