Interaction between oligomers of stefin B and amyloid-beta in vitro and in cells.
To contribute to the question of the putative role of cystatins in Alzheimer disease and in neuroprotection in general, we studied the interaction between human stefin B (cystatin B) and amyloid-beta-(1-40) peptide (Abeta). Using surface plasmon resonance and electrospray mass spectrometry we were able to show a direct interaction between the two proteins. As an interesting new fact, we show that stefin B binding to Abeta is oligomer specific. The dimers and tetramers of stefin B, which bind Abeta, are domain-swapped as judged from structural studies. Consistent with the binding results, the same oligomers of stefin B inhibit Abeta fibril formation. When expressed in cultured cells, stefin B co-localizes with Abeta intracellular inclusions. It also co-immunoprecipitates with the APP fragment containing the Abeta epitope. Thus, stefin B is another APP/Abeta-binding protein in vitro and likely in cells.
Skerget
Katja
K
Department of Biochemistry, Molecular and Structural Biology, JoZef Stefan Institute, Jamova 39, Slovenia.
Taler-Vercic
Ajda
A
Bavdek
Andrej
A
Hodnik
Vesna
V
Ceru
Slavko
S
Tusek-Znidaric
Magda
M
Kumm
Tiina
T
Pitsi
Didier
D
Pompe-Novak
Marusa
M
Palumaa
Peep
P
Soriano
Salvador
S
Kopitar-Jerala
Natasa
N
Turk
Vito
V
Anderluh
Gregor
G
Zerovnik
Eva
E
D016229:Amyloid beta-Peptides / Q000737:chemistry*; D000818:Animals; D052160:Benzothiazoles; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D055313:Cystatin B / Q000737:chemistry*; D019281:Dimerization; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000737:chemistry; D006801:Humans; D066298:In Vitro Techniques; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence / Q000379:methods; D011485:Protein Binding; D021241:Spectrometry, Mass, Electrospray Ionization; D020349:Surface Plasmon Resonance; D013844:Thiazoles / Q000737:chemistry
D016229:Amyloid beta-Peptides; D052160:Benzothiazoles; D000939:Epitopes; D013844:Thiazoles; C009462:thioflavin T; D055313:Cystatin B