Ito Hidenori, Iwamoto Ikuko, Mizutani Kosuke, Morishita Rika, Deguchi Takashi, Nozawa Yoshinori, Asano Tomiko, Nagata Koh-Ichi
Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Human Service Center, 713-8 Kamiya-Cho, Kasugai, Aichi 480-0392, Japan.
Neurosci Res. 2006 Oct;56(2):165-71. doi: 10.1016/j.neures.2006.06.014. Epub 2006 Aug 28.
Rhotekin, an effector of Rho, is highly expressed in the brain but its function 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 raised the possibility that Rhotekin interacts with a PDZ-protein, PIST (PDZ domain protein interacting specifically with TC10) in vitro, and found that these proteins form complex in the rat brain tissues. We then demonstrated that Rhotekin and PIST are expressed in developmental stage-specific manners in the rat brain. In immunofluorescence analyses, Rhotekin and PIST were suggested to co-localize at synapses in rat primary cultured hippocampal neurons. On the other hand, PIST was found to form immunocomplex with another PDZ-binding protein, beta-catenin, in HEK293 cells and in the rat brain, and co-localized with this protein at dendritic filopods. The interaction of PIST with beta-catenin was inhibited by the presence of Rhotekin. These results suggest a possible yet unidentified role of Rhotekin, in harmony with PIST and beta-catenin, in neuronal cells.
Rhotekin是Rho的一种效应蛋白，在大脑中高表达，但其功能几乎未知。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，我们提出了Rhotekin在体外与一种PDZ蛋白PIST（与TC10特异性相互作用的PDZ结构域蛋白）相互作用的可能性，并发现这些蛋白在大鼠脑组织中形成复合物。然后我们证明，Rhotekin和PIST在大鼠大脑中以发育阶段特异性的方式表达。在免疫荧光分析中，Rhotekin和PIST被认为在大鼠原代培养海马神经元的突触处共定位。另一方面，在HEK293细胞和大鼠大脑中，发现PIST与另一种PDZ结合蛋白β-连环蛋白形成免疫复合物，并在树突状丝状伪足处与该蛋白共定位。Rhotekin的存在会抑制PIST与β-连环蛋白的相互作用。这些结果表明，Rhotekin与PIST和β-连环蛋白协同作用，在神经元细胞中可能发挥尚未明确的作用。
