Govers Roland, van der Sluijs Peter, van Donselaar Elly, Slot Jan-Willem, Rabelink Ton J
Department of Vascular Medicine, UMC Utrecht, Utrecht, The Netherlands.
J Histochem Cytochem. 2002 Jun;50(6):779-88. doi: 10.1177/002215540205000604.
Caveolin-1 is a member of a subset of intracellular proteins that regulate endothelial nitric oxide synthase (eNOS) activity. In caveolae, caveolin-1 inhibits eNOS activity via a direct interaction with the enzyme. Previous work has indicated that both eNOS and caveolin-1 are also localized at the perinuclear Golgi complex. Whether caveolin-1 is involved in eNOS regulation in this cell compartment is unknown. Here we studied the localization of eNOS and caveolin-1 in the perinuclear region of primary bovine aortic endothelial cells. By immunofluorescence microscopy we show that both eNOS and caveolin-1 co-localize with Golgi markers. On treatment of the cells with the microtubule-depolymerizing drug nocodazole, the Golgi complex is scattered and caveolin-1 is found in vesicles at the periphery of the cell, while eNOS is localized at large structures near the nucleus. The nocodazole-induced redistribution of eNOS is similar to that of cis-, medial-, and trans-Golgi markers, while the caveolin-1 redistribution resembles that of sec22, a marker for the intermediate compartment. The localization of eNOS and caveolin-1 at distinct perinuclear compartments that behave differently in the presence of nocodazole indicates that eNOS activity is not regulated by caveolin-1 in the Golgi complex.
小窝蛋白-1是调节内皮型一氧化氮合酶（eNOS）活性的细胞内蛋白亚群的成员。在小窝中，小窝蛋白-1通过与该酶直接相互作用来抑制eNOS活性。先前的研究表明，eNOS和小窝蛋白-1也定位于核周高尔基体复合体。小窝蛋白-1是否参与该细胞区室中eNOS的调节尚不清楚。在这里，我们研究了eNOS和小窝蛋白-1在原代牛主动脉内皮细胞核周区域的定位。通过免疫荧光显微镜检查，我们发现eNOS和小窝蛋白-1均与高尔基体标志物共定位。在用微管解聚药物诺考达唑处理细胞后，高尔基体复合体分散，小窝蛋白-1存在于细胞周边的囊泡中，而eNOS定位于细胞核附近的大结构中。诺考达唑诱导的eNOS重新分布类似于顺式、中间和反式高尔基体标志物的重新分布，而小窝蛋白-1的重新分布类似于中间区室标志物sec22的重新分布。在存在诺考达唑的情况下，eNOS和小窝蛋白-1定位于不同的核周区室且表现不同，这表明高尔基体复合体中的eNOS活性不受小窝蛋白-1的调节。
