An Iml3-Chl4 heterodimer links the core centromere to factors required for accurate chromosome segregation.
Publication Type:Journal Article
Source:Cell Rep, Volume 5, Issue 1, p.29-36 (2013)
Keywords:Amino Acid Sequence, Cell Cycle Proteins, Centromere, Chromosome Segregation, Crystallography, X-Ray, Cytoskeletal Proteins, DNA-Binding Proteins, Models, Molecular, Molecular Sequence Data, Nuclear Proteins, Point Mutation, Protein Structure, Secondary, Saccharomyces cerevisiae, Saccharomyces cerevisiae Proteins
<p>Accurate segregation of genetic material in eukaryotes relies on the kinetochore, a multiprotein complex that connects centromeric DNA with microtubules. In yeast and humans, two proteins-Mif2/CENP-C and Chl4/CNEP-N-interact with specialized centromeric nucleosomes and establish distinct but cross-connecting axes of chromatin-microtubule linkage. Proteins recruited by Chl4/CENP-N include a subset that regulates chromosome transmission fidelity. We show that Chl4 and a conserved member of this subset, Iml3, both from Saccharomyces cerevisiae, form a stable protein complex that interacts with Mif2 and Sgo1. We have determined the structures of an Iml3 homodimer and an Iml3-Chl4 heterodimer, which suggest a mechanism for regulating the assembly of this functional axis of the kinetochore. We propose that at the core centromere, the Chl4-Iml3 complex participates in recruiting factors, such as Sgo1, that influence sister chromatid cohesion and encourage sister kinetochore biorientation. </p>