biostudies-literaturePereira ALWellcome TrustPHS HHSNIGMS NIH HHS4526-42https://www.ebi.ac.uk/biostudies/studies/S-EPMC1635371biostudies-literatureUnknown17(10)CLASPs are widely conserved microtubule plus-end-tracking proteins with essential roles in the local regulation of microtubule dynamics. In yeast, Drosophila, and Xenopus, a single CLASP orthologue is present, which is required for mitotic spindle assembly by regulating microtubule dynamics at the kinetochore. In mammals, however, only CLASP1 has been directly implicated in cell division, despite the existence of a second paralogue, CLASP2, whose mitotic roles remain unknown. Here, we show that CLASP2 localization at kinetochores, centrosomes, and spindle throughout mitosis is remarkably similar to CLASP1, both showing fast microtubule-independent turnover rates. Strikingly, primary fibroblasts from Clasp2 knockout mice show numerous spindle and chromosome segregation defects that can be pMolecular biology of the cellMammalian CLASP1 and CLASP2 cooperate to ensure mitotic fidelity by regulating spindle and kinetochore function.PMC1635371073915R37 GM040198-22GMS 40198R37 GM040198Stepanova THergert PJRieder CLGaljart NSayas CLEarnshaw WCDuque CDrabek KMatos IPereira ALLince-Faria MPereira AJMaiato HMaia ARfalseMammalian CLASP1 and CLASP2 cooperate to ensure mitotic fidelity by regulating spindle and kinetochore function.CLASPs are widely conserved microtubule plus-end-tracking proteins with essential roles in the local regulation of microtubule dynamics. In yeast, Drosophila, and Xenopus, a single CLASP orthologue is present, which is required for mitotic spindle assembly by regulating microtubule dynamics at the kinetochore. In mammals, however, only CLASP1 has been directly implicated in cell division, despite the existence of a second paralogue, CLASP2, whose mitotic roles remain unknown. Here, we show that CLASP2 localization at kinetochores, centrosomes, and spindle throughout mitosis is remarkably similar to CLASP1, both showing fast microtubule-independent turnover rates. Strikingly, primary fibroblasts from Clasp2 knockout mice show numerous spindle and chromosome segregation defects that can be p2006-01-01T00:00:00Z2006 Oct2025-04-04T13:41:02.32Z2019-03-27T01:46:13ZS-EPMC16353711691451410.1091/mbc.e06-07-057910.1091/mbc.E06-07-0579