COBRE: UNR: SIGNAL TRANSDUCTION PATHWAYS REGULATED BY CELL VOLUME

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。生理细胞体积的维持对细胞增殖、分化和存活至关重要。阴离子通道，特别是氯离子（Cl-）通道，参与其他重要的生理功能，包括维持心脏的节律周期和血管的肌肉张力。Cl-通道ClC-3是肺动脉平滑肌细胞（PASMCs）的主要体积调节剂，但其调节作用尚不明确。本研究的主要目标是通过解决以下具体目标，确定各向异性细胞环境中调节ClC-3的基本细胞内机制：(1)验证蛋白激酶通过磷酸化调节体积敏感的外向整流阴离子通道(VSOAC)/ClC-3的假设。生化和分子方法将用于pasmc和NIH 3T3细胞的实验，以确定ClC-3受其n端（NT）和/或c端（CT）的磷酸化调节，并确定体外和体内磷酸化ClC-3的蛋白激酶。(2)验证血清和糖皮质激素依赖性激酶（SGK）通过间接磷酸化和/或泛素化调节VSOAC/ClC-3的假设。这一目标将涉及实验，以测试低渗肿胀介导的SGK激活导致目前未知的中间激酶激活的可能性，或通过NIH 3T3细胞和犬pasmc中泛素化降低和ClC-3膜表达增加的可能性。(3)验证皮层下肌动蛋白和肌动蛋白结合蛋白与VSOAC/ClC-3通道相互作用并参与其活化的假说。这一目标将包括评估细胞质ClC-3末端与肌动蛋白丝和肌动蛋白结合蛋白的结合能力的实验，以确定参与该关联的ClC-3结构域，并验证抑制这种相互作用会干扰ClC-3激活的假设。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Maintenance of physiological cell volume is crucial for cell proliferation, differentiation and survival. Anion channels, and particularly chloride (Cl-) channels, participate in other important physiological functions including maintenance of the rhythmic cycle of the heart and the muscle tone of blood vessels. The Cl- channel ClC-3 is a major volume regulator in pulmonary artery smooth muscle cells (PASMCs), however its regulation is undefined. The major goal of the present proposal is to define the fundamental intracellular mechanisms regulating ClC-3 in anisotonic cell environment, by addressing the following specific aims: (1) Test the hypothesis that protein kinases regulate the volume-sensitive outwardly rectifying anion channel (VSOAC)/ClC-3 by phosphorylation. Biochemical and molecular approaches will be utilized in experiments with PASMCs and NIH 3T3 cells to establish that ClC-3 is regulated by phosphorylation of its N-terminus (NT) and/or C-terminus (CT), and to identify protein kinases that phosphorylate ClC-3 in vitro and in vivo. (2) Test the hypothesis that the serum and glucocorticoid-dependent kinase (SGK) regulates VSOAC/ClC-3 by indirect phosphorylation and/or ubiquitination. This aim will involve experiments to test the possibility that hypotonic swelling-mediated activation of SGK leads to activation of a currently unknown intermediate kinase, or by decreased ubiquitination and increased membrane expression of ClC-3 in NIH 3T3 cells and canine PASMCs. (3) Test the hypothesis that subcortical actin and actin-binding proteins interact with VSOAC/ClC-3 channel and contribute to its activation. This aim will include experiments to assess the binding capacity of the cytosolic ClC-3 termini with actin filaments and actin-binding proteins, to identify ClC-3 domains involved in the association, and to test the hypothesis that inhibition of this interaction interferes with the activation of ClC-3.