Chromosomal Passenger Complex-Nucleosome Interaction Ensures Centromere Integrity and Chromosome Segregation Fidelity

The chromosomal passenger complex (CPC; Borealin-Survivin-INCENP-Aurora B kinase) ensures accurate chromosome segregation by orchestrating sister chromatid cohesion, error-correction of kinetochore-microtubule attachments, and spindle assembly checkpoint. Correct spatiotemporal regulation of CPC localization is critical for its function. Phosphorylations of Histone H3 Thr3 and Histone H2A Thr120 and modification-independent nucleosome interactions involving Survivin and Borealin contribute to CPC centromere enrichment. However, mechanistic basis for how various nucleosome binding elements collectively contribute to CPC centromere enrichment and whether CPC has any non-catalytic role at centromere remain open questions. Combining a high-resolution cryoEM structure of CPC-bound H3Thr3ph nucleosome with atomic force microscopy and biochemical and cellular assays, we demonstrate that CPC employs multipartite interactions, which facilitate its engagement at nucleosome acidic patch and DNA entry-exit site. Perturbing the CPC-nucleosome interaction compromises chromatin protection against MNase digestion in vitro, centromeric chromatin stability and error-free chromosome segregation in vivo. Our work suggests a non-catalytic chromatin stabilizing role of CPC in maintaining centromeric chromatin features critical for kinetochore function.

Anjitha Gireesh, Maria Alba Abad & Ryu-Suke Nozawa (2025). Chromosomal Passenger Complex-Nucleosome Interaction Ensures Centromere Integrity and Chromosome Segregation Fidelity. BioStudies, S-BSST2202. Retrieved from https://www.ebi.ac.uk/biostudies/studies/S-BSST2202