May participate in a complex which severs microtubules in an ATP-dependent manner (By similarity). This activity may promote rapid reorganization of cellular microtubule arrays (By similarity). Confers precision to microtubule (MT) severing by specific targeting of KTN1 to MT cleavage sites such as crossover or branching nucleation sites (PubMed:28978669). Together with other KTN80s, regulates cell elongation by modulating MT organization (PubMed:28978669). Component of KTN80-KTN1 complexes composed of a hexamer of KTN1-KTN80 heterodimers that sense microtubule (MT) geometry to confer precise MT severing (PubMed:28978669). Interacts directly with AAA1/KTN1, and weakly with KTN80.1 and KTN80.3 (PubMed:28978669). Present in dynamic discrete particles specifically localized to microtubule (MT) crossovers and branching nucleation sites. Expressed in siliques, flowers, leaves, stems and roots. The DWD box is required for interaction with DDB1A. The double mutant ktn80.3 ktn80.4 exhibits normal growth, but the quadruple mutant ktn80.1 ktn80.2 ktn80.3 ktn80.4 has a severe dwarf phenotype, with small and round dark-green rosette leaves as well as wide and short petioles, probably due to cell elongation defects, and associated with a complex cortical microtubule (MT) network with stable entanglements (PubMed:28978669). Plants missing KTN80s have a disruption of KTN1 recruitment at MT crossover or branching nucleation sites, leading to an abolishment of MT severing (PubMed:28978669). May be due to a competing acceptor splice site. Belongs to the WD repeat KATNB1 family.