Cytoskeletal linking proteins in renal epithelial cell function

肾上皮细胞功能中的细胞骨架连接蛋白

• 批准号: 7900989
• 负责人: R. BRIAN DOCTOR
• 金额: $ 35.95万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-01 至 2013-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7900989
• 关键词: Affect; Animal Model; Animals; Apical; Automobile Driving; Bilirubin; Binding; Biochemical; Biochemistry; Biological Assay; Blood Vessels; Cardiovascular Diseases; Carrier Proteins; Cell model; Cell physiology; Cells; Chloride Channels; Chronic; Chronic Idiopathic Jaundice; Cystic Fibrosis; Cystic Fibrosis Transmembrane Conductance Regulator; Deformity; Deposition; Disease; Dynamin; Endocytosis; Endosomes; Epithelial Cells; Epithelium; Equilibrium; Event; Excretory function; Fluorescence Microscopy; Foundations; Goals; Health Status; Homeostasis; In Vitro; Inorganic Phosphate Transporter; Ion Transport; Ions; Kidney; Link; Liquid substance; Liver; Measures; Medical; Membrane; Membrane Microdomains; Membrane Proteins; Membrane Transport Proteins; Modification; Molecular; Molecular Target; Movement; Organ; Pathway interactions; Phosphoric Monoester Hydrolases; Phosphorylation; Phosphotransferases; Physiological; Physiology; Play; Property; Protein Binding; Proteins; Proximal Kidney Tubules; Recovery; Regulation; Research Personnel; Role; Salts; Serous Membrane; Serum; Site; Sodium Chloride; Stimulus; Techniques; Tertiary Protein Structure; Testing; Tooth structure; Water; apical membrane; base; bone; cellular microvillus; genetic regulatory protein; human EMS1 protein; in vivo Model; inorganic phosphate; insight; link protein; novel; novel therapeutics; protein distribution; protein protein interaction; public health relevance; response; sodium phosphate; sodium-hydrogen exchanger 3; solute; symporter

DESCRIPTION (provided by applicant): In renal proximal tubule (PT) cells, the pivotal event in serum phosphate regulation is the insertion, retention and recovery of the sodium-phosphate 2a (NaPiIIa) co-transporter at the apical membrane. NaPiIIa activity is influence by its direct interaction with a number of distinct PDZ proteins, including EBP50 and PDZK1. These proteins appear to influence the delivery and retention of NaPiIIa in the apical membrane. More recently, a novel PDZ protein, Shank2E, was implicated in regulating NaPiIIa. Already known to bind endocytic proteins (e.g. dynamin, cortactin), Shank2E binds NaPiIIa and redistribute with NaPiIIa into the cell interior when NaPiIIa was endocytosed from the apical membrane. Consequently, the following proposal will test the hypothesis that Shank2E coordinates the endocytosis of NaPiIIa in a regulated manner. To this end, the proposed studies will (1) define the regulated protein-protein interactions between Shank2E and NaPiIIaassociated proteins, (2) determine the role of Shank2E in moderating NaPiIIa activity in proximal tubule cell models and (3) demonstrate the role of Shank2E in NaPiIIa regulation in whole animal models. Results from these studies will make important advances on three fronts. At the molecular level, the studies will determine how modifications in Shank2E-centered protein-protein interactions with other PDZ domain proteins and NaPiIIa are coordinately regulated. At the cellular and organ level, the studies will elucidate how these coordinately regulated interactions result in Shank2E directing the endocytic recovery of NaPiIIa in response to physiologic stimuli. Finally, these results may provide mechanistic insight into phosphatemic diseases and direct the genesis of novel therapeutic strategies. PUBLIC HEALTH RELEVANCE: The broad goal of the proposed studies is to better understand how the body regulates the movement of salts and water in and out of the body. The kidney is the central organ involved in maintaining salt and water balance in the body. The balance of phosphate by the kidney is essential for maintaining the health status of the body. Chronic decreases of phosphate levels can result in weaknesses and deformities in bones and teeth. Alternatively, even modest increases in phosphate levels can result in vascular deposits and cardiovascular disease. The pivotal event in regulating the balance of phosphate in the body is the activity level of a phosphate transport protein in the kidney. The proposed studies seek to discover and define how a recently identified protein in the kidney (termed Shank2E) is capable of turning down the activity of the phosphate transport protein. Interestingly, the Shank2E protein also binds other key transport proteins. These include a chloride channel that is linked to Cystic Fibrosis and a bilirubin transport protein in the liver that is linked to Dubin-Johnson Syndrome. By discovering how Shank2E functions to regulate these proteins the findings elucidate how the body maintains itself under normal conditions, how changes in these proteins might give rise to specific diseases and how researchers might take advantage of these regulated mechanisms to develop medical therapies to treat these diseases.

描述（由申请方提供）：在肾近端小管（PT）细胞中，血清磷酸盐调节的关键事件是磷酸钠2a（NaPIIIa）协同转运蛋白在顶膜的插入、保留和恢复。NaPiIIa活性受其与许多不同PDZ蛋白（包括EBP 50和PDZK 1）的直接相互作用的影响。这些蛋白质似乎影响NaPIIIa在顶膜中的递送和保留。最近，一种新的PDZ蛋白，Shank 2 E，涉及调节NaPiIIa。已知Shank 2 E结合内吞蛋白（例如发动蛋白、coronin），Shank 2 E结合NaPilla，并在NaPilla从顶膜内吞时与NaPilla一起重新分布到细胞内部。因此，以下提议将检验Shank 2 E以调节的方式协调NaPiIIa的内吞作用的假设。为此，拟议的研究将（1）确定Shank 2 E和NaPIIIa相关蛋白之间的调节蛋白质-蛋白质相互作用，（2）确定Shank 2 E在近端小管细胞模型中调节NaPIIIa活性的作用，（3）证明Shank 2 E在整个动物模型中调节NaPIIIa的作用。这些研究的结果将在三个方面取得重要进展。在分子水平上，这些研究将确定以Shank 2 E为中心的蛋白质-蛋白质相互作用与其他PDZ结构域蛋白质和NaPiIIa的修饰是如何协调调节的。在细胞和器官水平上，这些研究将阐明这些协调调节的相互作用如何导致Shank 2 E指导NaPIIa响应生理刺激的内吞恢复。最后，这些结果可能会提供机制的见解磷血症疾病和指导新的治疗策略的起源。公共卫生关系：拟议研究的广泛目标是更好地了解身体如何调节盐和水进出身体的运动。肾脏是维持体内盐和水平衡的中心器官。肾脏的磷酸盐平衡对于维持身体的健康状态至关重要。磷酸盐水平的慢性下降会导致骨骼和牙齿的虚弱和畸形。或者，即使磷酸盐水平适度增加也会导致血管沉积和心血管疾病。调节体内磷酸盐平衡的关键事件是肾脏中磷酸盐转运蛋白的活性水平。拟议的研究旨在发现和定义肾脏中最近发现的蛋白质（称为Shank 2 E）如何能够降低磷酸盐转运蛋白的活性。有趣的是，Shank 2 E蛋白还结合其他关键的转运蛋白。这些包括与囊性纤维化有关的氯离子通道和与Dubin-Johnson综合征有关的肝脏中的胆红素转运蛋白。通过发现Shank 2 E如何调节这些蛋白质，研究结果阐明了身体如何在正常条件下维持自身，这些蛋白质的变化如何引起特定疾病，以及研究人员如何利用这些调节机制来开发治疗这些疾病的医学疗法。