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APP/APLP2 expression is required to initiate endosome-nucleus-autophagosome trafficking of glypican-1-derived heparan sulfate.

Cheng, Fang LU ; Cappai, Roberto; Lidfeldt, Jon LU ; Belting, Mattias LU ; Fransson, Lars-Åke LU and Mani, Katrin LU (2014) In Journal of Biological Chemistry 289(30). p.20871-20878
Abstract
Anhydromannose (anMan)-containing heparan sulfate (HS) derived from the proteoglycan glypican-1 (Gpc-1) is generated in endosomes by an endogenously or ascorbate induced SNO-catalyzed reaction. Processing of the amyloid precursor protein (APP) and APP-like protein 2 (APLP2) by β- and γ-secretases into amyloid beta (Aβ) and Aβ-like peptides also takes place in these compartments. Moreover, anMan-containing HS suppresses the formation of toxic Aβ assemblies in vitro. We show by using deconvolution immunofluorescence microscopy with an anMan-specific monoclonal antibody as well as 35S-labeling experiment that expression of APP/APLP2 is required for ascorbate-induced transport of HS from endosomes to the nucleus. Nuclear translocation was... (More)
Anhydromannose (anMan)-containing heparan sulfate (HS) derived from the proteoglycan glypican-1 (Gpc-1) is generated in endosomes by an endogenously or ascorbate induced SNO-catalyzed reaction. Processing of the amyloid precursor protein (APP) and APP-like protein 2 (APLP2) by β- and γ-secretases into amyloid beta (Aβ) and Aβ-like peptides also takes place in these compartments. Moreover, anMan-containing HS suppresses the formation of toxic Aβ assemblies in vitro. We show by using deconvolution immunofluorescence microscopy with an anMan-specific monoclonal antibody as well as 35S-labeling experiment that expression of APP/APLP2 is required for ascorbate-induced transport of HS from endosomes to the nucleus. Nuclear translocation was observed in wild-type mouse embryonic fibroblasts (Wt-MEF), Tg2576 MEF and N2a neuroblastoma cells but not in APP-/- and APLP2-/- MEF. Transfection of APP-/- cells with a vector encoding APP restored nuclear import of anMan-containing HS. In Wt-MEF and N2a neuroblastoma cells exposed to β- or γ-secretase inhibitors, nuclear translocation was greatly impeded, suggesting involvement of APP/APLP2 degradation products. In Tg2576 MEF, the β-inhibitor blocked transport but the γ- inhibitor did not. During chase in ascorbate-free medium, anMan-containing HS disappeared from the nuclei of Wt-MEF. Confocal immunofluorescence microscopy showed that they appeared in acidic, LC3-positive vesicles in keeping with an autophagosomal location. There was increased accumulation of anMan-containing HS in nuclei and cytosolic vesicles upon treatment with chloroquine indicating that HS was degraded in lysosomes. Manipulations of APP expression and processing may have deleterious effects upon HS function in the nucleus. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Biological Chemistry
volume
289
issue
30
pages
20871 - 20878
publisher
ASBMB
external identifiers
  • pmid:24898256
  • wos:000339396600041
  • scopus:84905373399
ISSN
1083-351X
DOI
10.1074/jbc.M114.552810
language
English
LU publication?
yes
id
5e9f034a-cec7-49bd-bc80-9c4bd74bb2bb (old id 4529242)
alternative location
http://www.ncbi.nlm.nih.gov/pubmed/24898256?dopt=Abstract
date added to LUP
2014-07-04 15:22:19
date last changed
2017-07-23 03:24:04
@article{5e9f034a-cec7-49bd-bc80-9c4bd74bb2bb,
  abstract     = {Anhydromannose (anMan)-containing heparan sulfate (HS) derived from the proteoglycan glypican-1 (Gpc-1) is generated in endosomes by an endogenously or ascorbate induced SNO-catalyzed reaction. Processing of the amyloid precursor protein (APP) and APP-like protein 2 (APLP2) by β- and γ-secretases into amyloid beta (Aβ) and Aβ-like peptides also takes place in these compartments. Moreover, anMan-containing HS suppresses the formation of toxic Aβ assemblies in vitro. We show by using deconvolution immunofluorescence microscopy with an anMan-specific monoclonal antibody as well as 35S-labeling experiment that expression of APP/APLP2 is required for ascorbate-induced transport of HS from endosomes to the nucleus. Nuclear translocation was observed in wild-type mouse embryonic fibroblasts (Wt-MEF), Tg2576 MEF and N2a neuroblastoma cells but not in APP-/- and APLP2-/- MEF. Transfection of APP-/- cells with a vector encoding APP restored nuclear import of anMan-containing HS. In Wt-MEF and N2a neuroblastoma cells exposed to β- or γ-secretase inhibitors, nuclear translocation was greatly impeded, suggesting involvement of APP/APLP2 degradation products. In Tg2576 MEF, the β-inhibitor blocked transport but the γ- inhibitor did not. During chase in ascorbate-free medium, anMan-containing HS disappeared from the nuclei of Wt-MEF. Confocal immunofluorescence microscopy showed that they appeared in acidic, LC3-positive vesicles in keeping with an autophagosomal location. There was increased accumulation of anMan-containing HS in nuclei and cytosolic vesicles upon treatment with chloroquine indicating that HS was degraded in lysosomes. Manipulations of APP expression and processing may have deleterious effects upon HS function in the nucleus.},
  author       = {Cheng, Fang and Cappai, Roberto and Lidfeldt, Jon and Belting, Mattias and Fransson, Lars-Åke and Mani, Katrin},
  issn         = {1083-351X},
  language     = {eng},
  number       = {30},
  pages        = {20871--20878},
  publisher    = {ASBMB},
  series       = {Journal of Biological Chemistry},
  title        = {APP/APLP2 expression is required to initiate endosome-nucleus-autophagosome trafficking of glypican-1-derived heparan sulfate.},
  url          = {http://dx.doi.org/10.1074/jbc.M114.552810},
  volume       = {289},
  year         = {2014},
}