Role of semicarbazide-sensitive amine oxidase on glucose transport and GLUT4 recruitment to the cell surface in adipose cells
Role of semicarbazide-sensitive amine oxidase on glucose transport and GLUT4 recruitment to the cell surface in adipose cells
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DOI：
10.1074/jbc.273.14.8025
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发表时间：
1998-04-03
影响因子：
4.8
通讯作者：
Zorzano, A
中科院分区：
文献类型：
--
作者：
Enrique-Tarancón, G;Marti, L;Zorzano, A
以前的一个丰富的人口的非肾上腺素能咪唑啉-I-2结合位点在脂肪细胞和最近的演示这些结合位点和胺氧化酶之间的相互作用的表征导致我们分析的胺氧化酶活性在膜分离大鼠脂肪细胞。脂肪细胞膜具有大量的氨基脲敏感胺氧化酶（SSAO），SSAO活性和免疫反应性SSAO蛋白在质膜中最高，并且它们在细胞内膜中也是可检测的。囊泡免疫分离分析表明来自大鼠脂肪细胞的含有GLUT 4的囊泡含有大量的SSAO活性和免疫反应性SSAO蛋白，细胞内GLUT 4囊泡的免疫滴定表明，GLUT 4和SSAO共定位于大鼠脂肪细胞的内体区室，SSAO活性也在3 T3-L1脂肪细胞和大鼠骨骼肌的GLUT 4囊泡中发现。在非常低的钒酸盐浓度存在下，在分离的大鼠脂肪细胞中引起葡萄糖转运的显著刺激，所述钒酸盐浓度本身在发挥胰岛素样作用方面无效。在SSAO的特异性抑制剂氨基脲存在下，苄胺和钒酸盐对葡萄糖转运的这种协同作用被完全消除。亚细胞膜分离显示，苄胺和钒酸盐的组合引起GLUT 4向脂肪细胞质膜的募集，苄胺和钒酸盐对葡萄糖转运的刺激作用被过氧化氢酶阻断，这表明过氧化氢产生与SSAO活性耦合起着关键的调节作用，基于这些结果，我们提出SSAO活性可能有助于通过过氧化氢的产生在体内调节脂肪细胞中的GLUT 4运输。
The previous characterization of an abundant population of non-adrenergic imidazoline-I-2 binding sites in adipocytes and the recent demonstration of the interplay between these binding sites and amine oxidases led us to analyze the amine oxidase activity in membranes from isolated rat adipocytes. Adipocyte membranes had substantial levels of semicarbazide-sensitive amine oxidase (SSAO), SSAO activity and immunoreactive SSAO protein were maximal in plasma membranes, and they were also detectable in intracellular membranes, Vesicle immunoisolation analysis indicated that GLUT4-containing vesicles from rat adipocytes contain substantial levels of SSAO activity and immunoreactive SSAO protein, Immunotitration of intracellular GLUT4 vesicles indicated that GLUT4 and SSAO colocalize in an endosomal compartment in rat adipocytes, SSAO activity was also found in GLUT4 vesicles from 3T3-L1 adipocytes and rat skeletal muscle.Benzylamine, a substrate of SSAO activity, caused a marked stimulation of glucose transport in isolated rat adipocytes in the presence of very low vanadate concentrations that by themselves were ineffective in exerting insulin-like effects. This synergistic effect of benzylamine and vanadate on glucose transport was totally abolished in the presence of semicarbazide, a specific inhibitor of SSAO. Subcellular membrane fractionation revealed that the combination of benzylamine and vanadate caused a recruitment of GLUT4 to the plasma membrane of adipose cells, The stimulatory effects of benzylamine and vanadate on glucose transport were blocked by catalase, suggesting that hydrogen peroxide production coupled to SSAO activity plays a crucial regulatory role, Based on these results we propose that SSAO activity might contribute through hydrogen peroxide production to the in vivo regulation of GLUT4 trafficking in adipose cells.