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c-Cbl binding and ubiquitin-dependent lysosomal degradation of membrane-associated Notch1
Author(s): Jehn BM, Dittert I, Beyer S, von der Mark K, Bielke W
Source: JOURNAL OF BIOLOGICAL CHEMISTRY    Volume: 277    Issue: 10    Pages: 8033-8040    Published: MAR 8 2002  
Times Cited: 50     References: 38     
Abstract: Regulation of Notch1 activity is critical for cell fate decisions and differentiation of skeletal myoblasts. We have employed the skeletal myoblast cell line C2C12 to study posttranslational regulation of Notch1 protein levels during myogenesis. Although the major degradation pathway of the activated intracellular Notch1 fragment appears to involve ubiquitination and degradation by the 26 S proteasome, we provide evidence for an alternative catalytic pathway where the endogenous, transmembrane form of Notch1 is targeted to the lysosomal compartment. Immunoprecipitation analysis revealed ubiquitin-dependent accumulation of transmembrane Notch1 protein after treatment with the lysosomal inhibitor chloroquine but not after treatment with various proteasome inhibitors. This finding was supported by the observation that the transmembrane form of Notch1 was tyrosine-phosphorylated and specifically coprecipitated with the ubiquitin ligase c-Cbl. Our data suggest a regulatory mechanism down-regulating Notch1 protein levels already at the cellular surface, possibly with consequences for Notch-dependent signal transduction during terminal differentiation processes.
Document Type: Article
Language: English
Reprint Address: Bielke, W (reprint author), Univ Erlangen Nurnberg, Dept Expt Med 1, Nikolaus Fiebiger Zentrum, Gluckstr 6, D-91054 Erlangen, Germany
Addresses:
1. Univ Erlangen Nurnberg, Dept Expt Med 1, Nikolaus Fiebiger Zentrum, D-91054 Erlangen, Germany
2. Univ Erlangen Nurnberg, Div Mol Immunol, Dept Internal Med 3, D-91054 Erlangen, Germany
Publisher: AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC, 9650 ROCKVILLE PIKE, BETHESDA, MD 20814-3996 USA
Subject Category: Biochemistry & Molecular Biology
IDS Number: 528WR
ISSN: 0021-9258
DOI: 10.1074/jbc.M108552200
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