Severs microtubules in vitro in an ATP-dependent manner. This activity may promote rapid reorganization of cellular microtubule arrays. n ATP + n H2O + a microtubule = n ADP + n phosphate + (n+1) alpha/beta tubulin heterodimers. Localizes within the cytoplasm, partially overlapping with microtubules in interphase and to the mitotic spindle and spindle poles during mitosis. Belongs to the AAA ATPase family. Katanin p60 subunit A1 subfamily. A-like 2 sub-subfamily.