Self-incompatibility (SI) is generally controlled by the S-locus, and comprises allelic pollen and pistil S-determinants. Poulter et al. review and discuss our current understanding of the cytoskeletal alterations induced in incompatible pollen during SI and their relationship with programmed cell death in Papaver rhoeas, focussing on data relating to the formation of F-actin punctate foci. Analysis has identified differences between proteins associated with F-actin from SI-induced pollen samples and those associated with F-actin in untreated pollen. This provides candidate proteins implicated in either the formation or stabilization of the punctate actin structures formed during SI.