Structure of the human inner kinetochore CCAN complex and its significance for human centromere organization.
Pesenti, M.E., Raisch, T., Conti, D., Walstein, K., Hoffmann, I., Vogt, D., Prumbaum, D., Vetter, I.R., Raunser, S., Musacchio, A.(2022) Mol Cell 82: 2113
- PubMed: 35525244 
- DOI: https://doi.org/10.1016/j.molcel.2022.04.027
- Primary Citation of Related Structures:  
7QOO - PubMed Abstract: 
Centromeres are specialized chromosome loci that seed the kinetochore, a large protein complex that effects chromosome segregation. A 16-subunit complex, the constitutive centromere associated network (CCAN), connects between the specialized centromeric chromatin, marked by the histone H3 variant CENP-A, and the spindle-binding moiety of the kinetochore. Here, we report a cryo-electron microscopy structure of human CCAN. We highlight unique features such as the pseudo GTPase CENP-M and report how a crucial CENP-C motif binds the CENP-LN complex. The CCAN structure has implications for the mechanism of specific recognition of the CENP-A nucleosome. A model consistent with our structure depicts the CENP-C-bound nucleosome as connected to the CCAN through extended, flexible regions of CENP-C. An alternative model identifies both CENP-C and CENP-N as specificity determinants but requires CENP-N to bind CENP-A in a mode distinct from the classical nucleosome octamer.
Organizational Affiliation: 
Department of Mechanistic Cell Biology, Max-Planck Institute of Molecular Physiology, Otto-Hahn-Straße 11, 44227 Dortmund, Germany.