title: Regulation of transferrin-induced endocytosis by wild-type and C282Y-mutant HFE in transfected HeLa cells.
abstract: The hereditary hemochromatosis protein HFE is known to complex with the transferrin receptor; however, its function regarding endocytosis of transferrin is unclear. We performed patch-clamp capacitance measurements in transfected HeLa cells carrying wild-type or C282Y-mutant HFE cDNA under the control of a tetracycline-sensitive promoter. Whole cell experiments in cells with suppressed expression of wild-type HFE revealed a decrease in membrane capacitance, reflecting predominance of endocytosis in the presence of transferrin. Cells overexpressing C282Y-mutant HFE displayed less intense capacitance decreases, whereas no significant decrease was observed in cells overexpressing wild-type HFE. The formation of single endocytic vesicles in cells with suppressed expression of wild-type HFE was greatly increased in the presence of transferrin as revealed by cell-attached recordings. According to their calculated diameters, many of these vesicles corresponded to clathrin-coated vesicles. These results suggest that wild-type HFE negatively modulates the endocytic uptake of transferrin. This inhibitory effect is attenuated in cells expressing C282Y-mutant HFE. Time-resolved measurements of cell membrane capacitance provide a powerful tool to study transferrin-induced endocytosis in single cells.
authors.affiliation: Department of Gastroenterology, Faculty of Medicine, University of Heidelberg, D-69115 Heidelberg, Germany. Lukas_Schwake@gmx.net
authors.forename: Lukas
authors.initials: L
authors.lastname: Schwake
authors.forename: Andreas W
authors.initials: AW
authors.lastname: Henkel
authors.forename: Hans D
authors.initials: HD
authors.lastname: Riedel
authors.forename: Thorsten
authors.initials: T
authors.lastname: Schlenker
authors.forename: Matthias
authors.initials: M
authors.lastname: Both
authors.forename: Andrea
authors.initials: A
authors.lastname: Migala
authors.forename: Boris
authors.initials: B
authors.lastname: Hadaschik
authors.forename: Nataly
authors.initials: N
authors.lastname: Henfling
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Stremmel
mesh_terms: D025802:Electric Capacitance; D006680:HLA Antigens / Q000235:genetics* / Q000378:metabolism; D006367:HeLa Cells; D006432:Hemochromatosis / Q000235:genetics*; D000071020:Hemochromatosis Protein; D015395:Histocompatibility Antigens Class I / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D007501:Iron / Q000378:metabolism; D008565:Membrane Proteins; D018408:Patch-Clamp Techniques; D011990:Receptors, Transferrin / Q000378:metabolism; D022142:Secretory Vesicles / Q000378:metabolism; D014168:Transferrin / Q000378:metabolism*; D022161:Transport Vesicles / Q000378:metabolism
chemical_list: C103673:HFE protein, human; D006680:HLA Antigens; D000071020:Hemochromatosis Protein; D015395:Histocompatibility Antigens Class I; D008565:Membrane Proteins; D011990:Receptors, Transferrin; D014168:Transferrin; D007501:Iron