Mechanisms of Gap Junction Regulation

间隙连接调节机制

• 批准号: 7876874
• 负责人: PAUL L SORGEN
• 金额: $ 22.89万
• 依托单位: UNIVERSITY OF NEBRASKA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-06-01 至 2011-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7876874
• 关键词: Affect; Affinity; Area; Binding; Biological Models; Brain; Cardiac; Cataract; Cells; Charcot-Marie-Tooth Disease; Communication; Complex; Congenital Heart Defects; Connexin 43; Connexins; Connexon; Coupling; Cytoplasm; Cytoplasmic Tail; DNA Sequence Rearrangement; Defect; Development; Dimerization; Disease; Dissociation; Event; Gap Junctions; Genes; Goals; Heart; Homeostasis; Human; Inborn Genetic Diseases; Individual; Infarction; Inherited; Injury; Integral Membrane Protein; Ion Exchange; Ischemia; Lead; Link; Malignant - descriptor; Mediating; Metabolic; Modification; Molecular; Molecular Conformation; Mus; Mutation; Myocardial Ischemia; Organ; Pathway interactions; Phosphorylation; Process; Property; Protein Isoforms; Proteins; Regulation; Research; Research Personnel; Role; SH3 Domains; SRC gene; Scaffolding Protein; Signal Transduction; Site; Solvents; Structure; System; Testing; Therapeutic; Tight Junctions; Tissue Preservation; Tissues; Ventricular Arrhythmia; Work; base; cell growth regulation; deafness; design; dimer; gap junction channel; genetic manipulation; intercellular communication; intermolecular interaction; nervous system disorder; particle; programs; receptor; response; skin disorder; small molecule

DESCRIPTION (provided by applicant): The long term goal of our work is to gain a structural and functional understanding of the mechanisms of gap junction regulation. Gap junctions, formed of proteins called connexins (Cxs), provide an intercellular pathway for the propagation of electrical/molecular signals, which are necessary for cellular differentiation, metabolic homeostasis, and in excitable tissue, electrical coupling. This type of communication permits individual cell events to synchronize into the functional response of an entire organ. Defects in human Cx genes that affect cell coupling are associated with a variety of inherited disorders (e.g. Charcot-Marie-Tooth disease and hereditary non-syndromic deafness). Genetic manipulations in mice have demonstrated the functional importance of Cxs in a variety of organs. Moreover, not only the presence but also the proper regulation of gap junctions is critical for homeostasis. For example, intracellular acidification leads to closure of gap junctions in all native tissues and exogenous expression systems tested. The study of pH-dependent regulation of gap junctions becomes even more relevant given that intracellular acidification is a major consequence of tissue ischemia. Acidification-induced uncoupling has an impact on the preservation of tissue surrounding the ischemic area. Therefore, we have chosen Cx43, the most widely expressed junction protein in the heart, brain, and other tissues, as our model system to study the structural regulation of Cxs. Our objective is to apply biophysical approaches to investigate intra-and intermolecular interactions that define the structural regulation of Cx43 during pH gating. We hypothesize that the Cx43 carboxyl terminal domain (CT) acts as a gating "particle" that, under the appropriate conditions (e.g. intracellular acidification or phosphorylation), binds to a "receptor" (i.e. Cx43 cytoplasmic loop; CL) affiliated with the pore and closes the channel. The following Specific Aims are proposed to investigate this concept: 1) To establish how the CT interacts with molecular partners that are involved in gap junction regulation; 2) To assess the structural effect of pH on the CT and CL domains; 3) To characterize cytoplasmic domain interactions between Cx isoforms. These Aims are designed to identify the functional consequences resulting from CT interactions with molecular partners and the CL in an effort to develop site-directed, specific modulators of gap junction communication with potential implications in therapeutic treatment of disease and ischemic injury.

描述（由申请人提供）：我们工作的长期目标是获得对间隙连接调节机制的结构和功能理解。间隙连接由称为连接蛋白 (Cxs) 的蛋白质形成，为电/分子信号的传播提供细胞间通路，这对于细胞分化、代谢稳态以及可兴奋组织中的电耦合是必需的。这种类型的通讯允许单个细胞事件同步到整个器官的功能反应中。影响细胞耦合的人类 Cx 基因缺陷与多种遗传性疾病有关（例如夏科-玛丽-图斯病和遗传性非综合征性耳聋）。对小鼠的基因操作已经证明了 Cxs 在多种器官中的功能重要性。此外，间隙连接的存在和适当的调节对于体内平衡都至关重要。例如，细胞内酸化导致所有天然组织和测试的外源表达系统中间隙连接的闭合。鉴于细胞内酸化是组织缺血的主要后果，对间隙连接的 pH 依赖性调节的研究变得更加相关。酸化引起的解偶联对缺血区域周围组织的保存有影响。因此，我们选择心脏、大脑和其他组织中表达最广泛的连接蛋白Cx43作为我们的模型系统来研究Cxs的结构调控。我们的目标是应用生物物理学方法来研究分子内和分子间相互作用，从而定义 pH 门控过程中 Cx43 的结构调节。我们假设 Cx43 羧基末端结构域 (CT) 作为门控“颗粒”，在适当的条件下（例如细胞内酸化或磷酸化），与附属于孔的“受体”（即 Cx43 细胞质环；CL）结合并关闭通道。提出以下具体目标来研究这一概念：1）确定 CT 如何与参与间隙连接调节的分子伙伴相互作用； 2) 评估pH对CT和CL结构域的结构影响； 3) 表征 Cx 同工型之间的细胞质结构域相互作用。这些目标旨在确定 CT 与分子伙伴和 CL 相互作用所产生的功能后果，努力开发间隙连接通讯的定点特异性调节剂，对疾病和缺血性损伤的治疗具有潜在影响。