Calcium desensitization in Smooth Muscle

平滑肌在多种生理过程中起着重要作用，尽管平滑肌细胞在许多生理过程中起着重要作用。 每个平滑肌的基本功能是相同的，收缩和舒张，机械性能和 对激素、神经递质和药物的反应在平滑肌类型之间变化很大。 决定平滑肌收缩特性的因素包括质膜性质， 信号转导蛋白的比例和互补，收缩装置本身的组成。 这些成分的正常混合物中的改变被认为是几种蛋白质的分子基础的基础。 涉及平滑肌的人类疾病包括高血压、支气管痉挛、性功能障碍 胃肠道疾病和青光眼。我们的假设是，通过研究 哪种平滑肌对刺激有正常反应将导致更有选择性的治疗 这些紊乱。最近完成的人类和小鼠基因组结合先进的 质谱技术为探测细胞中的信号转导途径提供了新的机会。 在这项提案中，我们将采用蛋白质组学，肌肉生理学，分子生物学， 免疫组织化学和小鼠遗传学，以确定cGMP 通过激活环GMP依赖性蛋白激酶（PKG）调节平滑肌松弛。 各种平滑肌的磷酸化蛋白质组的检查鉴定了一个不同的早期蛋白质亚群， PKG的目标。在小鼠和人类基因组中发现了几个，包括CHASM，一种新的 一种蛋白质，含有一种以前未鉴定的基序，在平滑肌细胞的smoothelin家族中高度保守 肌肉特异性蛋白质当添加到透化平滑肌中时，CHASM会导致钙 以磷酸化依赖的方式脱敏和松弛。层序分化程度 在CHASM基序区域内插入的非保守氨基酸表明CHASM和 平滑肌蛋白可能是平滑肌特异性蛋白质大家族的一部分， 介导cGMP/PKG的作用。为了直接验证这一假设，我们删除了CHASM基因， 获得CHASM敲除小鼠。

Smooth muscle plays an essential role in a wide variety of physiological processes, and although the basic function of every smooth muscle is the same, to contract and relax, the mechanical properties and responsiveness to hormones, neurotransmitters and drugs varies greatly between smooth muscle types. Factors that dictate the contractile characteristics of smooth muscle include plasma membrane properties, ratio and compliment of signal transducing proteins, the composition of the contractile apparatus itself. Alteration in the normal blend of these components is thought to underlie the molecular basis of several human diseases that involve smooth muscle including hypertension, bronco spasm, sexual dysfunction, gastrointestinal disorders and glaucoma. It is our hypothesis that by studying the molecular processes by which individual smooth muscles normally respond to stimulation will lead to more selective therapies to treat these disorders. The recent completion of the human and mouse genomes in combination with advanced techniques in mass spectrometry affords new opportunities for probing signal transduction pathways in cells. In this proposal we will employ a unique combination of proteomics, muscle physiology, molecular biology, immuno-histochemistry and mouse genetics to determine the molecular mechanisms by which cGMP through the activation of cyclic GMP dependant protein kinase (PKG) regulates smooth muscle relaxation. Examination of phosphoproteomes of various smooth muscles identified a distinct subset of early protein targets for PKG. Several were identified in the mouse and human genome, including CHASM, a novel protein containing a previously unidentified motif that is highly conserved in the smoothelin family of smooth muscle specific proteins. When added to permeabilized smooth muscles, CHASM causes calcium desensitization and relaxation in a phosphorylation dependant manner. The degree of sequence divergence of the intervening non-conserved amino acids within the CHASM motif region suggests that CHASM and the smoothelins may be part of a larger family of smooth muscle specific proteins that are important in the mediating the actions of cGMP/PKG. To directly test this hypothesis we have deleted the CHASM gene and obtained CHASM null mice.