title: The far C-terminus of MCAK regulates its conformation and spindle pole focusing.
abstract: To ensure proper spindle assembly, microtubule (MT) dynamics needs to be spatially regulated within the cell. The kinesin-13 MCAK is a potent MT depolymerase with a complex subcellular localization, yet how MCAK spatial regulation contributes to spindle assembly is not understood. Here we show that the far C-terminus of MCAK plays a critical role in regulating MCAK conformation, subspindle localization, and spindle assembly in Xenopus egg extracts. Alteration of MCAK conformation by the point mutation E715A/E716A in the far C-terminus increased MCAK targeting to the poles and reduced MT lifetimes, which induced spindles with unfocused poles. These effects were phenocopied by the Aurora A phosphomimetic mutation, S719E. Furthermore, addition of the kinesin-14 XCTK2 to spindle assembly reactions rescued the unfocused-pole phenotype. Collectively our work shows how the regional targeting of MCAK regulates MT dynamics, highlighting the idea that multiple phosphorylation pathways of MCAK cooperate to spatially control MT dynamics to maintain spindle architecture.
authors.affiliation: Department of Biology, Indiana University, Bloomington, IN 47405.
authors.forename: Hailing
authors.initials: H
authors.lastname: Zong
authors.affiliation: Department of Biology, Indiana University, Bloomington, IN 47405.
authors.forename: Stephanie K
authors.initials: SK
authors.lastname: Carnes
authors.affiliation: Department of Biology, Indiana University, Bloomington, IN 47405.
authors.forename: Christina
authors.initials: C
authors.lastname: Moe
authors.affiliation: Medical Sciences Program, Indiana University, Bloomington, IN 47405 scems@indiana.edu cwalczak@indiana.edu.
authors.forename: Claire E
authors.initials: CE
authors.lastname: Walczak
authors.affiliation: Medical Sciences Program, Indiana University, Bloomington, IN 47405 scems@indiana.edu cwalczak@indiana.edu.
authors.forename: Stephanie C
authors.initials: SC
authors.lastname: Ems-McClung
mesh_terms: D000818:Animals; D064096:Aurora Kinase A / Q000378:metabolism; D002453:Cell Cycle; D016547:Kinesins / Q000235:genetics* / Q000378:metabolism* / Q000502:physiology; D008870:Microtubules / Q000378:metabolism / Q000502:physiology; D008968:Molecular Conformation; D010766:Phosphorylation; D000072417:Protein Domains; D017434:Protein Structure, Tertiary; D008941:Spindle Apparatus / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D064047:Spindle Poles / Q000378:metabolism; D029867:Xenopus Proteins / Q000235:genetics* / Q000378:metabolism* / Q000502:physiology; D014982:Xenopus laevis / Q000378:metabolism
chemical_list: D029867:Xenopus Proteins; C509242:mitotic centromere-associated kinesin, Xenopus; D064096:Aurora Kinase A; D016547:Kinesins