Condensation of MATCAP promotes CENP-E-dependent chromosome congression in mitosis

Accurate segregation of mitotic chromosomes requires pre-anaphase alignment driven by microtubule-based motor proteins. Tubulin detyrosination is essential to guide CENP-E-driven chromosome congression in mitosis. However, the mechanisms of action and physiochemical properties of the detyrosinases for decoding CENP-E motility remain elusive. Here we show that microtubule-associated tyrosine carboxypeptidase (MATCAP) undergoes intrinsically disordered region (IDR)-dependent liquid-liquid phase separation (LLPS) on microtubules to constitute the tubulin detyrosination machinery. These biomolecular condensates selectively enrich tubulin and CENP-E, thereby stabilizing kinetochore-microtubule attachments. Real-time imaging of cells expressing LLPS-deficient MATCAP mutants reveals the importance of MATCAP LLPS dynamics in mitotic chromosome alignment. Mechanistically, phase separation of MATCAP spatiotemporally couples tubulin detyrosination with CENP-E motility to ensure a robust chromosome alignment during mitosis. These findings delineate a signaling cascade that integrates phase separation and tubulin detyrosination with mitotic progression for the maintenance of genomic stability. MATCAP catalyzes tubulin tyrosine code essential for microtubule dynamics. Here the authors show that MATCAP undergoes condensation to consolidate tubulin decoding with CENP-E motility to ensure a robust metaphase alignment during mitosis.