Document Detail


The ESCRT-III subunit hVps24 is required for degradation but not silencing of the epidermal growth factor receptor.
MedLine Citation:
PMID:  16554368     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The endosomal sorting complexes required for transport, ESCRT-I, -II, and -III, are thought to mediate the biogenesis of multivesicular endosomes (MVEs) and endosomal sorting of ubiquitinated membrane proteins. Here, we have compared the importance of the ESCRT-I subunit tumor susceptibility gene 101 (Tsg101) and the ESCRT-III subunit hVps24/CHMP3 for endosomal functions and receptor signaling. Like Tsg101, endogenous hVps24 localized mainly to late endosomes. Depletion of hVps24 by siRNA showed that this ESCRT subunit, like Tsg101, is important for degradation of the epidermal growth factor (EGF) receptor (EGFR) and for transport of the receptor from early endosomes to lysosomes. Surprisingly, however, whereas depletion of Tsg101 caused sustained EGF activation of the mitogen-activated protein kinase pathway, depletion of hVps24 had no such effect. Moreover, depletion of Tsg101 but not of hVps24 caused a major fraction of internalized EGF to accumulate in nonacidified endosomes. Electron microscopy of hVps24-depleted cells showed an accumulation of EGFRs in MVEs that were significantly smaller than those in control cells, probably because of an impaired fusion with lyso-bisphosphatidic acid-positive late endosomes/lysosomes. Together, our results reveal functional differences between ESCRT-I and ESCRT-III in degradative protein trafficking and indicate that degradation of the EGFR is not required for termination of its signaling.
Authors:
Kristi G Bache; Susanne Stuffers; Lene Malerød; Thomas Slagsvold; Camilla Raiborg; Delphine Lechardeur; Sébastien Wälchli; Gergely L Lukacs; Andreas Brech; Harald Stenmark
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2006-03-22
Journal Detail:
Title:  Molecular biology of the cell     Volume:  17     ISSN:  1059-1524     ISO Abbreviation:  Mol. Biol. Cell     Publication Date:  2006 Jun 
Date Detail:
Created Date:  2006-05-29     Completed Date:  2006-08-22     Revised Date:  2011-10-28    
Medline Journal Info:
Nlm Unique ID:  9201390     Medline TA:  Mol Biol Cell     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2513-23     Citation Subset:  IM    
Affiliation:
Department of Biochemistry, Institute for Cancer Research, Norwegian Radium Hospital, Montebello, N-0310 Oslo, Norway.
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MeSH Terms
Descriptor/Qualifier:
Down-Regulation
Endocytosis
Endosomal Sorting Complexes Required for Transport
Endosomes / metabolism,  ultrastructure
Gene Silencing
Hela Cells
Humans
Lysosomes / metabolism
Protein Subunits / metabolism
RNA, Small Interfering / genetics
Receptor, Epidermal Growth Factor / genetics,  metabolism*
Vesicular Transport Proteins / metabolism*
Chemical
Reg. No./Substance:
0/CHMP3 protein, human; 0/Endosomal Sorting Complexes Required for Transport; 0/Protein Subunits; 0/RNA, Small Interfering; 0/Vesicular Transport Proteins; EC 2.7.10.1/Receptor, Epidermal Growth Factor
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