October 25, 2013

Targets of SIN drive cell division

Vanderbilt researchers have identified a key regulator of cell division.

(Wellcome Images)

Cytokinesis is the physical separation of daughter cells. Failure to complete cytokinesis can cause cell death or promote tumor formation.

In the yeast Schizosaccharomyces pombe – a leading model for studies of cytokinesis – the septation initiation network (SIN) controls the formation and stability of the actin and myosin-based cytokinetic ring (CR), which constricts to accomplish cell division. Targets of SIN signaling at the CR had not been described.

Kathy Gould, Ph.D., professor of Cell and Developmental Biology, and colleagues have now identified a direct target of SIN signaling: the formin protein Cdc12, which localizes to the cell middle and is essential for actin assembly in the CR. They report in the Oct. 1 issue of Genes & Development that the SIN protein kinase Sid2 phosphorylates Cdc12. They show that elimination of this modification leads to persistent Cdc12 clustering, which compromises CR assembly and stability leading to defects in cell division.

The findings identify a SIN-triggered oligomeric switch that regulates cytokinetic formin function during cell division.

This research was supported by grants from the National Institutes of Health (CA119925, GM079265, GM101035).

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