Members of the aegerolysins protein family are unique in their binding to specific lipids and lipid membrane domains. They can be used as specific membrane markers, or as tools for targeting specific cell types. Ostreolysin A (OlyA) is an aegerolysin from the edible oyster mushroom Pleurotus ostreatus. OlyA was shown to bind to biological and artificial lipid membranes enriched with sphingomyelin and cholesterol. Recently discovered erylysin A (EryA) from the mushroom Pleurotus eryngii specifically binds to ceramide phosphoethanolamine (CPE), a sphingolipid found in higher quantities in cell membranes of insects, some parasites and bacteria. We tested the lipid-binding activity of recombinant fluorescently-labelled aegerolysins OlyA-eGFP and EryA-mCherry to oral mucose cells. We found that OlyA-eGFP binds to plasma membrane of oral mucose cells, but the binding of EryA-mCherry on plasma membrane of oral mucose cells, which do not contain CPE, was not shown. We tested the binding specifity of OlyA-eGFP in EryA-mCherry on in-vitro culture of non-differntiated neurons, whose plasma membrane is enriched with sphingomyelin and cholesterol, and also contain trace amount of CPE. We found that OlyA-eGFP binds on plasma membrane of these cells and therefore could be used as a specific membrane marker for membrane rafts in neural cells. The binding of EryA-mCherry on non-differntiated neurons was not detected – probably because of too low amount of CPE in their plasma membranes - and thus EryA could not be used as specific membrane marker for CPE in these cells.
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