Microtubule-associated force-producing protein that is targeted to the forming cell plate during cytokinesis. May be involved in attaching Golgi-derived vesicles to microtubules which direct vesicles to the forming cell plate during cytokinesis. Possesses intrinsic GTPase activity in vitro. May homooligomerize and heterooligomerize. May interact with CALS1 and UGT1. Localized in the forming cell plate during cytokinesis (at protein level). Expressed in seedling root tips and root elongation zones, young root nodules and young leaves. The term phragmoplastin refers to the location of the protein to the phragmoplast across the whole width of the newly formed cell plate, unlike phragmoplast microtubules which are concentrated on the periphery of the forming plate. Belongs to the TRAFAC class dynamin-like GTPase superfamily. Dynamin/Fzo/YdjA family.