BubR1 acetylation is essential in mitosis. Mice heterozygous for the acetylation-deficient BubR1 allele (K243R/+) spontaneously developed tumors with massive chromosome missegregations. K243R/+ mouse embryonic fibroblasts (MEFs) exhibited a weakened spindle assembly checkpoint (SAC) with shortened mitotic timing. The generation of the SAC signal was intact, as Mad2 localization to the unattached kinetochore (KT) was unaltered; however, because of the premature degradation of K243R-BubR1, the mitotic checkpoint complex disassociated prematurely in the nocodazoletreated condition, suggesting that maintenance of the SAC is compromised. BubR1 acetylation was also required to counteract excessive Aurora B activity at the KT for stable chromosome-spindle attachments. The association of acetylation-deficient BubR1 with PP2A-B56α phosphatase was reduced, and the phosphorylated Ndc80 at the KT was elevated in K243R/+ MEFs. In relation, there was a marked increase of micronuclei and p53 mutation was frequently detected in primary tumors of K243R/+ mice. Collectively, the combined effects of failure in chromosome- spindle attachment and weakened SAC cause genetic instability and cancer in K243R/+ mice. © 2013 Park et al.
CITATION STYLE
Park, I., Lee, H. ock, Choi, E., Lee, Y. K., Kwon, M. S., Min, J., … Lee, H. (2013). Loss of BubR1 acetylation causes defects in spindle assembly checkpoint signaling and promotes tumor formation. Journal of Cell Biology, 202(2), 295–309. https://doi.org/10.1083/jcb.201210099
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