Characterization of GLUT4-containing vesicles in 3T3-L1 adipocytes by total internal reflection fluorescence microscopy  

作　　者：WANG Yan1,2,ZHANG JinZhong1,2,CHEN Yu1,2,JIANG Li1,2,JI Wei1,2 & XU Tao1 1 National Laboratory of Biomacromolecules,Institute of Biophysics,Chinese Academy of Sciences,Beijing 100101,China 2 Graduate University of Chinese Academy of Sciences,Beijing 100049,China 

出　　处：《Science China(Life Sciences)》2009年第7期665-671,共7页中国科学（生命科学英文版）

基　　金：Supported by the National Natural Science Foundation of China (Grant Nos. 30470448 and 30130230);the National key Basic Research Program of China (Grant No. 2004CB720000);the Knowledge Innovative Program of The Chinese Academy of Sciences (Grant Nos. KSCX2-SW-224 and Y2004018);the Li Foundation and the Sinogerman Scientific Center

摘　　要：Insulin-responsive GLUT4(glucose transporter 4) translocation plays a major role in regulating glucose uptake in adipose tissue and muscle.Whether or not there is a specialized secretory GSV(GLUT4 storage vesicle) pool,and more importantly how GSVs are translocated to the PM(plasma membrane) under insulin stimulation is still under debate.In the present study,we systematically analyzed the dynamics of a large number of single GLUT4-containing vesicles in 3T3-L1 adipocytes by TIRFM(total internal reflection fluorescence microscopy).We found that GLUT4-containing vesicles can be classified into three groups according to their mobility,namely vertical,stable,and lateral GLUT4-containing vesicles.Among these groups,vertical GLUT4-containing vesicles exclude transferrin receptors and move towards the PM specifically in response to insulin stimulation,while stable and lateral GLUT4-containing vesicles contain transferrin receptors and show no insulin responsiveness.These data demonstrate that vertical GLUT4-containing vesicles correspond to specialized secretory GSVs,which approach the PM directly and bypass the constitutive recycling pathway.Insulin-responsive GLUT4(glucose transporter 4) translocation plays a major role in regulating glucose uptake in adipose tissue and muscle.Whether or not there is a specialized secretory GSV(GLUT4 storage vesicle) pool,and more importantly how GSVs are translocated to the PM(plasma membrane) under insulin stimulation is still under debate.In the present study,we systematically analyzed the dynamics of a large number of single GLUT4-containing vesicles in 3T3-L1 adipocytes by TIRFM(total internal reflection fluorescence microscopy).We found that GLUT4-containing vesicles can be classified into three groups according to their mobility,namely vertical,stable,and lateral GLUT4-containing vesicles.Among these groups,vertical GLUT4-containing vesicles exclude transferrin receptors and move towards the PM specifically in response to insulin stimulation,while stable and lateral GLUT4-containing vesicles contain transferrin receptors and show no insulin responsiveness.These data demonstrate that vertical GLUT4-containing vesicles correspond to specialized secretory GSVs,which approach the PM directly and bypass the constitutive recycling pathway.

关 键 词：GLUT4 IRAP-pHluorin GSV transferring TIRFM 

分 类 号：Q2-3[生物学—细胞生物学]