title: Spatial signals link exit from mitosis to spindle position.
abstract: In budding yeast, if the spindle becomes mispositioned, cells prevent exit from mitosis by inhibiting the mitotic exit network (MEN). The MEN is a signaling cascade that localizes to spindle pole bodies (SPBs) and activates the phosphatase Cdc14. There are two competing models that explain MEN regulation by spindle position. In the 'zone model', exit from mitosis occurs when a MEN-bearing SPB enters the bud. The 'cMT-bud neck model' posits that cytoplasmic microtubule (cMT)-bud neck interactions prevent MEN activity. Here we find that 1) eliminating cMT- bud neck interactions does not trigger exit from mitosis and 2) loss of these interactions does not precede Cdc14 activation. Furthermore, using binucleate cells, we show that exit from mitosis occurs when one SPB enters the bud despite the presence of a mispositioned spindle. We conclude that exit from mitosis is triggered by a correctly positioned spindle rather than inhibited by improper spindle position.
authors.affiliation: David H Koch Institute for Integrative Cancer Research, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, United States.
authors.forename: Jill Elaine
authors.initials: JE
authors.lastname: Falk
authors.affiliation: Department of Biology, Indiana University, Bloomington, United States.
authors.forename: Dai
authors.initials: D
authors.lastname: Tsuchiya
authors.affiliation: Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, United States.
authors.forename: Jolien
authors.initials: J
authors.lastname: Verdaasdonk
authors.affiliation: Department of Biology, Indiana University, Bloomington, United States.
authors.forename: Soni
authors.initials: S
authors.lastname: Lacefield
authors.affiliation: Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, United States.
authors.forename: Kerry
authors.initials: K
authors.lastname: Bloom
authors.affiliation: David H Koch Institute for Integrative Cancer Research, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, United States.
authors.forename: Angelika
authors.identifier: 0000-0001-9837-0314
authors.initials: A
authors.lastname: Amon
mesh_terms: D018797:Cell Cycle Proteins / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism*; D008938:Mitosis; D008954:Models, Biological; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D064048:Spindle Pole Bodies / Q000378:metabolism*
chemical_list: C074860:CDC14 protein, S cerevisiae; D018797:Cell Cycle Proteins; D029701:Saccharomyces cerevisiae Proteins; D017027:Protein Tyrosine Phosphatases
keywords: CDC14; Cdc14 early anaphase release network; KIN4; S. cerevisiae; cell biology; mitotic exit network; spindle position checkpoint; zone model