Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
16
pubmed:dateCreated
2008-9-22
pubmed:abstractText
Cellular repressor of E1A-stimulated genes (CREG) has been reported to be a secretory glycoprotein implicated in cellular growth and differentiation. We now show that CREG is predominantly localized within intracellular compartments. Intracellular CREG was found to lack an N-terminal peptide present in the secreted form of the protein. In contrast to normal cells, CREG is largely secreted by fibroblasts missing both mannose 6-phosphate receptors. This is not observed in cells lacking only one of them. Mass spectrometric analysis of recombinant CREG revealed that the protein contains phosphorylated oligosaccharides at either of its two N-glycosylation sites. Cellular CREG was found to cosediment with lysosomal markers upon subcellular fractionation by density-gradient centrifugation. In fibroblasts expressing a CREG-GFP fusion construct, the heterologous protein was detected in compartments containing lysosomal proteins. Immunolocalization of endogenous CREG confirmed that intracellular CREG is localized in lysosomes. Proteolytic processing of intracellular CREG involves the action of lysosomal cysteine proteinases. These results establish that CREG is a lysosomal protein that undergoes proteolytic maturation in the course of its biosynthesis, carries the mannose 6-phosphate recognition marker and depends on the interaction with mannose 6-phosphate receptors for efficient delivery to lysosomes.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
1090-2422
pubmed:author
pubmed:issnType
Electronic
pubmed:day
1
pubmed:volume
314
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3036-47
pubmed:meshHeading
pubmed-meshheading:18621046-Animals, pubmed-meshheading:18621046-COS Cells, pubmed-meshheading:18621046-Cercopithecus aethiops, pubmed-meshheading:18621046-Cysteine Endopeptidases, pubmed-meshheading:18621046-Glycosylation, pubmed-meshheading:18621046-Humans, pubmed-meshheading:18621046-Insects, pubmed-meshheading:18621046-Lysosomes, pubmed-meshheading:18621046-Mannosephosphates, pubmed-meshheading:18621046-Mass Spectrometry, pubmed-meshheading:18621046-Mice, pubmed-meshheading:18621046-Oligosaccharides, pubmed-meshheading:18621046-Peptides, pubmed-meshheading:18621046-Protease Inhibitors, pubmed-meshheading:18621046-Protein Processing, Post-Translational, pubmed-meshheading:18621046-Receptor, IGF Type 2, pubmed-meshheading:18621046-Recombinant Fusion Proteins, pubmed-meshheading:18621046-Repressor Proteins
pubmed:year
2008
pubmed:articleTitle
Cellular repressor of E1A-stimulated genes is a bona fide lysosomal protein which undergoes proteolytic maturation during its biosynthesis.
pubmed:affiliation
Institut für Angewandte Genetik und Zellbiologie, Universität für Bodenkultur Wien, Muthgasse 18, A-1190 Vienna, Austria.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't