Translocation of endothelial nitric-oxide synthase involves a ternary complex with caveolin-1 and NOSTRIN.
Translocation of endothelial nitric-oxide synthase involves a ternary complex with caveolin-1 and NOSTRIN.
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DOI：
10.1091/mbc.e05-08-0709
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发表时间：
2006-09
影响因子：
3.3
通讯作者：
K. Schilling;N. Opitz;A. Wiesenthal;S. Oess;R. Tikkanen;W. Müller-Esterl;Ann Icking
中科院分区：
文献类型：
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作者：
K. Schilling;N. Opitz;A. Wiesenthal;S. Oess;R. Tikkanen;W. Müller-Esterl;Ann Icking
最近，我们鉴定了一种新的内皮型一氧化氮合酶(ENOS)相互作用蛋白NOSTRIN(意为eNOS运输诱导物)，它能在eNOS过度表达时降低eNOS的活性，并诱导eNOS移位离开质膜。在这里，我们证明了NOSTRIN直接与小窝-1结合，小窝-1是一种公认的eNOS抑制剂。由于这种相互作用发生在小窝蛋白的N端(1-61位)和NOSTRIN的中心结构域(323-434位)之间，因此这两种蛋白都可以独立地与eNOS结合。我们一直能够证明在中国仓鼠卵巢(CHO)-eNOS细胞中存在NOSTRIN、eNOS和小窝蛋白-1的三元复合体。在人脐静脉内皮细胞(HUVECs)中，三元复合体在融合或凝血酶刺激下聚集在质膜上。在CHO-eNOS细胞中，NOSTRIN介导的eNOS易位涉及小窝蛋白，这一过程很可能代表小窝运输。因此，NOSTRIN/eNOS/小窝蛋白的运输受到质膜中肌动蛋白细丝状态或胆固醇水平的影响。在空泡运输过程中，NOSTRIN作为一个适配器来招募介体，如对膜分裂至关重要的Dynamin-2。我们认为，NOSTRIN、小窝蛋白-1和eNOS之间的三元复合体介导eNOS的移位，这对eNOS在细胞内的活性和可用性具有重要意义。
Recently, we characterized a novel endothelial nitric-oxide synthase (eNOS)-interacting protein, NOSTRIN (for eNOS-trafficking inducer), which decreases eNOS activity upon overexpression and induces translocation of eNOS away from the plasma membrane. Here, we show that NOSTRIN directly binds to caveolin-1, a well-established inhibitor of eNOS. Because this interaction occurs between the N terminus of caveolin (positions 1-61) and the central domain of NOSTRIN (positions 323-434), it allows for independent binding of each of the two proteins to eNOS. Consistently, we were able to demonstrate the existence of a ternary complex of NOSTRIN, eNOS, and caveolin-1 in Chinese hamster ovary (CHO)-eNOS cells. In human umbilical vein endothelial cells (HUVECs), the ternary complex assembles at the plasma membrane upon confluence or thrombin stimulation. In CHO-eNOS cells, NOSTRIN-mediated translocation of eNOS involves caveolin in a process most likely representing caveolar trafficking. Accordingly, trafficking of NOSTRIN/eNOS/caveolin is affected by altering the state of actin filaments or cholesterol levels in the plasma membrane. During caveolar trafficking, NOSTRIN functions as an adaptor to recruit mediators such as dynamin-2 essential for membrane fission. We propose that a ternary complex between NOSTRIN, caveolin-1, and eNOS mediates translocation of eNOS, with important implications for the activity and availability of eNOS in the cell.