title: Stable kinetochore-microtubule attachment is sufficient to silence the spindle assembly checkpoint in human cells.
abstract: During mitosis, duplicated sister chromatids attach to microtubules emanating from opposing sides of the bipolar spindle through large protein complexes called kinetochores. In the absence of stable kinetochore-microtubule attachments, a cell surveillance mechanism known as the spindle assembly checkpoint (SAC) produces an inhibitory signal that prevents anaphase onset. Precisely how the inhibitory SAC signal is extinguished in response to microtubule attachment remains unresolved. To address this, we induced formation of hyper-stable kinetochore-microtubule attachments in human cells using a non-phosphorylatable version of the protein Hec1, a core component of the attachment machinery. We find that stable attachments are sufficient to silence the SAC in the absence of sister kinetochore bi-orientation and strikingly in the absence of detectable microtubule pulling forces or tension. Furthermore, we find that SAC satisfaction occurs despite the absence of large changes in intra-kinetochore distance, suggesting that substantial kinetochore stretching is not required for quenching the SAC signal.
authors.affiliation: Cell and Molecular Biology Program, Colorado State University, Fort Collins, Colorado 80523, USA.
authors.forename: Eric C
authors.initials: EC
authors.lastname: Tauchman
authors.affiliation: Department of Statistics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
authors.forename: Frederick J
authors.initials: FJ
authors.lastname: Boehm
authors.affiliation: Cell and Molecular Biology Program, Colorado State University, Fort Collins, Colorado 80523, USA.|Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, USA.
authors.forename: Jennifer G
authors.initials: JG
authors.lastname: DeLuca
mesh_terms: D020090:Chromosome Segregation; D003598:Cytoskeletal Proteins; D006367:HeLa Cells; D006801:Humans; D018386:Kinetochores / Q000378:metabolism*; D059566:M Phase Cell Cycle Checkpoints; D008870:Microtubules / Q000235:genetics / Q000378:metabolism*; D008938:Mitosis; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D008941:Spindle Apparatus / Q000235:genetics / Q000378:metabolism*
chemical_list: D003598:Cytoskeletal Proteins; C120529:NDC80 protein, human; D009687:Nuclear Proteins