title: Microtubule severing by katanin p60 AAA+ ATPase requires the C-terminal acidic tails of both α- and β-tubulins and basic amino acid residues in the AAA+ ring pore.
abstract: The microtubule (MT) network is highly dynamic and undergoes dramatic reorganizations during the cell cycle. Dimers of α- and β-tubulins rapidly polymerize to and depolymerize from the end of MT fibrils in an intrinsic GTP-dependent manner. MT severing by ATP-driven enzymes such as katanin and spastin contributes significantly to microtubule dynamics, and it has been shown that katanin p60, a AAA+ family protein, has ATPase and MT-severing activities. The mechanism of MT severing by katanin p60 is poorly understood, and the residues in katanin p60 and tubulins important for severing activity were therefore explored in this study. MT-severing activity, but not ATPase activity, was inhibited by mutations of the conserved aromatic residue and the flanking basic residues in the pore region of the katanin p60 hexameric ring. When the acidic residue-rich C-terminal unstructured segment of either α- or β-tubulin was removed, polymerized MTs were resistant to katanin p60 treatment. Interactions between katanin p60 and the mutant MTs, on the other hand, were unaffected. Taken together, these findings led us to propose that the interactions between the positively charged residues of katanin p60 and the acidic tails of both tubulins are essential for efficient severing of MTs.
authors: From the Department of Molecular Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811.
authors: Ai
authors: A
authors: Johjima
authors: From the Department of Molecular Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, the Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Tokyo 102-0076, and the Graduate School of Engineering Science, Osaka University, Osaka 560-8531, Japan.
authors: Kentaro
authors: K
authors: Noi
authors: From the Department of Molecular Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811.
authors: Shingo
authors: S
authors: Nishikori
authors: the Graduate School of Engineering Science, Osaka University, Osaka 560-8531, Japan.
authors: Hirotsugu
authors: H
authors: Ogi
authors: From the Department of Molecular Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, the Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Tokyo 102-0076, and esaki@kumamoto-u.ac.jp.
authors: Masatoshi
authors: M
authors: Esaki
authors: From the Department of Molecular Cell Biology, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto 860-0811, the Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Tokyo 102-0076, and ogura@gpo.kumamoto-u.ac.jp.
authors: Teru
authors: T
authors: Ogura
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000378:metabolism*; D000595:Amino Acid Sequence; D024361:Amino Acids, Basic; D000818:Animals; D017124:Conserved Sequence; D006801:Humans; D000074201:Katanin; D008870:Microtubules / Q000378:metabolism*; D008969:Molecular Sequence Data; D016062:Porosity; D012617:Sea Urchins; D061987:Sf9 Cells; D018411:Spodoptera; D014404:Tubulin / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D024361:Amino Acids, Basic; D014404:Tubulin; D000251:Adenosine Triphosphatases; D000074201:Katanin
keywords: ATPases Associated with Diverse Cellular Activities (AAA); Katanin; Microtubule; Sea Urchin; Tubulin; Yeast