Endocytosis of ABCG2 drug transporter caused by binding of 5D3 antibody: trafficking mechanisms and intracellular fate.
ABCG2, a metabolite and xenobiotic transporter located at the plasma membrane (predominantly in barrier tissues and progenitor cells), undergoes a direct progressive endocytosis process from plasma membrane to intracellular compartments upon binding of 5D3 monoclonal antibody. This antibody is specific to an external epitope on the protein molecule and locks it in a discrete conformation within its activity cycle, presumably providing a structural trigger for the observed internalization phenomenon. Using routine and novel assays, we show that ABCG2 is endocytosed by a mixed mechanism: partially via a rapid, clathrin-dependent pathway and partially in a cholesterol-dependent, caveolin-independent manner. While the internalization process is entirely dynamin-dependent and converges initially at the early endosome, subsequent intracellular fate of ABCG2 is again twofold: endocytosis leads to only partial lysosomal degradation, while a significant fraction of the protein is retained in a post-endosomal compartment with the possibility of at least partial recycling back to the cell surface. This externally triggered, conformation-related trafficking pathway may serve as a general regulatory paradigm for membrane transporters, and its discovery was made possible thanks to consistent application of quantitative methods.
Department of Molecular Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, 12/16 Banacha St., 90-237 Lodz, Poland.
Maciej
M
Studzian
Department of Molecular Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, 12/16 Banacha St., 90-237 Lodz, Poland.
Grzegorz
G
Bartosz
Department of Molecular Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, 12/16 Banacha St., 90-237 Lodz, Poland; Laboratory of Transcriptional Regulation, Institute of Medical Biology PAS, Lodowa 106, 93-232 Lodz, Poland. Electronic address: lpulaski@uni.lodz.pl.
Lukasz
L
Pulaski
D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000378:metabolism*; D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism*; D051242:Caveolin 1 / Q000378:metabolism; D002478:Cells, Cultured; D002784:Cholesterol / Q000494:pharmacology; D002966:Clathrin / Q000378:metabolism; D004285:Dogs; D004705:Endocytosis / Q000187:drug effects / Q000502:physiology; D057809:HEK293 Cells; D019073:HT29 Cells; D006801:Humans; D061986:MCF-7 Cells; D053858:Metabolic Networks and Pathways / Q000187:drug effects; D009363:Neoplasm Proteins / Q000378:metabolism*; D011485:Protein Binding; D021381:Protein Transport / Q000187:drug effects; D022161:Transport Vesicles / Q000187:drug effects / Q000378:metabolism
C116614:ABCG2 protein, human; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D000911:Antibodies, Monoclonal; D051242:Caveolin 1; D002966:Clathrin; D009363:Neoplasm Proteins; D002784:Cholesterol
5D3; ABCG2; Antibody; Endocytosis; Trafficking