7pii
Structure of the human CCAN CENP-A alpha-satellite complex
Structural highlights
FunctionCENPA_HUMAN Histone H3-like variant which exclusively replaces conventional H3 in the nucleosome core of centromeric chromatin at the inner plate of the kinetochore. Required for recruitment and assembly of kinetochore proteins, mitotic progression and chromosome segregation. May serve as an epigenetic mark that propagates centromere identity through replication and cell division. The CENPA-H4 heterotetramer can bind DNA by itself (in vitro).[1] [2] Publication Abstract from PubMedKinetochores assemble onto specialized centromeric CENP-A (centromere protein A) nucleosomes (CENP-A(Nuc)) to mediate attachments between chromosomes and the mitotic spindle. We describe cryo-electron microscopy structures of the human inner kinetochore constitutive centromere associated network (CCAN) complex bound to CENP-A(Nuc) reconstituted onto alpha-satellite DNA. CCAN forms edge-on contacts with CENP-A(Nuc), and a linker DNA segment of the alpha-satellite repeat emerges from the fully wrapped end of the nucleosome to thread through the central CENP-LN channel that tightly grips the DNA. The CENP-TWSX histone-fold module further augments DNA binding and partially wraps the linker DNA in a manner reminiscent of canonical nucleosomes. Our study suggests that the topological entrapment of the linker DNA by CCAN provides a robust mechanism by which kinetochores withstand both pushing and pulling forces exerted by the mitotic spindle. Structure of the human inner kinetochore bound to a centromeric CENP-A nucleosome.,Yatskevich S, Muir KW, Bellini D, Zhang Z, Yang J, Tischer T, Predin M, Dendooven T, McLaughlin SH, Barford D Science. 2022 May 20;376(6595):844-852. doi: 10.1126/science.abn3810. Epub 2022 , Apr 14. PMID:35420891[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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