Regulator of the microtubular cytoskeleton. Microtubule-associated protein involved in the association of cellulase synthase (CESA) complexes (CSCs) and cortical microtubules. Promotes dynamics of CSCs in the plasma membrane. Regulates primary cell wall biosynthesis and cellulose microfibrils organization. Associates with cellulase synthase (CESA) complexes. Binds to cortical microtubules. Colocalizes with cellulase synthase (CESA) complexes (CSCs) in a dynamic way.