| Insulin binds to and activates its receptor and initiates a signaling cascade that eventually induces the translocation of the Glut4 glucose transporter from its intracellular locations to the plasma membrane. Initiating this pathway facilitates glucose uptake in fat and skeletal muscle cells. Synip and Syntaxin 4 are two proteins thought to be involved in the recruitment of Glut4-containing vesicles to plasma membrane. Synip associates with Syntaxin 4 when insulin is absent. Insulin signaling triggers the dissociation of the two proteins and allows Syntaxin 4 to complex with VAMP2, which is essential for Glut4 translocation to plasma membrane. Overexpression of a dominant-negative form of Synip prevents Glut4 from translocating to plasma membrane in response to insulin stimulation. Synip together with Syntaxin 4, therefore, regulates Glut 4 transport to plasma membrane. |
