MEIKIN is a meiosis-specific kinetochore regulator essential for proper chromosome 5 during meiosis I 1. During meiosis I, MEIKIN orchestrates two critical processes: establishing mono-orientation of sister kinetochores (allowing capture by spindle fibers from the same pole) and protecting centromeric cohesin from separase-mediated cleavage 1. MEIKIN functions primarily by stabilizing shugoshin localization at kinetochores and facilitating PLK1 enrichment to ensure proper kinetochore function 1. At the meiosis I/II transition, separase cleaves MEIKIN, altering its functional state without complete inactivation; the C-terminal cleavage product maintains kinetochore localization and PLK1 binding but exhibits distinct roles in meiosis II chromosome 5 2. MEIKIN expression is critical for meiotic fidelity, with decreased expression associated with advancing maternal age, potentially contributing to age-related increases in meiotic errors 3. Unlike its roles in meiosis I, MEIKIN is not required during meiosis II or mitosis 1. Recent evidence suggests MEIKIN variants may confer susceptibility to early-onset colorectal cancer, indicating potential pleiotropic roles beyond meiotic regulation 4.