Menon, Manoj B.Sawada, AkihiroChaturvedi, AnuharMishra, PoojaSchuster-Gossler, KarinGalla, MelanieSchambach, AxelGossler, AchimFörster, ReinholdHeuser, MichaelKotlyarov, AlexeyKinoshita, MakotoGaestel, Matthias2014-09-082014Menon, M. B., A. Sawada, A. Chaturvedi, P. Mishra, K. Schuster-Gossler, M. Galla, A. Schambach, et al. 2014. “Genetic Deletion of SEPT7 Reveals a Cell Type-Specific Role of Septins in Microtubule Destabilization for the Completion of Cytokinesis.” PLoS Genetics 10 (8): e1004558. doi:10.1371/journal.pgen.1004558. http://dx.doi.org/10.1371/journal.pgen.1004558.1553-7390http://nrs.harvard.edu/urn-3:HUL.InstRepos:12785892Cytokinesis terminates mitosis, resulting in separation of the two sister cells. Septins, a conserved family of GTP-binding cytoskeletal proteins, are an absolute requirement for cytokinesis in budding yeast. We demonstrate that septin-dependence of mammalian cytokinesis differs greatly between cell types: genetic loss of the pivotal septin subunit SEPT7 in vivo reveals that septins are indispensable for cytokinesis in fibroblasts, but expendable in cells of the hematopoietic system. SEPT7-deficient mouse embryos fail to gastrulate, and septin-deficient fibroblasts exhibit pleiotropic defects in the major cytokinetic machinery, including hyperacetylation/stabilization of microtubules and stalled midbody abscission, leading to constitutive multinucleation. We identified the microtubule depolymerizing protein stathmin as a key molecule aiding in septin-independent cytokinesis, demonstrated that stathmin supplementation is sufficient to override cytokinesis failure in SEPT7-null fibroblasts, and that knockdown of stathmin makes proliferation of a hematopoietic cell line sensitive to the septin inhibitor forchlorfenuron. Identification of septin-independent cytokinesis in the hematopoietic system could serve as a key to identify solid tumor-specific molecular targets for inhibition of cell proliferation.en-USBiology and Life SciencesCell BiologyCell ProcessesCell Cycle and Cell DivisionCytokinesisCell DeathCell ProliferationMicrotubule PolymerizationCellular Structures and OrganellesCell NucleusGeneticsGene DisruptionMolecular GeneticsMolecular BiologyPhysiologyHematopoietic SystemModel OrganismsAnimal ModelsMouse ModelsJournal Article2014-09-0810.1371/journal.pgen.1004558