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Endocytosis and degradation of the growth hormone receptor are proteasome-dependent.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 2000 Jan 21; Vol. 275 (3), pp. 1575-80. - Publication Year :
- 2000
-
Abstract
- The ubiquitin conjugation system is involved in ligand-induced endocytosis of the growth hormone receptor (GHR) via a cytosolic 10-amino acid ubiquitin-dependent endocytosis motif. Herein, we demonstrate that the proteasome is also involved in growth hormone receptor down-regulation. Ligand-induced degradation was blocked in the presence of specific proteasomal inhibitors. In addition, growth hormone (GH) internalization was inhibited, whereas the transferrin receptor cycle remained unaffected. A truncated GHR entered the cells independent of proteasome action. In addition, we show that GH internalization is independent of the presence of lysine residues in the cytosolic domain of the receptor, whereas its internalization can still be inhibited by proteasomal inhibitors. Thus, GHR internalization requires proteasome action in addition to an active ubiquitin conjugation system, but ubiquitination of the GHR itself seems not to be required.
- Subjects :
- Acetylcysteine analogs & derivatives
Acetylcysteine pharmacology
Animals
Blotting, Western
CHO Cells
Cricetinae
Cysteine Proteinase Inhibitors pharmacology
Endocytosis drug effects
Growth Hormone pharmacokinetics
Ligands
Lysine metabolism
Mutagenesis
Precipitin Tests
Protein Binding
Receptors, Somatotropin genetics
Time Factors
Transferrin metabolism
Endocytosis physiology
Peptide Hydrolases metabolism
Proteasome Endopeptidase Complex
Receptors, Somatotropin metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9258
- Volume :
- 275
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 10636847
- Full Text :
- https://doi.org/10.1074/jbc.275.3.1575