Functional characterization and tissue localization of the facilitative glucose transporter GLUT12
Functional characterization and tissue localization of the facilitative glucose transporter GLUT12
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DOI：
10.1093/jb/mvaa090
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发表时间：
2020-12-01
影响因子：
2.7
通讯作者：
Omote, Hiroshi
中科院分区：
文献类型：
--
作者：
Matsuo, Shunsuke;Hiasa, Miki;Omote, Hiroshi
促进性葡萄糖转运蛋白（GLUTs）在葡萄糖利用和体内平衡中起着至关重要的作用。GLUT12最初被分离为一种新的glut4样转运蛋白，参与胰岛素依赖性葡萄糖转运。然而，GLUT12的组织分布和生化特性尚不清楚。在这项研究中，我们研究了GLUT12的基本动力学性质和组织分布。人GLUT12和GLUT1过表达并采用Ni-NTA柱层析纯化。重组的蛋白脂质体具有时间依赖性的d -葡萄糖转运活性，可被根皮素和脱氢抗坏血酸抑制。葡萄糖转运的剂量依赖性显示，K-M和V-max值分别为6.4 mM和1.2 mu mol/mg/min，表明GLUT12是一种高亲和型GLUT。ATP、葡萄糖-1-磷酸、葡萄糖-6-磷酸和双糖（性质与GLUT1相似）抑制GLUT12的葡萄糖转运。间接免疫组化显示小鼠谷氨酸- 12分布于肾远端小管、集管顶端区和空肠上皮细胞。除了这些细胞外，GLUT12还存在于肾上腺髓质、垂体前叶以及甲状腺和幽门腺的染色质细胞中。这些组织分布表明，除了胰岛素依赖型葡萄糖转运外，GLUT12还具有独特的功能。
Facilitative glucose transporters (GLUTs) play crucial roles in glucose utilization and homeostasis. GLUT12 was initially isolated as a novel GLUT4-like transporter involved in insulin-dependent glucose transport. However, tissue distribution and biochemical properties of GLUT12 are not well understood. In this study, we investigated the basic kinetic properties and tissue distribution of GLUT12. Human GLUT12 and GLUT1 were overexpressed and purified using Ni-NTA column chromatography. Reconstituted proteoliposomes showed time-dependent D-glucose transport activity, which was inhibited by phloretin and dehydroascorbate. Dose dependence of glucose transport revealed a K-M and V-max values of 6.4 mM and 1.2 mu mol/mg/min, respectively, indicating that GLUT12 is a high-affinity type GLUT. Glucose transport by GLUT12 was inhibited by ATP and glucose-1-phosphate, glucose-6-phosphate and disaccharides (properties similar to those of GLUT1). Indirect immunohistochemistry revealed the distribution of mouse GLUT12 in the apical region of distal tubules and collecting ducts in the kidney and epithelial cells of the jejunum. In addition to these cells, GLUT12 was present in chromaffin cells in the adrenal medulla, the anterior pituitary lobe, as well as the thyroid and pyloric glands. These tissue distributions suggest a unique function of GLUT12, besides that of an insulin-dependent glucose transport.