title: The dynamics of microtubule minus ends in the human mitotic spindle.
abstract: During mitotic spindle assembly, γ-tubulin ring complexes (γTuRCs) nucleate microtubules at centrosomes, around chromosomes, and, by interaction with augmin, from pre-existing microtubules. How different populations of microtubules are organized to form a bipolar spindle is poorly understood, in part because we lack information on the dynamics of microtubule minus ends. Here we show that γTuRC is associated with minus ends of non-centrosomal spindle microtubules. Recruitment of γTuRC to spindles occurs preferentially at pole-distal regions, requires nucleation and/or interaction with minus ends, and is followed by sorting of minus-end-bound γTuRC towards the poles. Poleward movement of γTuRC exceeds k-fibre flux, involves the motors dynein, HSET (also known as KIFC1; a kinesin-14 family member) and Eg5 (also known as KIF11; a kinesin-5 family member), and slows down in pole-proximal regions, resulting in the accumulation of minus ends. Thus, in addition to nucleation, γTuRC actively contributes to spindle architecture by organizing microtubule minus ends.
authors: Nicolas
authors: N
authors: Lecland
authors: Jens
authors: J
authors: Lüders
mesh_terms: D016764:Cell Polarity / Q000235:genetics / Q000502:physiology; D018385:Centrosome / Q000378:metabolism; D004398:Dyneins / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D016547:Kinesins / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D008870:Microtubules / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D050505:Mutant Proteins / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D008941:Spindle Apparatus / Q000235:genetics / Q000378:metabolism*; D014404:Tubulin / Q000235:genetics / Q000378:metabolism
chemical_list: C470243:KIF11 protein, human; C486566:KIFC1 protein, human; D008869:Microtubule-Associated Proteins; D050505:Mutant Proteins; C509189:NEDD1 protein, human; D034741:RNA, Small Interfering; D014404:Tubulin; D004398:Dyneins; D016547:Kinesins