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Generation and regulation of β-amyloid peptide variants by neurons

Gouras, Gunnar K. LU ; Xu, Huaxi ; Jovanovic, Jasmina N. ; Buxbaum, Joseph D. ; Wang, Rong ; Greengard, Paul ; Relkin, Norman R. and Gandy, Sam (1998) In Journal of Neurochemistry 71(5). p.1920-1925
Abstract

Studies of processing of the Alzheimer β-amyloid precursor protein (βAPP) have been performed to date mostly in continuous cell lines and indicate the existence of two principal metabolic pathways: the 'β- secretase' pathway, which generates β-amyloid (Aβ(1-40/42); ~4 kDa), and the 'α-secretase' pathway, which generates a smaller fragment, the 'p3' peptide (Aβ(17-40/42); ~3 kDa). To determine whether similar processing events underlie βAPP metabolism in neurons, media were examined following conditioning by primary neuronal cultures derived from embryonic day 17 rats. Immunoprecipitates of conditioned media derived from [35S]methionine pulse- labeled primary neuronal cultures contained 4- and 3-kDa Aβ-related species.... (More)

Studies of processing of the Alzheimer β-amyloid precursor protein (βAPP) have been performed to date mostly in continuous cell lines and indicate the existence of two principal metabolic pathways: the 'β- secretase' pathway, which generates β-amyloid (Aβ(1-40/42); ~4 kDa), and the 'α-secretase' pathway, which generates a smaller fragment, the 'p3' peptide (Aβ(17-40/42); ~3 kDa). To determine whether similar processing events underlie βAPP metabolism in neurons, media were examined following conditioning by primary neuronal cultures derived from embryonic day 17 rats. Immunoprecipitates of conditioned media derived from [35S]methionine pulse- labeled primary neuronal cultures contained 4- and 3-kDa Aβ-related species. Radiosequencing analysis revealed that the 4-kDa band corresponded to conventional Aβ beginning at position Aβ(Asp1), whereas both radio- sequencing and immunoprecipitation-mass spectrometry analyses indicated that the 3-kDa species in these conditioned media began with Aβ(Glu11) at the N terminus, rather than Aβ(Leu17) as does the conventional p3 peptide. Either activation of protein kinase C or inhibition of protein phosphatase 1/2A increased soluble βAPP(α) release and decreased generation of both the 4-kDa Aβ and the 3-kDa N-truncated Aβ. Unlike results obtained with continuously cultured cells, protein phosphatase 1/2A inhibitors were more potent at reducing Aβ secretion by neurons than were protein kinase C activators. These data indicate that rodent neurons generate abundant Aft variant peptides and emphasize the role of protein phosphatases in modulating neuronal Aβ generation.

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author
publishing date
type
Contribution to journal
publication status
published
subject
keywords
β-Amyloid peptides, Alzheimer's disease, Amyloid precursor protein, Neurons, Protein kinase, Protein phosphatase
in
Journal of Neurochemistry
volume
71
issue
5
pages
1920 - 1925
publisher
Wiley-Blackwell
external identifiers
  • pmid:9798916
  • scopus:0031784101
ISSN
0022-3042
DOI
10.1046/j.1471-4159.1998.71051920.x
language
English
LU publication?
no
id
f033bb7f-505a-4fdf-a937-53b8718398c0
date added to LUP
2020-02-20 14:29:39
date last changed
2020-05-24 06:30:08
@article{f033bb7f-505a-4fdf-a937-53b8718398c0,
  abstract     = {<p>Studies of processing of the Alzheimer β-amyloid precursor protein (βAPP) have been performed to date mostly in continuous cell lines and indicate the existence of two principal metabolic pathways: the 'β- secretase' pathway, which generates β-amyloid (Aβ(1-40/42); ~4 kDa), and the 'α-secretase' pathway, which generates a smaller fragment, the 'p3' peptide (Aβ(17-40/42); ~3 kDa). To determine whether similar processing events underlie βAPP metabolism in neurons, media were examined following conditioning by primary neuronal cultures derived from embryonic day 17 rats. Immunoprecipitates of conditioned media derived from [<sup>35</sup>S]methionine pulse- labeled primary neuronal cultures contained 4- and 3-kDa Aβ-related species. Radiosequencing analysis revealed that the 4-kDa band corresponded to conventional Aβ beginning at position Aβ(Asp<sup>1</sup>), whereas both radio- sequencing and immunoprecipitation-mass spectrometry analyses indicated that the 3-kDa species in these conditioned media began with Aβ(Glu<sup>11</sup>) at the N terminus, rather than Aβ(Leu<sup>17</sup>) as does the conventional p3 peptide. Either activation of protein kinase C or inhibition of protein phosphatase 1/2A increased soluble βAPP(α) release and decreased generation of both the 4-kDa Aβ and the 3-kDa N-truncated Aβ. Unlike results obtained with continuously cultured cells, protein phosphatase 1/2A inhibitors were more potent at reducing Aβ secretion by neurons than were protein kinase C activators. These data indicate that rodent neurons generate abundant Aft variant peptides and emphasize the role of protein phosphatases in modulating neuronal Aβ generation.</p>},
  author       = {Gouras, Gunnar K. and Xu, Huaxi and Jovanovic, Jasmina N. and Buxbaum, Joseph D. and Wang, Rong and Greengard, Paul and Relkin, Norman R. and Gandy, Sam},
  issn         = {0022-3042},
  language     = {eng},
  month        = {11},
  number       = {5},
  pages        = {1920--1925},
  publisher    = {Wiley-Blackwell},
  series       = {Journal of Neurochemistry},
  title        = {Generation and regulation of β-amyloid peptide variants by neurons},
  url          = {http://dx.doi.org/10.1046/j.1471-4159.1998.71051920.x},
  doi          = {10.1046/j.1471-4159.1998.71051920.x},
  volume       = {71},
  year         = {1998},
}