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A dual role for Bub1 in the spindle checkpoint and chromosome congression
Author(s) -
Meraldi Patrick,
Sorger Peter K
Publication year - 2005
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/sj.emboj.7600641
Subject(s) - bub1 , kinetochore , spindle checkpoint , biology , microbiology and biotechnology , chromosome segregation , aurora b kinase , anaphase , microtubule , genetics , chromosome , gene
The spindle checkpoint ensures faithful chromosome segregation by linking the onset of anaphase to the establishment of bipolar kinetochore–microtubule attachment. The checkpoint is mediated by a signal transduction system comprised of conserved Mad, Bub and other proteins. In this study, we use live‐cell imaging coupled with RNA interference to investigate the functions of human Bub1. We find that Bub1 is essential for checkpoint control and for correct chromosome congression. Bub1 depletion leads to the accumulation of misaligned chromatids in which both sister kinetochores are linked to microtubules in an abnormal fashion, a phenotype that is unique among Mad and Bub depletions. Bub1 is similar to the Aurora B/Ipl1p kinase in having roles in both the checkpoint and microtubule binding. However, human Bub1 and Aurora B are recruited to kinetochores independently of each other and have an additive effect when depleted simultaneously. Thus, Bub1 and Aurora B appear to function in parallel pathways that promote formation of stable bipolar kinetochore–microtubule attachments.