CCSAP (centriole, cilia and spindle associated protein) is a microtubule-binding protein with primary roles in mitotic spindle regulation and centriole biology. Mechanistically, CCSAP stabilizes microtubules by colocalizing with polyglutamylated microtubules and maintaining NUMA1 at spindle poles, thereby inhibiting microtubule depolymerization during mitosis 1. CCSAP shares a conserved repeat motif required for microtubule binding with MDM1, another centriole-associated protein 2. Additionally, CCSAP functions as a major regulator of tubulin glutamylation by forming a complex with TTLL5 glutamylases, promoting their activity and relocalization toward microtubules 3. Disease relevance includes altered CCSAP methylation in sporadic amyotrophic lateral sclerosis patients 4 and dysregulated expression in pre-eclamptic placentae 5. Clinically, CCSAP upregulation by LIN9 transcription factor contributes to paclitaxel resistance in triple-negative breast cancer, with LIN9 knockdown or BET inhibitor treatment reversing drug resistance by reducing CCSAP expression 6. These findings suggest CCSAP as a potential therapeutic target in cancer drug resistance and neurological diseases.