Shugoshin proteins are evolutionarily conserved across eukaryotes, with some species-specific cellular functions, ensuring the fidelity of chromosome segregation. They act as adaptors at various subcellular locales to mediate several proteinprotein interactions in a spatio-temporal manner. Here, we characterize shugoshin (Sgo1) in the human fungal pathogen Candida albicans. We observe that Sgo1 retains its centromeric localization and performs its conserved functions of regulating the sister chromatid biorientation, centromeric condensin localization, and maintenance of chromosomal passenger complex (CPC). We identify novel roles of Sgo1 as a spindle assembly checkpoint (SAC) component with functions in maintaining a prolonged SAC response by retaining Mad2 and Bub1 at the kinetochores in response to improper kinetochore-microtubule attachments. Strikingly, we discover the in vivo localization of Sgo1 along the length of the mitotic spindle. Our results indicate that Sgo1 performs a hitherto unknown function of facilitating timely disassembly of the mitotic spindle in C. albicans. To summarize, this study unravels a unique functional adaptation of shugoshin in maintaining genomic stability.

Shugoshin proteins are evolutionary conserved across eukaryotes with some species-specific cellular functions ensuring the fidelity of chromosome segregation. Shugoshin being present at various subcellular locales, acts as an adaptor to mediate various protein-protein interactions in a spatio-temporal manner. Here, we characterize shugoshin (Sgo1) in the human fungal pathogen, Candida albicans. Interestingly, we discover a novel in vivo localization of Sgo1 along the length of the mitotic spindle. Further, Sgo1 performs a hitherto unknown function of facilitating timely disassembly of spindle in this organism. We observe that Sgo1 retains its centromeric localization and performs its conserved functions that include regulating the centromeric condensin localization, chromosome passenger complex (CPC) maintenance and sister chromatid biorientation. We identify novel roles of Sgo1 as a spindle assembly checkpoint (SAC) component with functions in maintaining the SAC proteins, Mad2 and Bub1, at the kinetochores, in response to faulty kinetochore-microtubule attachments. These findings provide an excellent evidence of the functional rewiring of shugoshin in maintaining genomic stability.