Plays a central role in chromosome cohesion during meiosis and mitosis by preventing premature dissociation of cohesin complex from centromeres after prophase, when most of cohesin complex dissociates from chromosomes arms. May act by protecting or Rad21 from cleavage by Sse/separase. Required during meiosis in both males and females. Homodimer. Interacts with Incenp. Localizes to the centromere of meiotic and mitotic chromosomes (PubMed:9490715, PubMed:10654079). During meiosis, it assembles onto centromeres during prometaphase I, remains attached until anaphase II, during which it is displaced from centromeres without being degraded (PubMed:9490715). Localization onto centromeres is independent of kinetochore formation and cohesin complex (PubMed:10985388). Expressed both maternally and zygotically. Present throughout embryogenesis and larval stages. Phosphorylation by polo-like kinase (PLK) on Thr-331 antagonizes cohesive function. Phosphorylation on Thr-331 at the metaphase anaphase transition leads to its dissociation from centromeres. In contrast, phosphorylation by aurB/ial on either Ser-124, Ser-125 or Ser-126 is required for association with centromeres. Belongs to the shugoshin family.