Aldolase mediates the association of F-actin with the insulin-responsive glucose transporter GLUT4
Aldolase mediates the association of F-actin with the insulin-responsive glucose transporter GLUT4
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DOI：
10.1074/jbc.274.25.17742
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发表时间：
1999-06-18
影响因子：
4.8
通讯作者：
Saltiel, AR
中科院分区：
文献类型：
--
作者：
Kao, AW;Noda, Y;Saltiel, AR
为了识别与胰岛素响应性葡萄糖转运蛋白 (GLUT4) 相互作用的潜在蛋白质，我们生成了谷胱甘肽 S-转移酶 (GST) 和 GLUT4 (GST-G4) 或 GLUT1 (GST-G1) 的最后 30 个氨基酸的融合蛋白。这些羧基末端融合蛋白与脂肪细胞提取物的孵育揭示了 GLUT4 与果糖 1,6-二磷酸醛缩酶的特异性相互作用。在醛缩酶存在的情况下，GST-G4（而非 GST-G1）能够与丝状 (F)-肌动蛋白共沉淀。通过与醛缩酶底物、果糖 1,6-二磷酸或甘油醛 8-磷酸一起孵育，可以防止这种相互作用。免疫荧光共聚焦显微镜显示完整的 3T3L1 脂肪细胞中醛缩酶和 GLUT4 存在显着的共定位，并在胰岛素刺激后减少。将果糖 1,6-二磷酸或代谢抑制剂 P-脱氧葡萄糖（两种破坏醛缩酶和肌动蛋白之间相互作用的药物）引入透化的 3T3L1 脂肪细胞中，可抑制胰岛素刺激的 GLUT4 胞吐作用，而不影响 GLUT4 内吞作用。此外，显微注射醛缩酶特异性抗体也抑制胰岛素刺激的 GLUT4 易位。这些数据表明醛缩酶充当 GLUT4 的支架蛋白，并且葡萄糖代谢可能为胰岛素对葡萄糖转运的调节提供负反馈信号。
To identify potential proteins interacting with the insulin-responsive glucose transporter(GLUT4), we generated fusion proteins of glutathione S-transferase (GST) and the final 30 amino acids from GLUT4 (GST-G4) or GLUT1 (GST-G1). Incubation of these carboxyl-terminal fusion proteins with adipocyte cell extracts revealed a specific interaction of GLUT4 with fructose 1,6-bisphosphate aldolase. In the presence of aldolase, GST-G4 but not GST-G1 was able to co-pellet with filamentous (F)-actin. This interaction was prevented by incubation with the aldolase substrates, fructose 1,6-bisphosphate or glyceraldehyde 8-phosphate. Immunofluorescence confocal microscopy demonstrated a significant co-localization of aldolase and GLUT4 in intact 3T3L1 adipocytes, which decreased following insulin stimulation. Introduction into permeabilized 3T3L1 adipocytes of fructose 1,6-bisphosphate or the metabolic inhibitor P-deoxyglucose, two agents that disrupt the interaction between aldolase and actin, inhibited insulin-stimulated GLUT4 exocytosis without affecting GLUT4 endocytosis. Furthermore, microinjection of an aldolase-specific antibody also inhibited insulin-stimulated GLUT4 translocation. These data suggest that aldolase functions as a scaffolding protein for GLUT4 and that glucose metabolism may provide a negative feedback signal for the regulation of glucose transport by insulin.