Secretion for cytokinesis

The actomyosin contractile ring involved in separating a dividing cell in two only gets so far. The job is finished, according to work from Adam Gromley, Stephen Doxsey (University of Massachusetts Medical Center, Worcester, MA), and colleagues, by a burst of secretory vesicle fusion.Doxsey's group was looking for a function for a vertebrate centrosomal protein called centriolin. A defect in cytokinesis was not what they expected to find when they knocked down centriolin function, but there it was. “We saw a thin wisp of cytoplasm retained between [daughter] cells,” says Doxsey.

In wild-type cells, this normally transient wisp harbored a ring of centriolin, which then recruited several components of the secretory pathway, including the exocyst. Later, SNARE proteins followed.

Unlike the actomyosin ring, the...