Ostreolysin, a Cytolytic Protein from Culinary-Medicinal Oyster Mushroom Pleurotus ostreatus (Jacq.: Fr.) P. Kumm. (Agaricomycetideae), and Its Potential Use in Medicine and Biotechnology

摘要

Ostreolysin is a 15-kDa cytolytic protein from the edible oyster mushroom Pleurotus ostreatus. It belongs to the aegerolysin family of small acidic proteins found in bacteria, fungi, and plants, but its biological role is not known. However, its appearance at the stage of primordial formation and its occurrence in peripheral parts of the fruiting bodies and lamellae suggest an involvement in the process of differentiation of hyphae and formation of basidia and spores of the mushroom. Its ability to induce fructification and enhance the yield of young oyster mushrooms after external application to the mushroom mycelium suggests that ostreolysin could be applied in biotechnological processes associated with mushroom farming. This protein is also able to induce the formation of transmembrane pores in natural and artificial lipid membranes. The process of cell lysis results from the specific interaction of ostreolysin with cholesterol-enriched raft-like membrane domains, which, however, differ from those binding caveolin or cholera toxin subunit B. Immunolocalization studies suggest that nontoxic mutants of ostreolysin could be used as specific markers for cholesterol-rich raft-like membrane domains and for studies of lipid raft heterogeneity.