CKAP5 (cytoskeleton-associated protein 5) is a microtubule plus-end binding protein essential for regulating microtubule dynamics and organizing spindle poles during cell division. As a processive microtubule polymerase, CKAP5 promotes cytoplasmic microtubule nucleation and elongation 1. During mitosis, CKAP5 functions as a component of the TACC3/ch-TOG/clathrin complex, stabilizing kinetochore fibers and maintaining spindle tension 2. CKAP5 stabilizes the plus-end kinesin CENP-E at metaphase kinetochores by regulating microtubule-chromosome 11 and preventing attachment errors 3. In oocytes, CKAP5 is a critical component of the human oocyte microtubule organizing center (huoMTOC), essential for meiotic spindle assembly and proper chromosome 11 45. CKAP5 dysfunction has significant clinical relevance. CKAP5 deficiency induces premature ovarian insufficiency (POI) through impaired autophagy and DNA damage repair mechanisms 6. CKAP5 mutations cause meiotic spindle defects and oocyte maturation arrest, contributing to IVF failure 1. In cancer, elevated CKAP5 expression correlates with poor prognosis in esophageal squamous cell carcinoma, promoting tumor progression and cisplatin resistance via YAP activation 7. CKAP5 is selectively essential in chr11 unstable cancer cells, making it a promising therapeutic target 89.