Document Detail


Turnover of the transferrin receptor is not influenced by removing most of the extracellular domain.
MedLine Citation:
PMID:  1939155     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We treated intact cells with trypsin to remove most of the external domain of the transferrin receptor and investigated what effect the absence of the external domain had on the turnover of the fragment that remained associated with the cells. To detect the cell-associated tryptic fragment, which contains a small amount of the external domain, the transmembrane domain, and the cytoplasmic domain, we prepared an anti-peptide antibody against a segment of the cytoplasmic domain. This antibody specifically immunoprecipitated the intact transferrin receptor as well as a 21-kDa peptide from trypsin-treated HeLa cells. Several lines of evidence indicated that the 21-kDa peptide was the cell-associated tryptic fragment of the transferrin receptor. The fragment was only present in trypsin-treated cells; the fragment migrated as a dimer in nonreducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis, as it should if it were derived from the transferrin receptor; a goat antibody prepared to the purified human transferrin receptor also precipitated the 21-kDa peptide from trypsinized cells. In addition, treating the tryptic fragment with neuraminidase increased the electrophoretic mobility in sodium dodecyl sulfate-polyacrylamide gels, suggesting the fragment contained O-linked carbohydrate. When cells were trypsinized and then incubated at 37 degrees C, the half-life of the tryptic fragment (15 +/- 4 h) was not significantly different than the half-life of the intact receptor (19 +/- 6 h). This indicates that removing 95% of the external domain of the transferrin receptor has little effect on processes operating in the turnover of the receptor.
Authors:
E A Rutledge; C A Mikoryak; R K Draper
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  266     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  1991 Nov 
Date Detail:
Created Date:  1991-12-13     Completed Date:  1991-12-13     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  21125-30     Citation Subset:  IM    
Affiliation:
Molecular and Cell Biology Program, University of Texas, Dallas, Richardson 75083-0688.
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MeSH Terms
Descriptor/Qualifier:
Amino Acid Sequence
Cytoplasm
Disulfides
Extracellular Space
Hela Cells
Humans
Molecular Sequence Data
Molecular Weight
Peptide Fragments / chemistry,  immunology
Precipitin Tests
Receptors, Transferrin / chemistry,  metabolism*
Structure-Activity Relationship
Trypsin / pharmacology
Grant Support
ID/Acronym/Agency:
GM-32042/GM/NIGMS NIH HHS
Chemical
Reg. No./Substance:
0/Disulfides; 0/Peptide Fragments; 0/Receptors, Transferrin; EC 3.4.21.4/Trypsin

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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