Failure to accurately partition genetic material during cell division causes aneuploidy and drives tumorigenesis . Cell-cycle checkpoints safeguard cells from such catastrophes by impeding cell-cycle progression when mistakes arise. FHA-RING E3 ligases, including human RNF8  and CHFR  and fission yeast Dma1 , relay checkpoint signals by binding phosphorylated proteins via their FHA domains and promoting ubiquitination of downstream targets . Upon mitotic checkpoint activation, S. pombe Dma1 concentrates at spindle pole bodies (SPBs) in an FHA-dependent manner and ubiquitinates Sid4, a scaffold of Polo kinase, to suspend cytokinesis . However, the kinase or kinases that phosphoprime Sid4 for Dma1-mediated ubiquitination are unknown. Here, we report that the highly conserved protein kinase CK1 transmits the signal necessary to stall cytokinesis by phosphopriming Sid4 for Dma1-mediated ubiquitination. Like Dma1, CK1 accumulates at SPBs during a mitotic arrest and associates stably with SPB components, including Sid4. Our results establish CK1 as an integral component of a mitotic, ubiquitin-mediated checkpoint pathway. © 2013 Elsevier Ltd.
Publication Source (Journal or Book title)
Johnson, A., Chen, J., & Gould, K. (2013). CK1 is required for a mitotic checkpoint that delays cytokinesis. Current Biology, 23 (19), 1920-1926. https://doi.org/10.1016/j.cub.2013.07.077