Abstract
The reorganization of microtubules in mitosis, meiosis, and development requires the microtubule-severing activity of katanin. Katanin is a heterodimer composed of an ATPase associated with diverse cellular activities (AAA) subunit and a regulatory subunit. Microtubule severing requires ATP hydrolysis by katanin's conserved AAA ATPase domains. Whereas other AAA ATPases form stable hexamers, we show that katanin forms only a monomer or dimers of heterodimers in solution. Katanin oligomers consistent with hexamers of heterodimers or heterododecamers were only observed for an ATP hydrolysis-deficient mutant in the presence of ATP. X-ray structures of katanin's AAA ATPase in monomeric nucleotide-free and pseudo-oligomeric ADP-bound states revealed conformational changes in the AAA subdomains that explained the structural basis for the instability of the katanin heterododecamer. We propose that the rapid dissociation of katanin AAA oligomers may lead to an autoinhibited state that prevents inappropriate microtubule severing or that cyclical disassembly into heterodimers may critically contribute to the microtubule-severing mechanism.
Keywords:
X-ray crystallography; meiosis; microtubule; microtubule-associated protein (MAP); mitosis; tubulin.
© 2018 by The American Society for Biochemistry and Molecular Biology, Inc.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Adenosine Triphosphatases / chemistry*
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Adenosine Triphosphatases / metabolism
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Animals
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Caenorhabditis elegans / enzymology
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Caenorhabditis elegans Proteins / chemistry*
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Caenorhabditis elegans Proteins / metabolism
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Crystallography, X-Ray
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Humans
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Katanin / chemistry*
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Katanin / metabolism
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Meiosis*
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Microtubules
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Protein Conformation
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Protein Multimerization
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Spindle Apparatus
Substances
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Caenorhabditis elegans Proteins
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Adenosine Triphosphatases
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KATNB1 protein, human
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MEI-1 protein, C elegans
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MEI-2 protein, C elegans
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KATNAL1 protein, human
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Katanin
Associated data
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PDB/5WCB
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PDB/5WC0
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PDB/5UIE
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PDB/4D81
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PDB/4D80
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PDB/3B9P
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PDB/3VFD
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PDB/4L15
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PDB/4L16
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PDB/5WC1
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PDB/5B5D
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PDB/5NBT