1.C.91 The Stefin B Pore-forming Protein (Stefin B) Family

Human stefin B, from the family of cystatins, is a model amyloidogenic protein to study the mechanism of amyloid fibril formation and cytotoxicity. Interaction of the protein's prefibrillar oligomers/aggregates with predominantly acidic phospholipid membranes is known to correlate with cellular toxicity.  Rabzelj et al. (2008) studied membrane interaction of the prefibrillar and native states for three variants: Y31 isoform, the wild-type protein and the G4R mutant.  The G4R mutant is observed in progressive myoclonus epilepsy type 1. Wild-type stefin B and the Y31 isoform are able to form pores in planar lipid bilayers, whereas G4R destroys the bilayer by a non pore-forming process. Similarities to other amyloidogenic proteins have been considered (Rabzelj et al., 2008).