Bridgin connects the outer kinetochore to centromeric chromatin

Nat Commun. 2021 Jan 8;12(1):146. doi: 10.1038/s41467-020-20161-9.

Abstract

The microtubule-binding outer kinetochore is coupled to centromeric chromatin through CENP-CMif2, CENP-TCnn1, and CENP-UAme1 linker pathways originating from the constitutive centromere associated network (CCAN) of the inner kinetochore. Here, we demonstrate the recurrent loss of most CCAN components, including certain kinetochore linkers during the evolution of the fungal phylum of Basidiomycota. By kinetochore interactome analyses in a model basidiomycete and human pathogen Cryptococcus neoformans, a forkhead-associated domain containing protein "bridgin" was identified as a kinetochore component along with other predicted kinetochore proteins. In vivo and in vitro functional analyses of bridgin reveal its ability to connect the outer kinetochore with centromeric chromatin to ensure accurate chromosome segregation. Unlike established CCAN-based linkers, bridgin is recruited at the outer kinetochore establishing its role as a distinct family of kinetochore proteins. Presence of bridgin homologs in non-fungal lineages suggests an ancient divergent strategy exists to bridge the outer kinetochore with centromeric chromatin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromatin / metabolism*
  • Chromatin Immunoprecipitation
  • Chromosome Segregation*
  • Cryptococcus neoformans / physiology*
  • Fungal Proteins / genetics
  • Fungal Proteins / isolation & purification
  • Fungal Proteins / metabolism*
  • Intravital Microscopy
  • Kinetochores / metabolism*
  • Recombinant Proteins / genetics
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / metabolism

Substances

  • Chromatin
  • Fungal Proteins
  • Recombinant Proteins