title: Girds 'n' cleeks o' cytokinesis: microtubule sticks and contractile hoops in cell division.
abstract: Microtubules maintain an intimate relationship with the rings of anillin, septins and actomyosin filaments throughout cytokinesis. In Drosophila, peripheral microtubules emanating from the spindle poles contact the equatorial cell cortex to deliver the signal that initiates formation of the cytokinetic furrow. Mutations that affect microtubule stability lead to ectopic furrowing because peripheral microtubules contact inappropriate cortical sites. The PAV-KLP (Pavarotti-kinesin-like protein)/RacGAP50C (where GAP is GTPase-activating protein) centralspindlin complex moves towards the plus ends of microtubules to reach the cell equator. When RacGAP50C is tethered to the cell membrane, furrowing initiates at multiple non-equatorial sites, indicating that mis-localization of this single molecule is sufficient to promote furrowing. Furrow formation and ingression requires RhoA activation by the RhoGEF (guanine-nucleotide-exchange factor) Pebble, which interacts with RacGAP50C. RacGAP50C also binds anillin, which associates with actin, myosin and septins. Thus RacGAP50C plays a pivotal role during furrow formation by activating RhoA and linking the peripheral microtubules with the nascent rings through its interaction with anillin.
authors.affiliation: Cancer Research U.K. Cell Cycle Genetics Research Group, University of Cambridge, Department of Genetics, Downing Street, Cambridge CB2 3EH, UK. dmg25@mole.bio.cam.ac.uk
authors.forename: David M
authors.initials: DM
authors.lastname: Glover
authors.forename: Luisa
authors.initials: L
authors.lastname: Capalbo
authors.forename: Pier Paolo
authors.initials: PP
authors.lastname: D'Avino
authors.forename: Melanie K
authors.initials: MK
authors.lastname: Gatt
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Savoian
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Takeda
mesh_terms: D000818:Animals; D048749:Cytokinesis; D029721:Drosophila Proteins / Q000378:metabolism; D004331:Drosophila melanogaster / Q000166:cytology*; D020690:GTPase-Activating Proteins / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism*; D015398:Signal Transduction; D008941:Spindle Apparatus / Q000378:metabolism
chemical_list: D029721:Drosophila Proteins; D020690:GTPase-Activating Proteins; C502951:tum protein, Drosophila