Identification of synaptic plasma membrane proteins co‐precipitated with fibrillar β‐amyloid peptide

• Published in: Journal of neurochemistry 2005-08, Vol.94 (3), p.617-628
• Main Authors: Verdier, Yann, Huszár, Emőke, Penke, Botond, Penke, Zsuzsa, Woffendin, Gary, Scigelova, Michaela, Fülöp, Lívia, Szűcs, Mária, Medzihradszky, Katalin, Janáky, Tamás
• Format: Article
• Language: English
• Subjects: Alzheimer's disease; Aminoacid receptors (glycine, glutamate, gaba); Amyloid beta-Peptides - isolation & purification; Amyloid beta-Peptides - metabolism; Animals; beta-Crystallins - metabolism; Biological and medical sciences; Brain - cytology; Brain - metabolism; Cell Membrane - metabolism; Cell Membrane - ultrastructure; Cell receptors; Cell structures and functions; Chemical Precipitation; Chromatography, High Pressure Liquid - methods; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Electrophoresis, Polyacrylamide Gel - methods; Fundamental and applied biological sciences. Psychology; Gas Chromatography-Mass Spectrometry - methods; glycolysis; Male; matrix‐assisted laser desorption/ ionization time‐of‐flight mass spectrometry; Medical sciences; Membrane Proteins - isolation & purification; Microscopy, Electron, Transmission - methods; Molecular and cellular biology; Neurofibrils - metabolism; Neurofibrils - ultrastructure; Neurology; Peptide Fragments - isolation & purification; Peptide Fragments - metabolism; Protein Binding - physiology; proteins interacting with β‐amyloid; Rats; Rats, Wistar; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization - methods; Synapses - metabolism; Synapses - ultrastructure; synaptic plasma membrane; Synaptosomes - metabolism; Synaptosomes - ultrastructure; β‐amyloid 1–42
• ISSN: 0022-3042; 1471-4159
• DOI: 10.1111/j.1471-4159.2005.03158.x

The β‐amyloid peptide that is overproduced in Alzheimer's disease rapidly forms fibrils, which are able to interact with various molecular partners. This study aimed to identify abundant synaptosomal proteins binding to the fibrillar β‐amyloid (fAβ) 1–42. Triton X‐100‐soluble proteins were extracted from the rat synaptic plasma membrane fraction. Interacting proteins were isolated by co‐precipitation with fAβ, or with fibrillar crystallin as a negative control. Protein identification was accomplished (1) by separating the tryptically digested peptides of the protein pellet by one‐dimensional reversed‐phase HPLC and analysing them using an ion‐trap mass spectrometer with electrospray ionization; and (2) by subjecting the precipitated proteins to gel electrophoretic fractionation, in‐gel tryptic digestion and to matrix‐assisted laser desorption/ionization time‐of‐flight mass measurements and post‐source decay analysis. Six different synaptosomal proteins co‐precipitated with fAβ were identified by both methods: vacuolar proton‐pump ATP synthase, glyceraldehyde‐3‐phosphate dehydrogenase, synapsins I and II, β‐tubulin and 2′,3′‐cyclic nucleotide 3′‐phosphodiesterase. Most of these proteins have already been associated with Alzheimer's disease, and the biological and pathophysiological significance of their interaction with fAβ is discussed.