Proteasomal degradation resolves competition between cell polarization and cellular wound healing.

Cellular wound healing, enabling the repair of membrane damage, is ubiquitous in eukaryotes. One aspect of the wound healing response is the redirection of a polarized cytoskeleton and the secretory machinery to the damage site. Although there has been recent progress in identifying conserved proteins involved in wound healing, the mechanisms linking these components into a coherent response are not defined. Using laser damage in budding yeast, we demonstrate that local cell wall/membrane damage triggers the dispersal of proteins from the site of polarized growth, enabling their accumulation at the wound. We define a protein-kinase-C-dependent mechanism that mediates the destruction of the formin Bni1 and the exocyst component Sec3. This degradation is essential to prevent competition between the site of polarized growth and the wound. Mechanisms to overcome competition from a pre-existing polarized cytoskeleton may be a general feature of effective wound healing in polarized cells.