title: Multiple assembly mechanisms anchor the KMN spindle checkpoint platform at human mitotic kinetochores.
abstract: During mitosis, the spindle checkpoint senses kinetochores not properly attached to spindle microtubules and prevents precocious sister-chromatid separation and aneuploidy. The constitutive centromere-associated network (CCAN) at inner kinetochores anchors the KMN network consisting of Knl1, the Mis12 complex (Mis12C), and the Ndc80 complex (Ndc80C) at outer kinetochores. KMN is a critical kinetochore receptor for both microtubules and checkpoint proteins. Here, we show that nearly complete inactivation of KMN in human cells through multiple strategies produced strong checkpoint defects even when all kinetochores lacked microtubule attachment. These KMN-inactivating strategies reveal multiple KMN assembly mechanisms at human mitotic kinetochores. In one mechanism, the centromeric kinase Aurora B phosphorylates Mis12C and strengthens its binding to the CCAN subunit CENP-C. In another, CENP-T contributes to KMN attachment in a CENP-H-I-K-dependent manner. Our study provides insights into the mechanisms of mitosis-specific assembly of the checkpoint platform KMN at human kinetochores.
authors.affiliation: Howard Hughes Medical Institute, Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390.
authors.forename: Soonjoung
authors.initials: S
authors.lastname: Kim
authors.affiliation: Howard Hughes Medical Institute, Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390 hongtao.yu@utsouthwestern.edu.
authors.forename: Hongtao
authors.initials: H
authors.lastname: Yu
mesh_terms: D064107:Aurora Kinase B / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism; D003598:Cytoskeletal Proteins; D006367:HeLa Cells; D006801:Humans; D018386:Kinetochores / Q000378:metabolism*; D059566:M Phase Cell Cycle Checkpoints; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D021122:Protein Subunits / Q000378:metabolism
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D003598:Cytoskeletal Proteins; C532764:DSN1 protein, human; C472643:Knl1 protein, human; C492664:MIS12 protein, human; D008869:Microtubule-Associated Proteins; C120529:NDC80 protein, human; D009687:Nuclear Proteins; D021122:Protein Subunits; C576921:AURKB protein, human; D064107:Aurora Kinase B