title: Separase Promotes Microtubule Polymerization by Activating CENP-E-Related Kinesin Kin7.
abstract: Microtubules play an essential role in breaking cellular symmetry. We have previously shown that separase associates with microtubules and regulates microtubule-dependent establishment of cell polarity in Arabidopsis. However, separase lacks microtubule-binding activity, raising questions about mechanisms underlying this phenomenon. Here we report that the N-terminal non-catalytic domain of separase binds to the C-terminal tail domain of three homologs of the centromeric protein CENP-E Kinesin 7 (Kin7). Conformational changes of Kin7 induced upon binding to separase facilitate recruitment of Kin7/separase complex (KISC) onto microtubules. KISC operates independently of proteolytic activity of separase in promoting microtubule rescue and pauses, as well as in suppressing catastrophes. Genetic complementation experiments in conditional separase mutant rsw4 background demonstrate the importance of KISC for the establishment of cell polarity and for plant development. Our study establishes a mechanism governing microtubule dynamics via the separase-dependent activation of CENP-E-related kinesins.
authors.affiliation: Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, PO Box 7080, 75007 Uppsala, Sweden. Electronic address: panagiotis.moschou@slu.se.
authors.forename: Panagiotis N
authors.initials: PN
authors.lastname: Moschou
authors.affiliation: Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, PO Box 7080, 75007 Uppsala, Sweden; Department of Chemistry and Biotechnology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, PO Box 7015, 75007 Uppsala, Sweden.
authors.forename: Emilio
authors.initials: E
authors.lastname: Gutierrez-Beltran
authors.affiliation: Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, PO Box 7080, 75007 Uppsala, Sweden; Department of Chemistry and Biotechnology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, PO Box 7015, 75007 Uppsala, Sweden.
authors.forename: Peter V
authors.initials: PV
authors.lastname: Bozhkov
authors.affiliation: Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA; Institute for Global Food Security, Queen's University Belfast, 18-30 Malone Road, Belfast BT9 5BN, UK. Electronic address: andrei.smertenko@wsu.edu.
authors.forename: Andrei
authors.initials: A
authors.lastname: Smertenko
mesh_terms: D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000378:metabolism*; D055162:Biocatalysis; D048750:Cell Nucleus Division; D016764:Cell Polarity; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D004798:Enzymes / Q000378:metabolism*; D018522:Gravitropism; D016547:Kinesins / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism*; D009024:Morphogenesis; D046912:Multiprotein Complexes / Q000378:metabolism; D058105:Polymerization; D011485:Protein Binding; D000072417:Protein Domains; D059748:Proteolysis; D064247:Separase / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013696:Temperature
chemical_list: D029681:Arabidopsis Proteins; D002868:Chromosomal Proteins, Non-Histone; D004798:Enzymes; D046912:Multiprotein Complexes; C068688:centromere protein E; C450151:epithiospecifier protein, Arabidopsis; D064247:Separase; D016547:Kinesins