title: Csi1p recruits alp7p/TACC to the spindle pole bodies for bipolar spindle formation.
abstract: Accurate chromosome segregation requires timely bipolar spindle formation during mitosis. The transforming acidic coiled-coil (TACC) family proteins and the ch-TOG family proteins are key players in bipolar spindle formation. They form a complex to stabilize spindle microtubules, mainly dependent on their localization to the centrosome (the spindle pole body [SPB] in yeast). The molecular mechanism underlying the targeting of the TACC-ch-TOG complex to the centrosome remains unclear. Here we show that the fission yeast Schizosaccharomyces pombe TACC orthologue alp7p is recruited to the SPB by csi1p. The csi1p-interacting region lies within the conserved TACC domain of alp7p, and the carboxyl-terminal domain of csi1p is responsible for interacting with alp7p. Compromised interaction between csi1p and alp7p impairs the localization of alp7p to the SPB during mitosis, thus delaying bipolar spindle formation and leading to anaphase B lagging chromosomes. Hence our study establishes that csi1p serves as a linking molecule tethering spindle-stabilizing factors to the SPB for promoting bipolar spindle assembly.
authors: Department of Biochemistry, University of Hong Kong, Pokfulam, Hong Kong, China HKU-Shenzhen Institute of Research and Innovation, University of Hong Kong, Shenzhen, China.
authors: Fan
authors: F
authors: Zheng
authors: Department of Biochemistry, University of Hong Kong, Pokfulam, Hong Kong, China HKU-Shenzhen Institute of Research and Innovation, University of Hong Kong, Shenzhen, China.
authors: Tianpeng
authors: T
authors: Li
authors: Department of Biochemistry, University of Hong Kong, Pokfulam, Hong Kong, China.
authors: Dong-Yan
authors: DY
authors: Jin
authors: Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA 10104.
authors: Viktoriya
authors: V
authors: Syrovatkina
authors: Institut Curie, Centre National de la Recherche Scientifique, Paris 75005, France.
authors: Kathleen
authors: K
authors: Scheffler
authors: Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA 10104 Institut Curie, Centre National de la Recherche Scientifique, Paris 75005, France P.T.T.tranp@mail.med.upenn.edu chuanhai@hku.hk.
authors: Phong T
authors: PT
authors: Tran
authors: Department of Biochemistry, University of Hong Kong, Pokfulam, Hong Kong, China HKU-Shenzhen Institute of Research and Innovation, University of Hong Kong, Shenzhen, China P.T.T.tranp@mail.med.upenn.edu chuanhai@hku.hk.
authors: Chuanhai
authors: C
authors: Fu
mesh_terms: D020090:Chromosome Segregation; D015825:Chromosomes, Fungal / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D008938:Mitosis; D054730:Protein Interaction Domains and Motifs; D021381:Protein Transport; D012568:Schizosaccharomyces / Q000166:cytology / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000378:metabolism*; D008941:Spindle Apparatus / Q000378:metabolism*
chemical_list: C479626:Alp7 protein, S pombe; D008869:Microtubule-Associated Proteins; D029702:Schizosaccharomyces pombe Proteins