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Regulated Intramembrane Proteolysis and Degradation of Murine Epithelial Cell Adhesion Molecule mEpCAM
Epithelial cell adhesion molecule EpCAM is a transmembrane glycoprotein, which is highly and frequently expressed in carcinomas and (cancer-)stem cells, and which plays an important role in the regulation of stem cell pluripotency. We show here that murine EpCAM (mEpCAM) is subject to regulated intr...
Autores principales: | , , , , , , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2013
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3756971/ https://www.ncbi.nlm.nih.gov/pubmed/24009667 http://dx.doi.org/10.1371/journal.pone.0071836 |
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author | Hachmeister, Matthias Bobowski, Karolina D. Hogl, Sebastian Dislich, Bastian Fukumori, Akio Eggert, Carola Mack, Brigitte Kremling, Heidi Sarrach, Sannia Coscia, Fabian Zimmermann, Wolfgang Steiner, Harald Lichtenthaler, Stefan F. Gires, Olivier |
author_facet | Hachmeister, Matthias Bobowski, Karolina D. Hogl, Sebastian Dislich, Bastian Fukumori, Akio Eggert, Carola Mack, Brigitte Kremling, Heidi Sarrach, Sannia Coscia, Fabian Zimmermann, Wolfgang Steiner, Harald Lichtenthaler, Stefan F. Gires, Olivier |
author_sort | Hachmeister, Matthias |
collection | PubMed |
description | Epithelial cell adhesion molecule EpCAM is a transmembrane glycoprotein, which is highly and frequently expressed in carcinomas and (cancer-)stem cells, and which plays an important role in the regulation of stem cell pluripotency. We show here that murine EpCAM (mEpCAM) is subject to regulated intramembrane proteolysis in various cells including embryonic stem cells and teratocarcinomas. As shown with ectopically expressed EpCAM variants, cleavages occur at α-, β-, γ-, and ε-sites to generate soluble ectodomains, soluble Aβ-like-, and intracellular fragments termed mEpEX, mEp-β, and mEpICD, respectively. Proteolytic sites in the extracellular part of mEpCAM were mapped using mass spectrometry and represent cleavages at the α- and β-sites by metalloproteases and the b-secretase BACE1, respectively. Resulting C-terminal fragments (CTF) are further processed to soluble Aβ-like fragments mEp-β and cytoplasmic mEpICD variants by the g-secretase complex. Noteworthy, cytoplasmic mEpICD fragments were subject to efficient degradation in a proteasome-dependent manner. In addition the γ-secretase complex dependent cleavage of EpCAM CTF liberates different EpICDs with different stabilities towards proteasomal degradation. Generation of CTF and EpICD fragments and the degradation of hEpICD via the proteasome were similarly demonstrated for the human EpCAM ortholog. Additional EpCAM orthologs have been unequivocally identified in silico in 52 species. Sequence comparisons across species disclosed highest homology of BACE1 cleavage sites and in presenilin-dependent γ-cleavage sites, whereas strongest heterogeneity was observed in metalloprotease cleavage sites. In summary, EpCAM is a highly conserved protein present in fishes, amphibians, reptiles, birds, marsupials, and placental mammals, and is subject to shedding, γ-secretase-dependent regulated intramembrane proteolysis, and proteasome-mediated degradation. |
format | Online Article Text |
id | pubmed-3756971 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2013 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-37569712013-09-05 Regulated Intramembrane Proteolysis and Degradation of Murine Epithelial Cell Adhesion Molecule mEpCAM Hachmeister, Matthias Bobowski, Karolina D. Hogl, Sebastian Dislich, Bastian Fukumori, Akio Eggert, Carola Mack, Brigitte Kremling, Heidi Sarrach, Sannia Coscia, Fabian Zimmermann, Wolfgang Steiner, Harald Lichtenthaler, Stefan F. Gires, Olivier PLoS One Research Article Epithelial cell adhesion molecule EpCAM is a transmembrane glycoprotein, which is highly and frequently expressed in carcinomas and (cancer-)stem cells, and which plays an important role in the regulation of stem cell pluripotency. We show here that murine EpCAM (mEpCAM) is subject to regulated intramembrane proteolysis in various cells including embryonic stem cells and teratocarcinomas. As shown with ectopically expressed EpCAM variants, cleavages occur at α-, β-, γ-, and ε-sites to generate soluble ectodomains, soluble Aβ-like-, and intracellular fragments termed mEpEX, mEp-β, and mEpICD, respectively. Proteolytic sites in the extracellular part of mEpCAM were mapped using mass spectrometry and represent cleavages at the α- and β-sites by metalloproteases and the b-secretase BACE1, respectively. Resulting C-terminal fragments (CTF) are further processed to soluble Aβ-like fragments mEp-β and cytoplasmic mEpICD variants by the g-secretase complex. Noteworthy, cytoplasmic mEpICD fragments were subject to efficient degradation in a proteasome-dependent manner. In addition the γ-secretase complex dependent cleavage of EpCAM CTF liberates different EpICDs with different stabilities towards proteasomal degradation. Generation of CTF and EpICD fragments and the degradation of hEpICD via the proteasome were similarly demonstrated for the human EpCAM ortholog. Additional EpCAM orthologs have been unequivocally identified in silico in 52 species. Sequence comparisons across species disclosed highest homology of BACE1 cleavage sites and in presenilin-dependent γ-cleavage sites, whereas strongest heterogeneity was observed in metalloprotease cleavage sites. In summary, EpCAM is a highly conserved protein present in fishes, amphibians, reptiles, birds, marsupials, and placental mammals, and is subject to shedding, γ-secretase-dependent regulated intramembrane proteolysis, and proteasome-mediated degradation. Public Library of Science 2013-08-29 /pmc/articles/PMC3756971/ /pubmed/24009667 http://dx.doi.org/10.1371/journal.pone.0071836 Text en © 2013 Hachmeister et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited. |
spellingShingle | Research Article Hachmeister, Matthias Bobowski, Karolina D. Hogl, Sebastian Dislich, Bastian Fukumori, Akio Eggert, Carola Mack, Brigitte Kremling, Heidi Sarrach, Sannia Coscia, Fabian Zimmermann, Wolfgang Steiner, Harald Lichtenthaler, Stefan F. Gires, Olivier Regulated Intramembrane Proteolysis and Degradation of Murine Epithelial Cell Adhesion Molecule mEpCAM |
title | Regulated Intramembrane Proteolysis and Degradation of Murine Epithelial Cell Adhesion Molecule mEpCAM |
title_full | Regulated Intramembrane Proteolysis and Degradation of Murine Epithelial Cell Adhesion Molecule mEpCAM |
title_fullStr | Regulated Intramembrane Proteolysis and Degradation of Murine Epithelial Cell Adhesion Molecule mEpCAM |
title_full_unstemmed | Regulated Intramembrane Proteolysis and Degradation of Murine Epithelial Cell Adhesion Molecule mEpCAM |
title_short | Regulated Intramembrane Proteolysis and Degradation of Murine Epithelial Cell Adhesion Molecule mEpCAM |
title_sort | regulated intramembrane proteolysis and degradation of murine epithelial cell adhesion molecule mepcam |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3756971/ https://www.ncbi.nlm.nih.gov/pubmed/24009667 http://dx.doi.org/10.1371/journal.pone.0071836 |
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