DOC2B: A Novel Syntaxin-4 Binding Protein Mediating Insulin-Regulated GLUT4 Vesicle Fusion in Adipocytes
| العنوان: | DOC2B: A Novel Syntaxin-4 Binding Protein Mediating Insulin-Regulated GLUT4 Vesicle Fusion in Adipocytes |
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| المؤلفون: | Yoshitaka Nakamori, Akihiko Taguchi, Masahiro Emoto, Shinsuke Uraki, Sachiko Miyamoto, Yoshitomo Oka, Naofumi Fukuda, Yukio Tanizawa |
| المصدر: | Diabetes |
| بيانات النشر: | American Diabetes Association, 2009. |
| سنة النشر: | 2009 |
| مصطلحات موضوعية: | Vesicle fusion, Endocrinology, Diabetes and Metabolism, Vesicle docking, Immunoblotting, Molecular Sequence Data, Nerve Tissue Proteins, Deoxyglucose, Biology, Adenoviridae, Mice, 3T3-L1 Cells, Two-Hybrid System Techniques, Adipocytes, Internal Medicine, Animals, Immunoprecipitation, Insulin, Amino Acid Sequence, Analysis of Variance, Glucose Transporter Type 4, Sequence Homology, Amino Acid, Qa-SNARE Proteins, Calcium-Binding Proteins, Glucose transporter, SNAP25, Biological Transport, Kiss-and-run fusion, Blotting, Northern, Fusion protein, Cell biology, DOC2B, Microscopy, Fluorescence, Biochemistry, biology.protein, Calcium, GLUT4, Signal Transduction, Protein Binding |
| الوصف: | OBJECTIVE— Insulin stimulates glucose uptake in skeletal muscle and adipose tissues primarily by stimulating the translocation of vesicles containing a facilitative glucose transporter, GLUT4, from intracellular compartments to the plasma membrane. The formation of stable soluble N-ethyl-maleimide–sensitive fusion protein [NSF] attachment protein receptor (SNARE) complexes between vesicle-associated membrane protein-2 (VAMP-2) and syntaxin-4 initiates GLUT4 vesicle docking and fusion processes. Additional factors such as munc18c and tomosyn were reported to be negative regulators of the SNARE complex assembly involved in GLUT4 vesicle fusion. However, despite numerous investigations, the positive regulators have not been adequately clarified. RESEARCH DESIGN AND METHODS— We determined the intracellular localization of DOC2b by confocal immunoflorescent microscopy in 3T3-L1 adipocytes. Interaction between DOC2b and syntaxin-4 was assessed by the yeast two-hybrid screening system, immunoprecipitation, and in vitro glutathione S-transferase (GST) pull-down experiments. Cell surface externalization of GLUT4 and glucose uptake were measured in the cells expressing DOC2b constructs or silencing DOC2b. RESULTS— Herein, we show that DOC2b, a SNARE-related protein containing double C2 domains but lacking a transmembrane region, is translocated to the plasma membrane upon insulin stimulation and directly associates with syntaxin-4 in an intracellular Ca2+-dependent manner. Furthermore, this process is essential for triggering GLUT4 vesicle fusion. Expression of DOC2b in cultured adipocytes enhanced, while expression of the Ca2+-interacting domain mutant DCO2b or knockdown of DOC2b inhibited, insulin-stimulated glucose uptake. CONCLUSIONS— These findings indicate that DOC2b is a positive SNARE regulator for GLUT4 vesicle fusion and mediates insulin-stimulated glucose transport in adipocytes. |
| تدمد: | 1939-327X 0012-1797 |
| الوصول الحر: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::7a977fe07fe0be54e26b1616bdc494e9Test https://doi.org/10.2337/db08-0303Test |
| حقوق: | OPEN |
| رقم الانضمام: | edsair.doi.dedup.....7a977fe07fe0be54e26b1616bdc494e9 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 1939327X 00121797 |
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