Taxol-stabilized microtubules can position the cytokinetic furrow in mammalian cells.
How microtubules act to position the plane of cell division during cytokinesis is a topic of much debate. Recently, we showed that a subpopulation of stable microtubules extends past chromosomes and interacts with the cell cortex at the site of furrowing, suggesting that these stabilized microtubules may stimulate contractility. To test the hypothesis that stable microtubules can position furrows, we used taxol to rapidly suppress microtubule dynamics during various stages of mitosis in PtK1 cells. Cells with stabilized prometaphase or metaphase microtubule arrays were able to initiate furrowing when induced into anaphase by inhibition of the spindle checkpoint. In these cells, few microtubules contacted the cortex. Furrows formed later than usual, were often aberrant, and did not progress to completion. Images showed that furrowing correlated with the presence of one or a few stable spindle microtubule plus ends at the cortex. Actin, myosin II, and anillin were all concentrated in these furrows, demonstrating that components of the contractile ring can be localized by stable microtubules. Inner centromere protein (INCENP) was not found in these ingressions, confirming that INCENP is dispensable for furrow positioning. Taxol-stabilization of the numerous microtubule-cortex interactions after anaphase onset delayed furrow initiation but did not perturb furrow positioning. We conclude that taxol-stabilized microtubules can act to position the furrow and that loss of microtubule dynamics delays the timing of furrow onset and prevents completion. We discuss our findings relative to models for cleavage stimulation.
Shannon
Katie B
KB
Department of Biology, University of North Carolina, Chapel Hill, NC 27599-3280, USA. ktphd@email.unc.edu
Canman
Julie C
JC
Ben Moree
C
C
Tirnauer
Jennifer S
JS
Salmon
E D
ED
D000705:Anaphase / Q000187:drug effects; D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D002450:Cell Communication / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D048749:Cytokinesis / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D007150:Immunohistochemistry; D008870:Microtubules / Q000737:chemistry / Q000187:drug effects* / Q000502:physiology*; D017239:Paclitaxel / Q000494:pharmacology*; D048328:Potoroidae; D008941:Spindle Apparatus / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism
D000972:Antineoplastic Agents, Phytogenic; D017239:Paclitaxel