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Assembly and phospho-regulatory mechanisms of the budding yeast outer kinetochore KMN complex

ABSTRACT: Crosslinking of KMN outer kinetochore complex. During mitosis and meiosis kinetochores mediate interactions between chromosomes and spindle microtubules. Kinetochores are multi-megadalton protein complexes essential for chromosome segregation in all eukaryotes, however recent structural, functional, and evolutionary studies have revealed divergent mechanisms of kinetochore assembly. In this study, we use cryo-EM to understand the structural mechanisms by which the budding yeast microtubule-binding outer kinetochore KMN complex assembles, and how its interactions with the centromere-binding inner kinetochore are regulated. The ten-subunit KMN complex comprises three subcomplexes: Knl1c, Mis12cMtw1c and Ndc80c. We show that α-helical motifs in the C-termini of the Mis12cMtw1c subunits Dsn1, Mis12Mtw1 and Pmf1Nnf1 bind Knl1c and Ndc80c. At the opposite end of the Mis12cMtw1c stalk, an N-terminal auto-inhibitory segment of Dsn1 (Dsn1AI) folds into two α-helices that engage its head 1 domain, thereby occluding binding sites for the inner kinetochore subunits CENP-CMif2 and CENP-UAme1, reducing their affinity for Mis12cMtw1. Our structure reveals how Aurora BIpl1 phosphorylation of Dsn1AI would release this auto-inhibition to substantially strengthen pre-existing connections between the inner and outer kinetochore.

INSTRUMENT(S):

ORGANISM(S): Saccharomyces Cerevisiae (baker's Yeast)

SUBMITTER: Tomos Morgan

LAB HEAD: David Barford

PROVIDER: PXD072662 | Pride | 2026-03-16

REPOSITORIES: Pride

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			Action	DRS
	KM_SDA_FAIMS5065_13.mgf	Mgf
	KM_SDA_FAIMS5065_13.raw	Raw
	KM_SDA_FAIMS5065_14.mgf	Mgf
	KM_SDA_FAIMS5065_14.raw	Raw
	KM_SDA_FAIMS5065_15.mgf	Mgf

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