6b5d
From Proteopedia
Structural Basis for Katanin Self-Assembly
Structural highlights
Function[KTNA1_CAEEL] Catalytic subunit of a complex which severs microtubules in an ATP-dependent manner. Microtubule severing may promote rapid reorganization of cellular microtubule arrays. Required specifically for meiotic spindle formation in the female germline; the presence of this protein is inimical to the formation of mitotic spindles (PubMed:8027178, PubMed:10809666, PubMed:12885567). In body wall muscles, regulates organization of myosin thick filaments (PubMed:22621901).[HAMAP-Rule:MF_03023][1] [2] [3] [4] Publication Abstract from PubMedThe 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 only forms 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 reveal conformational changes in AAA subdomains that explained the structural basis for instability of katanin heterododecamer. We propose that the rapid dissociation of katanin AAA oligomers may lead to an auto-inhibited state that prevents inappropriate microtubule severing, or that cyclical disassembly into heterodimers may critically contribute to the microtubule-severing mechanism. Structural Basis for Disassembly of Katanin Heterododecamers.,Nithianantham S, McNally FJ, Al-Bassam J J Biol Chem. 2018 May 11. pii: RA117.001215. doi: 10.1074/jbc.RA117.001215. PMID:29752405[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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