Abstract
To investigate the physiological function of the VAMP3 vesicle SNARE (v-SNARE) isoform in the regulation of GLUT4 vesicle trafficking, we generated homozygotic VAMP3 null mice by targeted gene disruption. The VAMP3 null mice had typical growth rate and weight gain, with normal maintenance of fasting serum glucose and insulin levels. Analysis of glucose disposal and insulin sensitivity demonstrated normal insulin and glucose tolerance, with no evidence for insulin resistance. Insulin stimulation of glucose uptake in isolated primary adipocytes was essentially the same for the wild-type and VAMP3 null mice. Similarly, insulin-, hypoxia-, and exercise-stimulated glucose uptake in isolated skeletal muscle did not differ significantly. In addition, other general membrane trafficking events including phagocytosis, pinocytosis, and transferrin receptor recycling were also found to be unaffected in the VAMP3 null mice. Taken together, these data demonstrate that VAMP3 function is not necessary for either regulated GLUT4 translocation or general constitutive membrane recycling.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Adipocytes / metabolism
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Animals
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Blood Glucose / metabolism
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Blotting, Western
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Body Weight / genetics
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Cattle
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Cells, Cultured
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DNA, Complementary / metabolism
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Embryo, Mammalian / metabolism
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Female
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Fibroblasts / metabolism
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Gene Deletion
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Glucose / pharmacokinetics
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Glucose Transporter Type 4
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Homozygote
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Hypoxia
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Insulin / blood
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Insulin / metabolism*
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Male
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Membrane Proteins / chemistry
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Membrane Proteins / genetics*
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Mice
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Models, Genetic
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Monosaccharide Transport Proteins / metabolism
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Muscle Proteins*
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Muscle, Skeletal / metabolism
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Mutagenesis, Site-Directed
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Phagocytosis
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Physical Conditioning, Animal*
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Pinocytosis
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Protein Isoforms
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Receptors, Transferrin / metabolism
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SNARE Proteins
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Sex Factors
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Time Factors
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Tissue Distribution
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Transferrin / metabolism
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Vesicle-Associated Membrane Protein 3
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Vesicular Transport Proteins*
Substances
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Blood Glucose
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DNA, Complementary
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Glucose Transporter Type 4
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Insulin
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Membrane Proteins
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Monosaccharide Transport Proteins
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Muscle Proteins
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Protein Isoforms
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Receptors, Transferrin
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SNARE Proteins
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Slc2a4 protein, mouse
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Transferrin
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Vesicle-Associated Membrane Protein 3
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Vesicular Transport Proteins
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Glucose