Obscurin Signaling Through its Rho-GEF and PH Domains

描述（由申请人提供）： 骨骼肌是由称为肌节的重复收缩单位组成的高度组织化的结构。在胚胎发育过程中，肌节组装并组织形成肌原纤维。形成肌节的蛋白质和支持收缩装置的细胞骨架的缺陷可导致肌营养不良症。在胚胎发生和出生后早期的肌原纤维正常发育中导致基因转录的信号传导途径被认为与在成年肌肉的生理和病理性肥大状态中导致基因转录的信号传导途径相同。Obscurin是近年来发现的骨骼肌巨蛋白，含有一个信号结构域Rho-GEF结构域，可能参与肌原纤维的形成。我发现Ran结合蛋白RanBPM是obscurin的Rho-GEF结构域的结合伴侣。我建议确定Rho-GEF结构域的功能意义，特别是通过确定其与RanBPM的相互作用的重要性，并在骨骼肌中检查这种相互作用。本研究将通过酵母双杂交实验、腺病毒的体内外转染以及生化和免疫学实验来实现这一目的。

DESCRIPTION (provided by applicant): Skeletal muscle is an highly organized structure composed of repeating contractile units known as sarcomeres. During embryonic development, sarcomeres are assembled and organized to form myofibrils. Defects in the proteins that form the sarcomeres and the cytoskeleton that supports the contractile apparatus can lead to muscular dystrophies. The signaling pathways that lead to gene transcription in normal development of myofibrils during embryogenesis and early postnatal life are thought to be the same as those that lead to gene transcription in physiological and pathological hypertrophic states in adult muscle. Obscurin, a recently discovered giant protein in skeletal muscle, contains a signaling domain, the Rho-GEF domain, which is likely to be involved in myofibrillogenesis. I have discovered that a Ran binding protein, RanBPM is a binding partner of the Rho-GEF domain of obscurin. I propose to determine the functional significance of the Rho-GEF domain, specifically by determining the importance of its interaction with RanBPM and examining this interaction in skeletal muscle. I will achieve this by using the yeast two hybrid assay, adenoviral transfections in vitro and in vivo, and biochemical and immunological experiments.