Insulin-induced translocation of CD36 to the plasma membrane is reversible and shows similarity to that of GLUT4.
In cardiac and skeletal muscles, insulin regulates the uptake of long-chain fatty acid (LCFA) via the putative LCFA transporter CD36. Biochemical studies propose an insulin-induced translocation of CD36 from intracellular pools to the plasma membrane (PM), similar to glucose transporter 4 (GLUT4) translocation. To characterize insulin-induced CD36 translocation in intact cells, Chinese hamster ovary (CHO) cells stably expressing CD36 or myc-tagged GLUT4 (GLUT4myc) were created. Immuno-fluorescence microscopy revealed CD36 to be located both intracellularly (in--at least partially--different compartments than GLUT4myc) and at the PM. Upon stimulation with insulin, CD36 translocated to a PM localization similar to that of GLUT4myc; the increase in PM CD36 content, as quantified by surface-protein biotinylation, amounted to 1.7-fold. The insulin-induced CD36 translocation was shown to be phosphatidylinositol-3 kinase-dependent, and reversible (as evidenced by insulin wash-out) in a similar time frame as that for GLUT4. The expression of GLUT4myc in non-stimulated cells, and the insulin-induced increase in PM GLUT4myc correlated with increased deoxyglucose uptake. By contrast, CD36 expression in non-stimulated cells and the insulin-induced increase in PM CD36 were not paralleled by a rise in LCFA uptake, suggesting that in these cells, such increase requires additional proteins, or a protein activation step. Taken together, this study is the first to present morphological evidence for CD36 translocation, and shows this process to resemble GLUT4 translocation.
van Oort
Masja M
MM
Division of Endocrinology and Metabolism, Department of Biology and Institute of Biomembranes, Utrecht University, NL-3584 CH Utrecht, The Netherlands.
van Doorn
Jan M
JM
Bonen
Arend
A
Glatz
Jan F C
JF
van der Horst
Dick J
DJ
Rodenburg
Kees W
KW
Luiken
Joost J F P
JJ
D000818:Animals; D018955:CD36 Antigens / Q000235:genetics / Q000378:metabolism*; D016466:CHO Cells; D002462:Cell Membrane / Q000187:drug effects* / Q000378:metabolism*; D006224:Cricetinae; D003412:Cricetulus; D005227:Fatty Acids / Q000378:metabolism; D051275:Glucose Transporter Type 4 / Q000235:genetics / Q000378:metabolism*; D007328:Insulin / Q000494:pharmacology*; D021381:Protein Transport; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects
D018955:CD36 Antigens; D005227:Fatty Acids; D051275:Glucose Transporter Type 4; D007328:Insulin