Three microtubule severing enzymes contribute to the "Pacman-flux" machinery that moves chromosomes.
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.
Zhang
Dong
D
Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
Rogers
Gregory C
GC
Buster
Daniel W
DW
Sharp
David J
DJ
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
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