Microtubule disassembly by ATP-dependent oligomerization of the AAA enzymekatanin

Katanin, a member of the AAA adenosine triphosphatase (ATPase) superfamily, uses nucleotide hydrolysis energy to sever and disassemble microtubules. M any AAA enzymes disassemble stable protein-protein complexes, but their mec hanisms are not well understood. A fluorescence resonance energy transfer a ssay demonstrated that the p60 subunit of katanin oligomerized in an adenos ine triphosphate (ATP)- and microtubule-dependent manner. Oligomerization i ncreased the affinity of katanin for microtubules and stimulated its ATPase activity. After hydrolysis of ATP, microtubule-bound katanin oligomers dis assembled microtubules and then dissociated into free katanin monomers. Cou pling a nucleotide-dependent oligomerization cycle to the disassembly of a target protein complex may be a general feature of ATP-hydrolyzing AAA doma ins.