RRC ID 70429
Author Dong Q, Liu XL, Wang XH, Zhao Y, Chen YH, Li F.
Title Ccp1-Ndc80 switch at the N terminus of CENP-T regulates kinetochore assembly.
Journal Proc Natl Acad Sci U S A
Abstract Kinetochores, a protein complex assembled on centromeres, mediate chromosome segregation. In most eukaryotes, centromeres are epigenetically specified by the histone H3 variant CENP-A. CENP-T, an inner kinetochore protein, serves as a platform for the assembly of the outer kinetochore Ndc80 complex during mitosis. How CENP-T is regulated through the cell cycle remains unclear. Ccp1 (counteracter of CENP-A loading protein 1) associates with centromeres during interphase but delocalizes from centromeres during mitosis. Here, we demonstrated that Ccp1 directly interacts with CENP-T. CENP-T is important for the association of Ccp1 with centromeres, whereas CENP-T centromeric localization depends on Mis16, a homolog of human RbAp48/46. We identified a Ccp1-interaction motif (CIM) at the N terminus of CENP-T, which is adjacent to the Ndc80 receptor motif. The CIM domain is required for Ccp1 centromeric localization, and the CIM domain-deleted mutant phenocopies ccp1Δ. The CIM domain can be phosphorylated by CDK1 (cyclin-dependent kinase 1). Phosphorylation of CIM weakens its interaction with Ccp1. Consistent with this, Ccp1 dissociates from centromeres through all stages of the cell cycle in the phosphomimetic mutant of the CIM domain, whereas in the phospho-null mutant of the domain, Ccp1 associates with centromeres during mitosis. We further show that the phospho-null mutant disrupts the positioning of the Ndc80 complex during mitosis, resulting in chromosome missegregation. This work suggests that competitive exclusion between Ccp1 and Ndc80 at the N terminus of CENP-T via phosphorylation ensures precise kinetochore assembly during mitosis and uncovers a previously unrecognized mechanism underlying kinetochore assembly through the cell cycle.
Volume 118(48)
Published 2021-11-30
DOI 10.1073/pnas.2104459118
PII 2104459118
PMID 34810257
PMC PMC8640933
MeSH CDC2 Protein Kinase / metabolism Centromere / metabolism Centromere Protein A / genetics Chromosomal Proteins, Non-Histone / metabolism* Chromosomal Proteins, Non-Histone / physiology Chromosome Segregation Histones / metabolism Interphase Kinetochores / metabolism* Kinetochores / physiology Microtubule-Associated Proteins / metabolism* Microtubule-Associated Proteins / physiology Mitosis Phosphorylation Schizosaccharomyces / metabolism Schizosaccharomyces pombe Proteins / metabolism* Schizosaccharomyces pombe Proteins / physiology
IF 9.412
Yeast FY32201