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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
1
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pubmed:dateCreated |
1990-2-28
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pubmed:abstractText |
The distribution of transferrin receptors (Tf-R) was determined in Clone 9 hepatocytes and compared to that of 215 kDa, cation-independent mannose-6-phosphate receptors (M6P-R) by double labeling. Cells were allowed to take up exogenous human transferrin (Tf) for 5 to 30 min, after which Tf, Tf-R, and M6P-R were localized by immunofluorescence using specific antibodies. All these proteins were found to be concentrated in the juxtanuclear or Golgi region. When Clone 9 cells were treated with NH4Cl to trap M6P-R in endosomes (Brown, W. J., J. Goodhouse, M. G. Farquhar: J. Cell Biol. 103, 1235-1247 (1986)), the distribution of the two receptors differed: Tf-R remained the same as in controls, but M6P-R were localized in large vacuolated endosomes. To carry out double labeling experiments at the electron microscope level, transferrin gold conjugates (Tf-Au) were prepared, and M6P-R were detected by immunoperoxidase labeling. Tf-Au binding to the cell surface was specific as it was reduced approximately 70 to 79% in the presence of excess native Tf. When Clone 9 cells were incubated with Tf-Au at 37 degrees C for 5 to 30 min, or binding of Tf-Au was carried out at 4 degrees C followed by warming to 37 degrees C, Tf-Au was found within a peripheral tubulovesicular network and within multivesicular endosomes that were not labeled with anti-M6P-R. Other multivesicular endosomes of similar size and morphology were heavily labeled for M6P-R but contained little or no Tf-Au. Tf-Au and M6P-R were also found in separate endosomes in cells treated with NH4Cl. Native Tf was localized in the same compartments as Tf-Au by immunoperoxidase labeling of both Clone 9 cells and mouse myeloma cells. We conclude that in Clone 9 hepatocytes, Tf/Tf-R internalized from the cell surface and M6P-R bearing newly synthesized lysosomal enzymes from the Golgi deliver their ligands to two different subpopulations of multivesicular endosomes. The endosomal subpopulation visited by Tf/Tf-R is known to correspond kinetically to early endosomes. The endosomal subpopulation heavily labeled for M6P-R presumably represent a later endosomal compartment which serves as the junction point where endocytosed ligands and newly synthesized lysosomal enzymes enroute to lysosomes meet.
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pubmed:grant | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Ammonium Chloride,
http://linkedlifedata.com/resource/pubmed/chemical/Hexosephosphates,
http://linkedlifedata.com/resource/pubmed/chemical/Mannosephosphates,
http://linkedlifedata.com/resource/pubmed/chemical/Receptor, IGF Type 2,
http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Cell Surface,
http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Transferrin,
http://linkedlifedata.com/resource/pubmed/chemical/Transferrin
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pubmed:status |
MEDLINE
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pubmed:month |
Oct
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pubmed:issn |
0171-9335
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
50
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
132-43
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pubmed:dateRevised |
2011-11-17
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pubmed:meshHeading |
pubmed-meshheading:2558886-Ammonium Chloride,
pubmed-meshheading:2558886-Animals,
pubmed-meshheading:2558886-Clone Cells,
pubmed-meshheading:2558886-Endocytosis,
pubmed-meshheading:2558886-Fluorescent Antibody Technique,
pubmed-meshheading:2558886-Hexosephosphates,
pubmed-meshheading:2558886-Immunoenzyme Techniques,
pubmed-meshheading:2558886-Liver,
pubmed-meshheading:2558886-Lysosomes,
pubmed-meshheading:2558886-Mannosephosphates,
pubmed-meshheading:2558886-Microscopy, Electron,
pubmed-meshheading:2558886-Organelles,
pubmed-meshheading:2558886-Rats,
pubmed-meshheading:2558886-Receptor, IGF Type 2,
pubmed-meshheading:2558886-Receptors, Cell Surface,
pubmed-meshheading:2558886-Receptors, Transferrin,
pubmed-meshheading:2558886-Transferrin
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pubmed:year |
1989
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pubmed:articleTitle |
Transferrin receptors and cation-independent mannose-6-phosphate receptors deliver their ligands to two distinct subpopulations of multivesicular endosomes.
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pubmed:affiliation |
Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510-8002.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
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