Zhao Ping, Yang Lu, Lopez Jamie A, Fan Junmei, Burchfield James G, Bai Li, Hong Wanjin, Xu Tao, James David E
National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
J Cell Sci. 2009 Oct 1;122(Pt 19):3472-80. doi: 10.1242/jcs.047449.
Vesicle transport in eukaryotic cells is regulated by SNARE proteins, which play an intimate role in regulating the specificity of vesicle fusion between discrete intracellular organelles. In the present study we investigated the function and plasticity of v-SNAREs in insulin-regulated GLUT4 trafficking in adipocytes. Using a combination of knockout mice, v-SNARE cleavage by clostridial toxins and total internal reflection fluorescence microscopy, we interrogated the function of VAMPs 2, 3 and 8 in this process. Our studies reveal that the simultaneous disruption of VAMPs 2, 3 and 8 completely inhibited insulin-stimulated GLUT4 insertion into the plasma membrane, due to a block in vesicle docking at the plasma membrane. These defects could be rescued by re-expression of VAMP2, VAMP3 or VAMP8 alone, but not VAMP7. These data indicate a plasticity in the requirement for v-SNAREs in GLUT4 trafficking to the plasma membrane and further define an important role for the v-SNARE proteins in pre-fusion docking of vesicles.
真核细胞中的囊泡运输由SNARE蛋白调控，这些蛋白在调节离散细胞内细胞器之间囊泡融合的特异性方面发挥着密切作用。在本研究中，我们研究了v-SNAREs在脂肪细胞胰岛素调节的GLUT4转运中的功能和可塑性。通过结合使用基因敲除小鼠、肉毒杆菌毒素对v-SNARE的切割以及全内反射荧光显微镜，我们探究了VAMPs 2、3和8在此过程中的功能。我们的研究表明，VAMPs 2、3和8的同时缺失完全抑制了胰岛素刺激的GLUT4插入质膜，这是由于囊泡在质膜处对接受阻所致。单独重新表达VAMP2、VAMP3或VAMP8可以挽救这些缺陷，但VAMP7不能。这些数据表明在GLUT4向质膜转运过程中对v-SNAREs的需求具有可塑性，并进一步确定了v-SNARE蛋白在囊泡预融合对接中的重要作用。
