Open AccessKatanin spiral and ring structures shed light on power stroke for microtubule severing
Author(s) -
Elena A. Zehr,
Agnieszka Szyk,
Grzegorz Piszczek,
Ewa Szczęsna,
Xiaobing Zuo,
Antonina Roll-Mecak
Publication year - 2017
Publication title -
nature structural and molecular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 9.448
H-Index - 270
eISSN - 1545-9993
pISSN - 1545-9985
DOI - 10.1038/nsmb.3448
Subject(s) - microtubule , random hexamer , aaa proteins , microbiology and biotechnology , microtubule nucleation , biogenesis , biophysics , chemistry , atpase , biology , enzyme , crystallography , biochemistry , centrosome , cell , cell cycle , gene
Microtubule-severing enzymes katanin, spastin and fidgetin are AAA ATPases important for the biogenesis and maintenance of complex microtubule arrays in axons, spindles and cilia. Because of a lack of known 3D structures for these enzymes, their mechanism of action has remained poorly understood. Here we report the X-ray crystal structure of the monomeric AAA katanin module from Caenorhabditis elegans and cryo-EM reconstructions of the hexamer in two conformations. The structures reveal an unexpected asymmetric arrangement of the AAA domains mediated by structural elements unique to microtubule-severing enzymes and critical for their function. The reconstructions show that katanin cycles between open spiral and closed ring conformations, depending on the ATP occupancy of a gating protomer that tenses or relaxes interprotomer interfaces. Cycling of the hexamer between these conformations would provide the power stroke for microtubule severing.