title: Nucleobindin 1 binds to multiple types of pre-fibrillar amyloid and inhibits fibrillization.
abstract: During amyloid fibril formation, amyloidogenic polypeptides misfold and self assemble into soluble pre-fibrillar aggregates, i.e., protofibrils, which elongate and mature into insoluble fibrillar aggregates. An emerging class of chaperones, chaperone-like amyloid binding proteins (CLABPs), has been shown to interfere with aggregation of particular misfolded amyloid peptides or proteins. We have discovered that the calcium-binding protein nuclebindin-1 (NUCB1) is a novel CLABP. We show that NUCB1 inhibits aggregation of islet-amyloid polypeptide associated with type 2 diabetes mellitus, a-synuclein associated with Parkinson's disease, transthyretin V30M mutant associated with familial amyloid polyneuropathy, and Aβ42 associated with Alzheimer's disease by stabilizing their respective protofibril intermediates. Kinetic studies employing the modeling software AmyloFit show that NUCB1 affects both primary nucleation and secondary nucleation. We hypothesize that NUCB1 binds to the common cross-β-sheet structure of protofibril aggregates to "cap" and stabilize soluble macromolecular complexes. Transmission electron microscopy and atomic force microscopy were employed to characterize the size, shape and volume distribution of multiple sources of NUCB1-capped protofibrils. Interestingly, NUCB1 prevents Aβ42 protofibril toxicity in a cellular assay. NUCB1-stabilized amyloid protofibrils could be used as immunogens to prepare conformation-specific antibodies and as novel tools to develop screens for anti-protofibril diagnostics and therapeutics.
authors.affiliation: Laboratory of Chemical Biology &Signal Transduction, The Rockefeller University, New York, NY 10065, USA.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Bonito-Oliva
authors.affiliation: Laboratory of Chemical Biology &Signal Transduction, The Rockefeller University, New York, NY 10065, USA.
authors.forename: Shahar
authors.initials: S
authors.lastname: Barbash
authors.affiliation: Laboratory of Chemical Biology &Signal Transduction, The Rockefeller University, New York, NY 10065, USA.|Department of Neurobiology, Care Sciences and Society, Center for Alzheimer Research, Division of Neurogeriatrics, Karolinska Institutet, 141 57 Huddinge, Sweden.
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Sakmar
authors.affiliation: Laboratory of Chemical Biology &Signal Transduction, The Rockefeller University, New York, NY 10065, USA.
authors.forename: W Vallen
authors.initials: WV
authors.lastname: Graham
mesh_terms: D000682:Amyloid / Q000737:chemistry / Q000378:metabolism*; D016229:Amyloid beta-Peptides / Q000737:chemistry / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism / Q000473:pathology; D006801:Humans; D058228:Islet Amyloid Polypeptide / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D018625:Microscopy, Atomic Force; D016297:Mutagenesis, Site-Directed; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000080866:Nucleobindins; D010300:Parkinson Disease / Q000378:metabolism / Q000473:pathology; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism*; D011228:Prealbumin / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D017433:Protein Structure, Secondary; D051844:alpha-Synuclein / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000682:Amyloid; D016229:Amyloid beta-Peptides; D002135:Calcium-Binding Proteins; D004268:DNA-Binding Proteins; D058228:Islet Amyloid Polypeptide; C000630649:NUCB1 protein, human; D009419:Nerve Tissue Proteins; D000080866:Nucleobindins; D010446:Peptide Fragments; D011228:Prealbumin; D051844:alpha-Synuclein; C075222:amyloid beta-protein (1-42); C041120:amyloid prealbumin