title: Direct binding of Cenp-C to the Mis12 complex joins the inner and outer kinetochore.
abstract: Kinetochores are proteinaceous scaffolds implicated in the formation of load-bearing attachments of chromosomes to microtubules during mitosis. Kinetochores contain distinct chromatin- and microtubule-binding interfaces, generally defined as the inner and outer kinetochore, respectively (reviewed in). The constitutive centromere-associated network (CCAN) and the Knl1-Mis12-Ndc80 complexes (KMN) network are the main multisubunit protein assemblies in the inner and outer kinetochore, respectively. The point of contact between the CCAN and the KMN network is unknown. Cenp-C is a conserved CCAN component whose central and C-terminal regions have been implicated in chromatin binding and dimerization. Here, we show that a conserved motif in the N-terminal region of Cenp-C binds directly and with high affinity to the Mis12 complex. Expression in HeLa cells of the isolated N-terminal motif of Cenp-C prevents outer kinetochore assembly, causing chromosome missegregation. The KMN network is also responsible for kinetochore recruitment of the components of the spindle assembly checkpoint, and we observe checkpoint impairment in cells expressing the Cenp-C N-terminal segment. Our studies unveil a crucial and likely universal link between the inner and outer kinetochore.
authors.affiliation: Department of Experimental Oncology, European Institute of Oncology, Milan, Italy.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Screpanti
authors.forename: Anna
authors.initials: A
authors.lastname: De Antoni
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Alushin
authors.forename: Arsen
authors.initials: A
authors.lastname: Petrovic
authors.forename: Tiziana
authors.initials: T
authors.lastname: Melis
authors.forename: Eva
authors.initials: E
authors.lastname: Nogales
authors.forename: Andrea
authors.initials: A
authors.lastname: Musacchio
mesh_terms: D002850:Chromatography, Gel; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism*; D020090:Chromosome Segregation / Q000502:physiology*; D004591:Electrophoresis, Polyacrylamide Gel; D005455:Fluorescent Antibody Technique; D019084:Fluorescent Antibody Technique, Indirect; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D007091:Image Processing, Computer-Assisted; D015151:Immunoblotting; D018386:Kinetochores / Q000378:metabolism*; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D046912:Multiprotein Complexes / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics
chemical_list: D002868:Chromosomal Proteins, Non-Histone; C492664:MIS12 protein, human; D008869:Microtubule-Associated Proteins; D046912:Multiprotein Complexes; C060905:centromere protein C; D049452:Green Fluorescent Proteins