The efficient intracellular sequestration of the insulin-regulatable glucose transporter (GLUT-4) is conferred by the NH2 terminus

RC Piper, C Tai, JW Slot, CS Hahn, CM Rice… - The Journal of cell …, 1992 - rupress.org
RC Piper, C Tai, JW Slot, CS Hahn, CM Rice, H Huang, DE James
The Journal of cell biology, 1992rupress.org
GLUT-4 is the major facilitative glucose transporter isoform in tissues that exhibit insulin-
stimulated glucose transport. Insulin regulates glucose transport by the rapid translocation of
GLUT-4 from an intracellular compartment to the plasma membrane. A critical feature of this
process is the efficient exclusion of GLUT-4 from the plasma membrane in the absence of
insulin. To identify the amino acid domains of GLUT-4 which confer intracellular
sequestration, we analyzed the subcellular distribution of chimeric glucose transporters …
GLUT-4 is the major facilitative glucose transporter isoform in tissues that exhibit insulin-stimulated glucose transport. Insulin regulates glucose transport by the rapid translocation of GLUT-4 from an intracellular compartment to the plasma membrane. A critical feature of this process is the efficient exclusion of GLUT-4 from the plasma membrane in the absence of insulin. To identify the amino acid domains of GLUT-4 which confer intracellular sequestration, we analyzed the subcellular distribution of chimeric glucose transporters comprised of GLUT-4 and a homologous isoform, GLUT-1, which is found predominantly at the cell surface. These chimeric transporters were transiently expressed in CHO cells using a double subgenomic recombinant Sindbis virus vector. We have found that wild-type GLUT-4 is targeted to an intracellular compartment in CHO cells which is morphologically similar to that observed in adipocytes and muscle cells. Sindbis virus-produced GLUT-1 was predominantly expressed at the cell surface. Substitution of the GLUT-4 amino-terminal region with that of GLUT-1 abolished the efficient intracellular sequestration of GLUT-4. Conversely, substitution of the NH2 terminus of GLUT-1 with that of GLUT-4 resulted in marked intracellular sequestration of GLUT-1. These data indicate that the NH2-terminus of GLUT-4 is both necessary and sufficient for intracellular sequestration.
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