Translocation of the insulin-regulated aminopeptidase to the cell surface: detection by radioligand binding

H Demaegdt, L Smitz, J-P De Backer, M T Le, M Bauwens, E Szemenyei, G Tóth, Y Michotte, P Vanderheyden, G Vauquelin

Onderzoeksoutput: Articlepeer review

14 Citaten (Scopus)

Samenvatting

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.

EXPERIMENTAL APPROACH: After stimulation of the cells with insulin, internalization of IRAP was inhibited by the addition of phenyl arsine oxide (PAO). Then, cell-surface IRAP was detected by the high-affinity binding of radiolabelled angiotensin (Ang) IV (either 125I or 3H).

KEY RESULTS: We monitored the time- and concentration dependence of insulin-mediated translocation of IRAP in both cell lines and 3T3-L1 adipocytes. A plateau was reached between 6 and 8 min, and 10(-7) M insulin led to the highest amount of IRAP at the cell surface.

CONCLUSIONS AND IMPLICATIONS: Based on the capacity of the IRAP apoenzyme to display high affinity for radiolabelled Ang IV and on the ability of PAO to inhibit IRAP internalization, we developed a more direct and faster method to measure insulin-mediated translocation of IRAP to the cell surface.

Originele taal-2English
Pagina's (van-tot)872-81
Aantal pagina's10
TijdschriftBritish Journal of Pharmacology
Volume154
Nummer van het tijdschrift4
DOI's
StatusPublished - jun 2008

Vingerafdruk

Duik in de onderzoeksthema's van 'Translocation of the insulin-regulated aminopeptidase to the cell surface: detection by radioligand binding'. Samen vormen ze een unieke vingerafdruk.

Citeer dit