Is required for spatial control cell division during plant development. Through an association with microtubules, acts both for the positioning of cytoskeletal arrays that establish planes of cell division during prophase and for spatial guidance of expanding phragmoplasts toward preestablished cortical division sites (CDS) during cytokinesis. Interacts with POK1. Preferentially localized to the preprophase band (PPB) during early stage of mitotis and later localized to the cortical division sites (CDS) during cytokinesis. Strongly expressed in flower buds and root tips. No visible phenotype. In cv. Columbia (AC Q84M91), a naturally occurring frameshift at position 444 results in a shortened C-terminus. The sequence shown is from strain cv. Landsberg erecta.