Identification of an insulin-responsive, slow endocytic recycling mechanism in Chinese hamster ovary cells
Identification of an insulin-responsive, slow endocytic recycling mechanism in Chinese hamster ovary cells
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DOI：
10.1074/jbc.273.28.17968
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发表时间：
1998-07-10
影响因子：
4.8
通讯作者：
McGraw, TE
中科院分区：
文献类型：
--
作者：
Johnson, AO;Subtil, A;McGraw, TE
在脂肪细胞中，胰岛素调节的氨基肽酶(IRAP)通过与GLUT4葡萄糖转运体相同的胰岛素调节的循环途径进行运输。我们发现，在中国仓鼠卵巢细胞中，含有IRAP的胞内区与转铁蛋白受体的跨膜区和胞外区融合的嵌合体在中国仓鼠卵巢细胞中缓慢循环和快速内化。形态研究表明，嵌合体缓慢地通过一般的内体回收隔间运输，而不是被分类到专门的回收途径。IRAP胞质结构域中的二亮氨酸序列突变为丙氨酸的嵌合体被快速内化和快速循环，表明这种二亮氨酸是缓慢循环所必需的，而不是快速内化所必需的。胰岛素刺激嵌合体的循环增加2-3倍，而转铁蛋白受体的循环仅增加1.2倍。胰岛素对嵌合体循环的影响可被一种磷脂酰肌醇S‘-激酶抑制剂Wortmannin阻断。GTP伽马S(鸟苷5‘-3-O-(硫代)三磷酸)可使嵌合体的循环次数增加50%，但对转铁蛋白受体的循环没有影响。在这些研究中，我们在中国仓鼠卵巢细胞中发现了一种新的、缓慢的内吞循环机制，这种机制受到胰岛素的调节。
In adipocytes, the insulin-regulated aminopeptidase (IRAP) is trafficked through the same insulin-regulated recycling pathway as the GLUT4 glucose transporter. We find that a chimera, containing the cytoplasmic domain of IRAP fused to transmembrane and extracellular domains of the transferrin receptor, is slowly recycled and rapidly internalized in Chinese hamster ovary cells. Morphological studies indicate that the chimera is slowly trafficked through the general endosomal recycling compartment rather than being sorted to a specialized recycling pathway. A chimera in which a di-leucine sequence within the cytoplasmic domain of IRAP has been mutated to alanines is rapidly internalized and rapidly recycled, indicating that this di-leucine is required for the slow recycling but not for the rapid internalization. Insulin stimulates a 2-3-fold increase in the recycling of the chimera and only a 1.2-fold increase in the recycling of the transferrin receptor. The effect of insulin on the recycling of the chimera is blocked by wortmannin, a phosphatidylinositol S'-kinase inhibitor. GTP gamma S (guanosine 5'-3-O-(thio)triphosphate) increases the recycling of the chimera by 50% but has no effect on the recycling of the transferrin receptor. In these studies, we have identified in Chinese hamster ovary cells a novel, slow endocytic recycling mechanism that is regulated by insulin.