Insulin-stimulated fusion of GLUT4 vesicles to plasma membrane is dependent on wortmannin-sensitive insulin signaling pathway in 3T3-L1 adipocytes.
It is established that wortmannin which completely inhibits class IA PI 3-kinase activation abrogated the insulin-dependent translocation of GLUT4 to the plasma membrane in adipocytes and skeletal muscle. However, it was not clear which steps wortmannin inhibited during the whole translocation process of GLUT4. We have now dissected the each steps of the GLUT4 trafficking in 3T3-L1 adipocytes using exogenously-expressed GLUT4 reporter in combination with plasma membrane lawn assay. We showed that 100 nM wortmannin inhibited the fusion of GLUT4 vesicles to the plasma membrane without affecting the movement and the subsequent tethering/docking event of GLUT4 vesicles to the membrane in 3T3-L1 adipocytes. These results suggest that wortmannin-sensitive insulin signaling pathway plays a crucial role in the fusion step of GLUT4 vesicles to the plasma membrane in 3T3-L1 adipocytes.
Kawaguchi
Takayuki
T
Division of Diabetes, Metabolism, and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, Chuo-ku, Kobe 650-0017, Japan.
Tamori
Yoshikazu
Y
Yoshikawa
Mari
M
Kanda
Hajime
H
Kasuga
Masato
M
D041721:3T3-L1 Cells; D017667:Adipocytes / Q000187:drug effects* / Q000378:metabolism*; D000730:Androstadienes / Q000494:pharmacology*; D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D051275:Glucose Transporter Type 4 / Q000235:genetics / Q000378:metabolism*; D007328:Insulin / Q000494:pharmacology*; D051379:Mice; D011485:Protein Binding; D021381:Protein Transport; D015398:Signal Transduction / Q000187:drug effects*; D013379:Substrate Specificity; D000077191:Wortmannin
D000730:Androstadienes; D051275:Glucose Transporter Type 4; D007328:Insulin; D005947:Glucose; D000077191:Wortmannin