Microtubule-associated protein that plays a critical role in organizing the mitotic microtubule array during both early and late mitosis in all plant organs. Essential for the cytokinesis, especially in roots, by maintaining the integrity of the overlapped microtubules in the phragmoplast. Required during root morphogenesis. Needed for giant cell development during root knot nematode infection, where cytokinesis is initiated but not completed. Forms a dimer (By similarity). Binds to microtubules (MT) during cell division. Bundles polymerized MT via the formation of 25-nm crossbridges with centrally located endocytic MT, and midline phragmoplast MT. Locates only to the mitotic MT arrays. Present in MT cortical arrays just before mitosis. Associates to MT in preprophase band, during anaphase, and in phragmoplast, including midzone. Distributed diffusely through the cytoplasm during metaphase only. At the end of cytokinesis, present only at the cell periphery, forming a ring around the newly formed cell plate. During root knot nematode infection, targeted to the giant cell mini cell plate. Expressed in all tissues enriched in dividing cells, such as the root and shoot apical meristem, foliar primordia, and young leaves, and embryos. Present in dividing tissues during all stages of embryonic development. Irregular root expansion. Defects in karyokinesis and cytokinesis. Cytokinesis defects before the embryo dermatogen stage and in roots. Embryos with enlarged nuclei, often containing multiple nucleoli. Some abnormal stomata with pores attached to a single side of the mother cell. Long root hairs. In roots, multinucleated cells, cell wall stubs, and synchronized cell divisions in incompletely separated cells. Normal anaphase spindle, but distorted phragmoplast. Abnormal formation of nematode-mediated giant cells leading to impaired maturation of nematode larvae. Belongs to the MAP65/ASE1 family.