Translocation of the insulin-regulated aminopeptidase to the cell surface: detection by radioligand binding
Demaegdt, H × Smitz, L De Backer, J-P Bauwens, Matthias Szemenyei, E Toth, G Michotte, Y Vanderheyden, P Vauquelin, G #
Scientific & Medical Division, Macmillan Press
British Journal of Pharmacology vol:154 issue:4 pages:872-881
Background and purpose: Insulin-regulated aminopeptidase ( IRAP) and the insulin-dependent glucose transporter GLUT4 colocalize in specific intracellular vesicles (that is, GLUT4 vesicles). These vesicles move slowly to the cell surface, but their translocation is markedly enhanced by insulin, resulting in higher glucose uptake. Previous studies of the insulin-mediated translocation of IRAP to the cell surface have been hampered by the laborious detection of IRAP at the cell surface. We aimed to develop a more direct and faster method to detect IRAP. To this end, we used model systems with well-characterized IRAP: CHO-K1 cells expressing endogenous IRAP and recombinant HEK293 cells expressing human IRAP. A more widespread application of the method was demonstrated by the use of 3T3-L1 adipocytes.