Concentration of transferrin receptor in human placental coated vesicles.
Coated vesicles were purified from human placenta by sedimentation, isopycnic centrifugation, and gel filtration. Quantitative Western blotting of the endogenous transferrin receptor (tfR) demonstrated the presence, on average, of roughly one receptor per vesicle. TfR appeared undersaturated with transferrin. After solubilizing vesicles in nonionic detergent, we looked for evidence of tfR interactions with other proteins. Solubilized tfR had an unexpectedly high mobility by gel filtration, apparently resulting from its self-association. This property was not seen in purified tfR or in tfR from a different cell fraction. The tfR complexes, though noncovalent, were largely resistant to conditions that disassemble coat proteins, and they did not appear to contain any other protein species.
Turkewitz
A P
AP
Department of Biochemistry and Molecular Biology, Harvard University, Cambridge, Massachusetts.
Harrison
S C
SC
D002458:Cell Fractionation; D002850:Chromatography, Gel; D003034:Coated Pits, Cell-Membrane / Q000378:metabolism* / Q000648:ultrastructure; D004705:Endocytosis; D011992:Endosomes / Q000378:metabolism*; D006801:Humans; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000378:metabolism; D008854:Microscopy, Electron; D008970:Molecular Weight; D010920:Placenta / Q000378:metabolism* / Q000648:ultrastructure; D011485:Protein Binding; D011990:Receptors, Transferrin / Q000378:metabolism* / Q000648:ultrastructure; D014168:Transferrin / Q000378:metabolism*
D046911:Macromolecular Substances; D008565:Membrane Proteins; D011990:Receptors, Transferrin; D014168:Transferrin