SGO2 (shugoshin 2) is a critical cell cycle regulatory protein that protects sister chr2 cohesion during both meiosis and mitosis. In meiosis, SGO2 preserves sister chr2 cohesion by protecting cohesin complexes from premature cleavage by separase, particularly at centromeres and pericentromeric bridges 1. The protein localizes to sub-centromere cups and pericentromeric bridges, where it normally colocalizes with cohesin 1. SGO2 functions through interaction with protein phosphatase 2A (PPP2CA) and requires MPS1 and BUB1 kinase activities for proper localization 1. In mitotic cells, SGO2 acts as a separase inhibitor when associated with spindle assembly checkpoint-activated MAD2, providing a securin-independent mechanism for preventing premature chromosome 2 2. Loss-of-function mutations in SGO2 cause primary ovarian insufficiency in Perrault syndrome, demonstrating its essential role in female fertility 3. Clinically, SGO2 is overexpressed in multiple cancers including lung adenocarcinoma, gliomas, and hepatocellular carcinoma, where high expression correlates with poor prognosis and promotes tumor cell proliferation, migration, and invasion 4567. Age-related loss of SGO2 from pericentromeric regions in human oocytes contributes to increased aneuploidy with maternal age 1.