Interaction with model membranes and pore formation by human stefin B: studying the native and prefibrillar states.
Human stefin B, from the family of cystatins, is used as a model amyloidogenic protein in studies of the mechanism of amyloid fibril formation and related cytotoxicity. Interaction of the protein's prefibrillar oligomers/aggregates with predominantly acidic phospholipid membranes is known to correlate with cellular toxicity. In the present study, we measured membrane interaction of the prefibrillar and native states for three variants: the Y31 isoform studied previously, the wild-type protein and the G4R mutant; the latter is observed in progressive myoclonus epilepsy of type 1. In addition to using critical pressure and surface plasmon resonance, we assessed membrane permeabilization by calcein release and electrophysiological measurements. It was demonstrated for the first time that 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 and the possible physiological implications of our findings are discussed.
Rabzelj
Sabina
S
Department of Biochemistry and Molecular Biology, JoZef Stefan Institute, Ljubljana, Slovenia.
Viero
Gabriella
G
Gutiérrez-Aguirre
Ion
I
Turk
Vito
V
Dalla Serra
Mauro
M
Anderluh
Gregor
G
Zerovnik
Eva
E
D000682:Amyloid / Q000737:chemistry / Q000378:metabolism; D055313:Cystatin B; D015891:Cystatins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D015853:Cysteine Proteinase Inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004594:Electrophysiology; D006801:Humans; D008081:Liposomes / Q000737:chemistry / Q000378:metabolism; D008563:Membrane Lipids / Q000737:chemistry / Q000378:metabolism; D008566:Membranes / Q000737:chemistry / Q000378:metabolism; D008954:Models, Biological; D011487:Protein Conformation; D017510:Protein Folding; D020033:Protein Isoforms / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020349:Surface Plasmon Resonance
D000682:Amyloid; C524994:CSTB protein, human; D015891:Cystatins; D015853:Cysteine Proteinase Inhibitors; D008081:Liposomes; D008563:Membrane Lipids; D020033:Protein Isoforms; D011994:Recombinant Proteins; D055313:Cystatin B