December 13, 2013

Manager of mitotic stress

The protein CK1 delays cell division to avoid the generation of defects that drive tumorigenesis.

Illustration of a dividing cell. (Wellcome Images)

The accurate partitioning of genetic material is critical during cell division; failures can cause chromosomal defects that drive tumorigenesis. A series of cell-cycle “checkpoints” guard cells against defects by relaying signals that delay or prevent cell division when problems are detected.

Kathy Gould, Ph.D., professor of Cell and Developmental Biology, and colleagues have discovered that the conserved protein kinase CK1 is a crucial component of a cell-cycle checkpoint pathway. In the fission yeast S. pombe, they found that CK1 phosphorylates the protein Sid4, priming it for ubiquitination by Dma1 – a ubiquitin protein ligase. Sid4 ubiquitination delays the ability of a critical cell cycle regulator, polo-like kinase, to promote cytokinesis. They demonstrated that like Dma1, CK1 accumulates at spindle pole bodies (organizing units for cell division) and associates with spindle pole body components during mitotic arrest.

The findings, reported in Current Biology, highlight a novel function for the highly conserved kinase CK1 as part of a signaling pathway that delays cell division when cells are under conditions of mitotic stress.

This research was supported in part by the Howard Hughes Medical Institute and by a grant from the National Institutes of Health (GM008554).

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