TY - JOUR
T1 - Myosin IIA participates in docking of Glut4 storage vesicles with the plasma membrane in 3T3-L1 adipocytes
AU - Chung, Le Thi Kim
AU - Hosaka, Toshio
AU - Harada, Nagakatsu
AU - Jambaldorj, Bayasgalan
AU - Fukunaga, Keiko
AU - Nishiwaki, Yuka
AU - Teshigawara, Kiyoshi
AU - Sakai, Tohru
AU - Nakaya, Yutaka
AU - Funaki, Makoto
N1 - Funding Information:
We would like to thank Prof. Paul Pilch, Boston University, for editing and critical review of this manuscript. We would also like to thank Dr. Shuichi Okada at Gunma University for his generous gift of pcDNA3-myc-Glut4-EGFP. We would also like to thank Dr. Mitsuru Hashiramoto at Kawasaki Medical College for his generous gift of anti-IRAP antibody. We also would like to thank Dr. Keiji Uchiyama, Dr. Kazuaki Mawatari, and Takaaki Shimohata, the University of Tokushima, for valuable advice. This work was supported by a Grant-in-aid for Scientific Research 19300222 (to Y.N.) from the Ministry of Education, Science, and Culture of Japan and sponsored research from the Tokushima Prefecture (to M.F.).
PY - 2010/1/1
Y1 - 2010/1/1
N2 - In adipocytes and myocytes, insulin stimulation translocates glucose transporter 4 (Glut4) storage vesicles (GSVs) from their intracellular storage sites to the plasma membrane (PM) where they dock with the PM. Then, Glut4 is inserted into the PM and initiates glucose uptake into these cells. Previous studies using chemical inhibitors demonstrated that myosin II participates in fusion of GSVs and the PM and increase in the intrinsic activity of Glut4. In this study, the effect of myosin IIA on GSV trafficking was examined by knocking down myosin IIA expression. Myosin IIA knockdown decreased both glucose uptake and exposures of myc-tagged Glut4 to the cell surface in insulin-stimulated cells, but did not affect insulin signal transduction. Interestingly, myosin IIA knockdown failed to decrease insulin-dependent trafficking of Glut4 to the PM. Moreover, in myosin IIA knockdown cells, insulin-stimulated binding of GSV SNARE protein, vesicle-associated membrane protein 2 (VAMP2) to PM SNARE protein, syntaxin 4 was inhibited. These data suggest that myosin IIA plays a role in insulin-stimulated docking of GSVs to the PM in 3T3-L1 adipocytes through SNARE complex formation.
AB - In adipocytes and myocytes, insulin stimulation translocates glucose transporter 4 (Glut4) storage vesicles (GSVs) from their intracellular storage sites to the plasma membrane (PM) where they dock with the PM. Then, Glut4 is inserted into the PM and initiates glucose uptake into these cells. Previous studies using chemical inhibitors demonstrated that myosin II participates in fusion of GSVs and the PM and increase in the intrinsic activity of Glut4. In this study, the effect of myosin IIA on GSV trafficking was examined by knocking down myosin IIA expression. Myosin IIA knockdown decreased both glucose uptake and exposures of myc-tagged Glut4 to the cell surface in insulin-stimulated cells, but did not affect insulin signal transduction. Interestingly, myosin IIA knockdown failed to decrease insulin-dependent trafficking of Glut4 to the PM. Moreover, in myosin IIA knockdown cells, insulin-stimulated binding of GSV SNARE protein, vesicle-associated membrane protein 2 (VAMP2) to PM SNARE protein, syntaxin 4 was inhibited. These data suggest that myosin IIA plays a role in insulin-stimulated docking of GSVs to the PM in 3T3-L1 adipocytes through SNARE complex formation.
KW - Glut4
KW - Myosin IIA
KW - Syntaxin 4
KW - VAMP2
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U2 - 10.1016/j.bbrc.2009.12.004
DO - 10.1016/j.bbrc.2009.12.004
M3 - Article
C2 - 19968963
AN - SCOPUS:72949104129
VL - 391
SP - 995
EP - 999
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
SN - 0006-291X
IS - 1
ER -