Molecular cloning of cDNA encoding an unrecognized component of amyloid in Alzheimer disease.

Abstract

A neuropathological hallmark of Alzheimer disease (AD) is a widespread amyloid deposition. We analyzed the entire amino acid sequences in an amyloid preparation and found, in addition to the major I3/A4-protein (AP) fragment, two unknown peptides. We raised antibodies against synthetic peptides using subsequences ofthese peptides. These antibodies immunostained amyloid in neuritic and diffuse plaques as well as vascular amyloid. Electron microscopic analysis demonstrated that the immunostaining was localized on amyloid fibrils. We have isolated an apparently full-length cDNA encoding a 140-amino-acid protein within which two previously unreported amyloid sequences are encoded in tandem in the most hydrophobic domain. We tentatively named this 35-amino acid peptide NAC (non-A(8 component of AD amyloid) and its precursor NACP. NAC is the second component, after A.8, identified chemically in the purified AD amyloid preparation. Secondary structure predictions indicate that the NAC peptide sequence has a strong tendency to form (structures consistent with its association with amyloid. NACP is detected as a M, 19,000 protein in the cytosolic fraction of brain homogenates and comigrates on immunoblots with NACP synthesized in Escherichia coli from NACP cDNA. NACP mRNA is expressed principally in brain but is also expressed in low concentrations in all tissues examined except in liver, suggesting its ubiquitous and brain-specific functions. The availability of the cDNA encoding full-length NACP should help to elucidate the mechanisms of amyloidosis in AD.Amyloid deposition in the neuritic plaque and blood vessels is the most consistent neuropathology in Alzheimer disease (AD) (1, 2). The major constituent of amyloid has been found to be a 39-to 43-amino acid amyloid 13/A4-protein (AP3) (3,4) derived from its precursor, APP (5-8). The isolation of APP cDNA prompted a burst-of research in AD, culminating in the identification of APP mutations in several familial types of AD (9-12). Thus, APP and AP have been proposed to play a key role in the pathogenesis of this disease (13, 14). Additionally, heparan sulfate proteoglycan, ferritin, immunoglobulins, and many acute-phase proteins, such as a1-antichymotrypsin (ACT), apolipoprotein E, complements, serum amyloid P, and trace peptides were also reported to be associated with plaque core amyloid (15-29), although supportive biochemical data demonstrating their presence in amyloid preparations are not yet available, raising the possibility that those might not be the intrinsic components of amyloid. We have further pursued the biochemical examination of the intrinsic constituents of AD amyloid by purification in SDS and sequencing, and we detected a previouslyThe publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.unrecognized component that we tentatively call NAC (non-AP component of AD amyloid) in this communication...

Alpha-synuclein deficiency and efferent nerve degeneration in the mouse cochlea: A possible cause of early-onset presbycusis

“…All rights reserved. doi:10.1016/j.neures.2011.07.1835 (Ueda et al, 1993;Ueda and Mori, 1994). The co-localization of ␣-synuclein and synaptophysin during neural development indicates the spatially regulated functions of these proteins, perhaps related to synaptic specialization or complementary roles in regulating presynaptic elements (Murphy et al, 2000).…”

19F NMR studies of α‐synuclein‐membrane interactions

“…1) is a 140 amino-acid, intrinsically-disordered protein associated with Parkinson's disease and other neurodegenerative disorders [1][2][3][4][5][6][7][8] whose function is hypothesized to involve its interaction with membranes. [8][9][10][11][12] The protein binds lipids and anionic detergents through the seven imperfect, cationic, 11-amino acid repeats located in its N-terminal and hydrophobic regions.…”

The 5′-untranslated region of Parkinson's disease α-synuclein messengerRNA contains a predicted iron responsive element

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