A New Understanding: How Two Cells Know When to Fuse

Research from the Rose lab published recently in the Journal of Cell Biology reveals a novel mechanism for how two mating yeast cells detect when they are in contact and trigger cell fusion.

In the article, entitled,”Membrane curvature directs the localization of Cdc42p to novel foci required for cell-cell fusion”, the authors explore how two mating yeast cells are able to remove their cell walls only when and where they are in contact.  They found that as the two cells come together, the region between them flattens. Remarkably, it appears that the flatness of the interface serves as a signal for a key regulatory protein, Cdc42p, to localize to the cell surface between the two cells.  Cdc42p them directs the cells walls to be removed just where the cells are in contact, allowing them to fuse.  The detection of curvature is a novel mechanism for regulating cellular events and may be conserved in higher organisms. Cdc42p is also known to play a role in the cell fusion that occurs during muscle development in mammals.

A field of mating yeast cells. On the left, Cdc42p fused to GFP (green fluorescent protein) can be seen to localize to the interface between mating yeast cells. Cdc42p-GFP is only expressed in one mating type and the yeast cells are seen at various stages of fusion.   On the right is a transmitted light image showing all the cells.