title: Interdependency of fission yeast Alp14/TOG and coiled coil protein Alp7 in microtubule localization and bipolar spindle formation.
abstract: The Dis1/TOG family plays a pivotal role in microtubule organization. In fission yeast, Alp14 and Dis1 share an essential function in bipolar spindle formation. Here, we characterize Alp7, a novel coiled-coil protein that is required for organization of bipolar spindles. Both Alp7 and Alp14 colocalize to the spindle pole body (SPB) and mitotic spindles. Alp14 localization to these sites is fully dependent upon Alp7. Conversely, in the absence of Alp14, Alp7 localizes to the SPBs, but not mitotic spindles. Alp7 forms a complex with Alp14, where the C-terminal region of Alp14 interacts with the coiled-coil domain of Alp7. Intriguingly, this Alp14 C terminus is necessary and sufficient for mitotic spindle localization. Overproduction of either full-length or coiled-coil region of Alp7 results in abnormal V-shaped spindles and stabilization of interphase microtubules, which is induced independent of Alp14. Alp7 may be a functional homologue of animal TACC. Our results shed light on an interdependent relationship between Alp14/TOG and Alp7. We propose a two-step model that accounts for the recruitment of Alp7 and Alp14 to the SPB and microtubules.
authors.affiliation: Laboratory of Cell Regulation, Cancer Research UK, London Research Institute, Lincoln's Inn Fields Laboratories, London WC2A 3PX, United Kingdom.
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Sato
authors.forename: Leah
authors.initials: L
authors.lastname: Vardy
authors.forename: Miguel
authors.initials: M
authors.lastname: Angel Garcia
authors.forename: Nirada
authors.initials: N
authors.lastname: Koonrugsa
authors.forename: Takashi
authors.initials: T
authors.lastname: Toda
mesh_terms: D001665:Binding Sites; D019084:Fluorescent Antibody Technique, Indirect; D005838:Genotype; D049452:Green Fluorescent Proteins; D007150:Immunohistochemistry; D018386:Kinetochores; D008164:Luminescent Proteins / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000737:chemistry / Q000502:physiology*; D008870:Microtubules / Q000648:ultrastructure*; D008938:Mitosis; D008954:Models, Biological; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012568:Schizosaccharomyces / Q000378:metabolism / Q000502:physiology*; D029702:Schizosaccharomyces pombe Proteins / Q000737:chemistry / Q000502:physiology*; D008941:Spindle Apparatus; D013696:Temperature; D013997:Time Factors; D020798:Two-Hybrid System Techniques
chemical_list: C479626:Alp7 protein, S pombe; D008164:Luminescent Proteins; D008869:Microtubule-Associated Proteins; D029702:Schizosaccharomyces pombe Proteins; C432090:alp14 protein, S pombe; D049452:Green Fluorescent Proteins