Distinct Distribution and Localization of Rho-kinase in Mouse Epithelial, Muscle and Neural Tissues
Distinct Distribution and Localization of Rho-kinase in Mouse Epithelial, Muscle and Neural Tissues
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DOI：
10.1247/csf.12018
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发表时间：
2012-01-01
影响因子：
1.5
通讯作者：
Mizoguchi, Akira
中科院分区：
文献类型：
--
作者：
Iizuka, Michiro;Kimura, Kazushi;Mizoguchi, Akira
小GTP结合蛋白Rho通过各种效应蛋白在多种细胞功能中起着至关重要的作用。Rho激酶是Rho的关键效应蛋白，由两种亚型ROCK 1和ROCK 2组成。为了阐明ROCK 1和ROCK 2的作用部位，我们在小鼠组织中使用同种型特异性抗体进行了免疫荧光和免疫电镜分析。在大肠和小肠中，ROCK 1免疫反应性主要在上皮细胞中确定，ROCK 2免疫反应性可忽略不计。在这些上皮细胞中，ROCK 1免疫反应分布在质膜上，而ROCK 1免疫金信号定位于细胞-细胞接触和细胞粘附位点，特别是在超微结构水平的粘附连接处。然而，在膀胱上皮中，ROCK 1和ROCK 2信号被鉴定在中间丝，并且ROCK 2信号也在细胞核中观察到。在平滑肌细胞、心肌细胞和骨骼肌细胞中，ROCK 1和ROCK 2也表现出不同的分布。ROCK 1信号定位于平滑肌细胞中的肌动蛋白丝、质膜和质膜附近的囊泡;骨骼肌细胞中的溶酶体;并且在心肌细胞中检测不到。ROCK 2信号定位于平滑肌细胞的肌动蛋白丝和中心体，心肌细胞的闰盘，骨骼肌细胞的Z盘和肌浆网。在脑中，ROCK 1免疫反应分布在神经胶质细胞，而ROCK 2免疫反应观察到神经元。这些结果表明，Rho激酶的两种异构体分布差异，以实现其特定的功能。
The small GTP-binding protein Rho plays a crucial role in a wide variety of cellular functions through various effector proteins. Rho-kinase is a key effector protein of Rho, which is composed of two isoforms, ROCK1 and ROCK2. To clarify the site of action of ROCK1 and ROCK2, we performed immunofluorescence and immunoelectron microscopic analyses using isoform-specific antibodies in mouse tissues. In the large and small intestines, ROCK1 immunoreactivity was predominantly identified in epithelial cells, and ROCK2 immunoreactivity was negligible. In these epithelial cells, ROCK1 immunoreactivity was distributed on plasma membranes, while ROCK1 immunogold signals were localized at cell-cell contacts and cell adhesion sites, especially at the adherens junctions at the ultrastructural level. In the bladder epithelium, however, ROCK1 and ROCK2 signals were identified at intermediate filaments, and ROCK2 signals were also observed in nuclei. In the three types of muscular cells-smooth, cardiac, and skeletal muscle cells-ROCK1 and ROCK2 also showed differential distribution. ROCK1 signals were localized at actin filaments, plasma membranes, and vesicles near plasma membranes in smooth muscle cells; at the lysosomes in skeletal muscle cells; and were undetectable in cardiac muscle cells. ROCK2 signals were localized at actin filaments and centrosomes in smooth muscle cells, at intercalated discs in cardiac muscle cells, and at Z-discs and sarcoplasmic reticulum in skeletal muscle cells. In the brain, ROCK1 immunoreactivity was distributed in glia, whereas ROCK2 immunoreactivity was observed in neurons. These results indicate that the two isoforms of Rho-kinase distribute differentially to accomplish their specific functions.