Department of Nutrition and Metabolism, Institute of Health Biosciences, Tokushima University, Tokushima, Japan.
Biochem Biophys Res Commun. 2011 Feb 4;405(1):96-101. doi: 10.1016/j.bbrc.2010.12.134. Epub 2011 Jan 7.
Insulin-responsive aminopeptidase (IRAP) and GLUT4 are two major cargo proteins of GLUT4 storage vesicles (GSVs) that are translocated from a postendosomal storage compartment to the plasma membrane (PM) in response to insulin. The cytoplasmic region of IRAP is reportedly involved in retention of GSVs. In this study, vimentin was identified using the cytoplasmic domain of IRAP as bait. The validity of this interaction was confirmed by pull-down assays and immunoprecipitation in 3T3-L1 adipocytes. In addition, it was shown that GLUT4 translocation to the PM by insulin was decreased in vimentin-depleted adipocytes, presumably due to dispersing GSVs away from the cytoskeleton. These findings suggest that the IRAP binding protein, vimentin, plays an important role in retention of GSVs.
胰岛素反应性氨肽酶（IRAP）和 GLUT4 是 GLUT4 储存小泡（GSV）的两种主要货物蛋白，它们在胰岛素的作用下从内体后储存隔室易位到质膜（PM）。IRAP 的细胞质区域据称参与 GSV 的保留。在这项研究中，使用 IRAP 的细胞质结构域作为诱饵鉴定了波形蛋白。通过 3T3-L1 脂肪细胞中的下拉测定和免疫沉淀证实了这种相互作用的有效性。此外，结果表明，胰岛素诱导的 GLUT4 向 PM 的易位在波形蛋白耗尽的脂肪细胞中减少，这可能是由于 GSV 从细胞骨架上分散。这些发现表明，IRAP 结合蛋白波形蛋白在 GSV 的保留中起重要作用。
