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The facilitative glucose transporter, GLUT4 undergoes insulin-dependent movement to the cell surface in adipocytes. The magnitude of the insulin effect is much greater for GLUT4 than other recycling proteins such as the CD-MPR. In the present study we have studied the colocalisation of these proteins in adipocytes in an effort to explain this selective(More)
ADP-ribosylation factors (ARFs) play important roles in both constitutive and regulated membrane trafficking to the plasma membrane in other cells. Here we have examined their role in insulin-stimulated GLUT4 translocation in 3T3-L1 adipocytes. These cells express ARF5 and ARF6. ARF5 was identified in the soluble protein and intracellular membranes; in(More)
Vesicle-associated membrane protein 2 (VAMP2) has been implicated in the insulin-regulated trafficking of GLUT4 in adipocytes. It has been proposed that VAMP2 co-localizes with GLUT4 in a postendocytic storage compartment (Martin, S., Tellam, J., Livingstone, C., Slot, J. W., Gould, G. W., and James, D. E. (1996) J. Cell Biol. 134, 625-635), suggesting that(More)
Insulin and guanosine-5'-O-(3-thiotriphosphate) (GTPgammaS) both stimulate glucose transport and translocation of the insulin-responsive glucose transporter 4 (GLUT4) to the plasma membrane in adipocytes. Previous studies suggest that these effects may be mediated by different mechanisms. In this study we have tested the hypothesis that these agonists(More)
Insulin increases the exocytosis of many soluble and membrane proteins in adipocytes. This may reflect a general effect of insulin on protein export from the trans Golgi network. To test this hypothesis, we have compared the trafficking of the secreted serine protease adipsin and the integral membrane proteins GLUT4 and transferrin receptors in 3T3-L1(More)
The ferroxidase activity of caeruloplasmin (EC 1.16.3.1) is an important antioxidant defence mechanism in man. In chronic renal failure proteins become carbamylated as a result of reactions with urea-derived cyanate. We have therefore investigated the effects of carbamylation on the ferroxidase activity of caeruloplasmin. Increasing degrees of carbamylation(More)
The available data suggest that GLUT4 does populate the recycling endosomal system to some extent, but that a large proportion of the intracellular GLUT4 resides in a compartment that is devoid of transferrin receptors and may have properties more akin to specialized secretory vesicles. The study of the nature and biogenesis of this compartment will provide(More)
Using the coupling between a standard single-mode fiber and single higher-order modes in a high-index overlay waveguide, we demonstrate a wavelength-filtering device with a channel-dropping response. Two types of filter are described. One uses a thin overlay waveguide, giving a single tunable dropped band response in the 1.2-1.6-microm wavelength region(More)