Year-end Sale % OFF 
Abstract
Based on recent studies showing that phospholipase D (PLD)1 is associated with intracellular membranes and promotes membrane budding from the trans-Golgi, we tested its possible role in the membrane trafficking of GLUT4 glucose transporters. Using immunofluorescence confocal microscopy, expressed Myc epitope-tagged PLD1 was found to associate with intracellular vesicular structures by a mechanism that requires its N-terminal pleckstrin homology domain. Partial co-localization with expressed GLUT4 fused to green fluorescent protein in both 3T3-L1 adipocytes and Chinese hamster ovary cells was evident. Furthermore, microinjection of purified PLD into cultured adipocytes markedly potentiated the effect of a submaximal concentration of insulin to stimulate GLUT4 translocation to cell surface membranes. Insulin stimulated PLD activity in cells expressing high levels of insulin receptors but no such insulin effect was detected in 3T3-L1 adipocytes. Taken together, these results are consistent with the hypothesis that PLD1 associated with GLUT4-containing membranes acts in a constitutive manner to promote the mechanism of GLUT4 translocation by insulin.
Highlights
Physiological glucose homeostasis in humans is largely dependent on the actions of the hormone insulin, its ability to enhance glucose transport into fat and muscle
Preliminary experiments were conducted to test whether phospholipase D (PLD) activity might be required for insulin stimulation of glucose transport in 3T3-L1 adipocytes
In the present studies, 3T3-L1 adipocytes were incubated with 0.75 or 1.25% 1-butanol or 2-butanol in the presence or absence of insulin prior to assay of deoxyglucose transport
Summary
Insulin stimulated PLD activity in cells expressing high levels of insulin receptors but no such insulin effect was detected in 3T3-L1 adipocytes Taken together, these results are consistent with the hypothesis that PLD1 associated with GLUT4-containing membranes acts in a constitutive manner to promote the mechanism of GLUT4 translocation by insulin. Physiological glucose homeostasis in humans is largely dependent on the actions of the hormone insulin, its ability to enhance glucose transport into fat and muscle Insulin exerts this effect primarily through a process whereby sequestered, intracellular GLUT4 glucose transporter proteins are rapidly redistributed to cell surface membranes where they can catalyze glucose uptake into cells [1,2,3]. Recent results indicate that insulin treatment of adipocytes activates PLD [32, 37], consistent with the hypothesis that stimulation of PI 3-kinase may cause enhanced GTP loading of ARF proteins, which in turn activate the enzyme. PLD may act in a constitutive manner to promote membrane processes involved in insulin-stimulated GLUT4 translocation
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
