Sudo Kaori, Ito Hidenori, Iwamoto Ikuko, Morishita Rika, Asano Tomiko, Nagata Koh-ichi
Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Human Service Center, 713-8 Kamiya, Kasugai, Aichi, Japan.
Neurosci Res. 2006 Dec;56(4):347-55. doi: 10.1016/j.neures.2006.08.003. Epub 2006 Sep 18.
Rhotekin, an effector of Rho, is highly expressed in the brain but its function(s) in neurons is almost unknown. In an attempt to define the properties of Rhotekin in neuronal cells, we focused on its interaction with polarity-related molecules. In the present study, we identified a PDZ protein, Lin-7B, as a binding partner for Rhotekin by yeast two-hybrid screening of human brain cDNA library. We then found that Rhotekin interacts with Lin-7B in in vitro pull-down assays, and forms an immunocomplex in COS7 cells and the rat brain. The C-terminal three amino acids of Rhotekin were essential for the interaction with Lin-7B. Their binding affinity became increased in the presence of active RhoA in the COS7 cell expression system. In addition, immunohistochemical analyses demonstrated that Lin-7 as well as Rhotekin is enriched in neurons. These results suggest that Lin-7 plays some role in neuronal functions in concert with Rho/Rhotekin signals.
Rhotekin是Rho的一种效应蛋白，在大脑中高表达，但其在神经元中的功能几乎未知。为了确定Rhotekin在神经元细胞中的特性，我们重点研究了它与极性相关分子的相互作用。在本研究中，我们通过对人脑cDNA文库进行酵母双杂交筛选，鉴定出一种PDZ蛋白Lin-7B作为Rhotekin的结合伴侣。然后我们发现在体外下拉实验中Rhotekin与Lin-7B相互作用，并在COS7细胞和大鼠脑中形成免疫复合物。Rhotekin的C末端三个氨基酸对于与Lin-7B的相互作用至关重要。在COS7细胞表达系统中，活性RhoA的存在会增加它们的结合亲和力。此外，免疫组织化学分析表明Lin-7和Rhotekin在神经元中均有富集。这些结果表明，Lin-7与Rho/Rhotekin信号协同在神经元功能中发挥一定作用。
