EditoriaL EditoriaL

The endoplasmic reticulum (ER) forms an elaborate membra-nous network that functions as the major processing center for the folding and assembly of secreted and membrane proteins. Sev-eral environmental conditions can overwhelm the protein folding capacity of the ER, resulting in the accumulation of unfolded proteins. Since unfolded proteins can seed the formation of pro-tein aggregates that are toxic to cells, their accumulation is tightly linked to the activation of stress response pathways that restore protein folding homeostasis.1 In this special focus of Virulence we highlight recent advances in fungal biology that demonstrate the interplay between ER stress responses and virulence in four spe-cies of pathogenic fungi (two molds and two yeasts). Despite the fact that these organisms have very different lifestyles, and deploy unique species-specific virulence factors during infection, they all share the common characteristic of relying upon ER stres