title: Three microtubule severing enzymes contribute to the "Pacman-flux" machinery that moves chromosomes.
abstract: Chromosomes move toward mitotic spindle poles by a Pacman-flux mechanism linked to microtubule depolymerization: chromosomes actively depolymerize attached microtubule plus ends (Pacman) while being reeled in to spindle poles by the continual poleward flow of tubulin subunits driven by minus-end depolymerization (flux). We report that Pacman-flux in Drosophila melanogaster incorporates the activities of three different microtubule severing enzymes, Spastin, Fidgetin, and Katanin. Spastin and Fidgetin are utilized to stimulate microtubule minus-end depolymerization and flux. Both proteins concentrate at centrosomes, where they catalyze the turnover of gamma-tubulin, consistent with the hypothesis that they exert their influence by releasing stabilizing gamma-tubulin ring complexes from minus ends. In contrast, Katanin appears to function primarily on anaphase chromosomes, where it stimulates microtubule plus-end depolymerization and Pacman-based chromatid motility. Collectively, these findings reveal novel and significant roles for microtubule severing within the spindle and broaden our understanding of the molecular machinery used to move chromosomes.
authors: Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
authors: Dong
authors: D
authors: Zhang
authors: Gregory C
authors: GC
authors: Rogers
authors: Daniel W
authors: DW
authors: Buster
authors: David J
authors: DJ
authors: Sharp
mesh_terms: D000074183:ATPases Associated with Diverse Cellular Activities; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000705:Anaphase; D000818:Animals; D002460:Cell Line; D018385:Centrosome / Q000378:metabolism; D020090:Chromosome Segregation; D002875:Chromosomes / Q000378:metabolism*; D029721:Drosophila Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology / Q000378:metabolism*; D000074201:Katanin; D008677:Metaphase; D008869:Microtubule-Associated Proteins; D008870:Microtubules / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism; D008941:Spindle Apparatus / Q000378:metabolism*; D014404:Tubulin / Q000378:metabolism
chemical_list: D029721:Drosophila Proteins; C519702:Kat60 protein, Drosophila; D008869:Microtubule-Associated Proteins; D009687:Nuclear Proteins; D014404:Tubulin; D000251:Adenosine Triphosphatases; C501874:spas protein, Drosophila; D000074183:ATPases Associated with Diverse Cellular Activities; C519701:Fign protein, Drosophila; D000074201:Katanin