Roshan, PoonamKuppa, SahitiMattice, Jenna R.Kaushik, VikasChadda, RahulPokhrel, NilishaTumala, Brunda R.Biswas, AparnaBothner, BrianAntony, EdwinOriganti, Sofia2023-07-122023-07-122023-05Roshan, P., Kuppa, S., Mattice, J.R. et al. An Aurora B-RPA signaling axis secures chromosome segregation fidelity. Nat Commun 14, 3008 (2023). https://doi.org/10.1038/s41467-023-38711-22041-1723https://scholarworks.montana.edu/handle/1/17962Errors in chromosome segregation underlie genomic instability associated with cancers. Resolution of replication and recombination intermediates and protection of vulnerable single-stranded DNA (ssDNA) intermediates during mitotic progression requires the ssDNA binding protein Replication Protein A (RPA). However, the mechanisms that regulate RPA specifically during unperturbed mitotic progression are poorly resolved. RPA is a heterotrimer composed of RPA70, RPA32 and RPA14 subunits and is predominantly regulated through hyperphosphorylation of RPA32 in response to DNA damage. Here, we have uncovered a mitosis-specific regulation of RPA by Aurora B kinase. Aurora B phosphorylates Ser-384 in the DNA binding domain B of the large RPA70 subunit and highlights a mode of regulation distinct from RPA32. Disruption of Ser-384 phosphorylation in RPA70 leads to defects in chromosome segregation with loss of viability and a feedback modulation of Aurora B activity. Phosphorylation at Ser-384 remodels the protein interaction domains of RPA. Furthermore, phosphorylation impairs RPA binding to DSS1 that likely suppresses homologous recombination during mitosis by preventing recruitment of DSS1-BRCA2 to exposed ssDNA. We showcase a critical Aurora B-RPA signaling axis in mitosis that is essential for maintaining genomic integrity.en-UScc-byhttps://creativecommons.org/licenses/by/4.0/aurorachromosome segregationchromosome fidelityArticle