Sequential pathways preserve kinetochore integrity in meiosis

Kinetochores connect chromosomes to spindle microtubules, but how their integrity is maintained as they are remodelled during meiosis remains poorly understood. Here, we identify three distinct pathways linking centromeric chromatin to the outer kinetochore in budding yeast, mediated by the Ctf19 complex (Ctf19c CCAN ), Mif2 CENP-C and binding of Okp1 CENP-Q -Ame1 CENP-U to the Cse4 CENP-A essential N-terminal domain (END). Although partially redundant during mitosis, all three connections are required during meiosis, with distinct temporal requirements. The assembled Ctf19c CCAN and Mif2 CENP-C -dependent pathways maintain kinetochore integrity from meiotic entry, while Cse4 CENP-A -Okp1 CENP-Q -Ame1 CENP-U binding becomes critical during prophase and the meiotic divisions. We further show that Ipl1 Aurora B maintains kinetochore integrity independently of Ctf19c CCAN and provide evidence for an outer kinetochore-associated Ipl1 Aurora B pool. Strikingly, Cse4 CENP-A phosphomimetic mutations that restore kinetochore integrity upon Ipl1 Aurora B depletion instead exacerbate defects in cells lacking Ctf19c CCAN . Our findings suggest that phosphorylation of the Cse4 CENP-A N-terminal domain (NTD) by Ipl1 Aurora B may regulate the use of alternative centromere-kinetochore connections to adapt to the changing requirements of meiosis.