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).
References:
Anderluh, G. and E. Zerovnik. (2012). Pore formation by human stefin B in its native and oligomeric states and the consequent amyloid induced toxicity. Front Mol Neurosci 5: 85.
Rabzelj, S., G. Viero, I. Gutiérrez-Aguirre, V. Turk, M. Dalla Serra, G. Anderluh, and E. Zerovnik. (2008). Interaction with model membranes and pore formation by human stefin B: studying the native and prefibrillar states. FEBS J. 275: 2455-2466.
Examples:
TC#	Name	Organismal Type	Example
1.C.91.1.1	The tetrameric Stefin B pore-forming protein (98aas); structure known (20CT_A)	Metazoa	*Stefin B of Homo sapiens* (P04080)**