CLASP1 (cytoplasmic linker associated protein 1) is a microtubule plus-end tracking protein that plays critical roles in microtubule dynamics regulation and cellular organization. The protein contains distinct TOG domains (TOG1 and TOG2) with specialized functions - TOG1 lacks microtubule-binding activity while TOG2 has a convex architecture that may engage hyper-curved tubulin states to limit microtubule catastrophe and promote rescue 1. During mitosis, CLASP1 forms temporal complexes at kinetochores: early mitosis involves a Kif2b-CLASP1 complex promoting chromosome 2 and attachment error correction, while metaphase features an astrin-CLASP1 complex that stabilizes kinetochore-microtubule attachments and silences the spindle assembly checkpoint 2. CLASP1 cooperates with CLASP2 to ensure mitotic fidelity, with knockout cells showing chromosome 2 defects and chr2 instability 3. In meiosis, CLASP1 regulates spindle organization and cytokinesis through interactions with PLK1 and DYNC1I1 4. Clinically, biallelic CLASP1 variants cause a neurodevelopmental disorder characterized by primary microcephaly, severe developmental delay, refractory epilepsy, and distinctive brain malformations including lissencephaly 5. Additionally, CLASP1 shows unexpected roles in radiation response and S-phase regulation in cancer cells 6.