Microtubule-dependent motor protein involved in the control of the oriented deposition of cellulose microfibrils (PubMed:20444225; PubMed:21325138). Involved in wall biogenesis and modification; and contributes to cell-cycle progression and cell division (PubMed:20444225). Acts as a transcriptional activator in gibberellic acid (GA) biosynthesis pathway. Binds specifically to the DNA sequence 5'-ACCAACTTGAA-3' of the ent- kaurene oxidase 2 (CYP701A6 or OsKO2) promoter. May regulate CYP701A6 gene expression and mediates cell elongation by regulating the GA biosynthesis pathway (PubMed:21325138). {ECO:0000269|PubMed:20444225; ECO:0000269|PubMed:21325138}.