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Publication Abstract from PubMed

Kinetochores are superprotein complexes that orchestrate chromosome segregation via a dynamic interaction with spindle microtubules. A physical connection between CENP-C and the Mis12-Ndc80-Knl1 (KMN) protein network is an important pathway that is used to assemble kinetochores on CENP-A nucleosomes. Multiple outer kinetochore components are phosphorylated by Aurora B kinase to activate the spindle assembly checkpoint (SAC) and to ensure accurate chromosome segregation. However, it is unknown whether Aurora B can phosphorylate inner kinetochore components to facilitate proper mitotic chromosome segregation. Here, we reported the structure of the fission yeast Schizosaccharomyces pombe Mis12-Nnf1 complex and showed that N-terminal residues 26-50 in Cnp3 (the CENP-C homolog of S. pombe) are responsible for interacting with the Mis12 complex. Interestingly, Thr28 of Cnp3 is a substrate of Ark1 (the Aurora B homolog of S. pombe), and phosphorylation impairs the interaction between the Cnp3 and Mis12 complex. The expression of a phosphorylation-mimicking Cnp3 mutant results in defective chromosome segregation due to improper kinetochore assembly. These results establish a previously uncharacterized regulatory mechanism involved in CENP-C-Mis12-facilitated kinetochore attachment error correction to ensure accurate chromosome segregation during mitosis.

Phosphorylation of CENP-C by Aurora B facilitates kinetochore attachment error correction in mitosis.,Zhou X, Zheng F, Wang C, Wu M, Zhang X, Wang Q, Yao X, Fu C, Zhang X, Zang J Proc Natl Acad Sci U S A. 2017 Dec 12;114(50):E10667-E10676. doi:, 10.1073/pnas.1710506114. Epub 2017 Nov 27. PMID:29180432^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.