Betal Integrin and Renal Tubulogenesis

β整合素和肾小管发生

• 批准号: 8668041
• 负责人: ROY ZENT
• 金额: $ 33.93万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-03-04 至 2016-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8668041
• 关键词: Adhesions; Adult; Affect; Binding; Binding Sites; Biochemical; Biological; Biological Assay; Biology; Case Study; Cells; Cytoplasmic Tail; Data; Defect; Development; Distal; Duct (organ) structure; Dysplasia; Epithelial; Etiology; Exhibits; Extracellular Matrix; Funding; Goals; In Vitro; Infant; Integrins; Kidney; Kidney Diseases; Kidney Failure; Knockout Mice; Knowledge; Ligand Binding; Mammals; Manuscripts; Mass Spectrum Analysis; Mediating; Membrane; Metanephric Diverticulum; Morphogenesis; Mus; Mutate; Mutation; Nephrons; Phenotype; Preparation; Process; Property; Protein Binding; Protein Binding Domain; Proteins; Renal tubule structure; Research; Role; Signal Transduction; Syndrome; System; Tail; Talin; Techniques; Testing; Transgenic Mice; dimer; in vivo; insight; migration; mouse development; mouse model; nephrogenesis; novel; programs; receptor; skin disorder

DESCRIPTION (provided by applicant): Integrins, the principal receptors that mediate cell-ECM interactions, are composed of heterodimeric transmembrane and subunits. The 18 and 8 subunits found in mammals combine in a restricted manner to form specific dimers with different ligand binding properties. 1, the most abundantly expressed integrin subunit in the kidney, binds at least 12 subunits. Its short cytoplasmic tail interacts with multiple intracellular molecules tht promote integrin- mediated adhesion, migration and signaling. The best defined of these proteins are talins and kindlins, which we and others showed are required for normal integrin function. These proteins bind to two canonical NPXY motifs found in all integrin cytoplasmic tails: talins to the membrane proximal and kindlins to the membrane distal motifs. In the last funding period, we utilized integrin beta1flox/flox mice to demonstrate that this integrin subunit s required for normal uretereic bud (UB) development, as deleting it using hoxb7cre mice resulted in severe abnormalities in branching morphogenesis. We further showed that mutating canonical NPXY motifs of the integrin 1 cytoplasmic tail also resulted in abnormal UB development. Kidneys with a Y/A mutation in both motifs (thus affecting binding of talins and kindlins) are severely dysmorphic and dysplastic, but have a significantly less severe branching defect than the UB integrin 1-null mice. Thus a key unanswered question in the field of integrin biology and kidney development is how the NPXY motifs regulate integrin function and whether they have distinct functions from each other. We propose to answer this question by testing the hypothesis that binding of talins and kindlins to specific NPYX motifs of the integrin 1 cytoplasmic tail differentially regulates integrin functions required for normal UB development. This hypothesis will be tested by the following three specific aims. 1) Determine if talin binding to the membrane proximal NPXY motif of the integrin 1 cytoplasmic tail is required for normal UB development. 2) Determine if kindlin binding to the membrane distal NPXY motif of the integrin 1 cytoplasmic tail is required for normal UB development and function. 3) Define the mechanisms whereby integrin 1 NPXY motif binding proteins regulate collecting duct cell branching morphogenesis. Completion of these aims will help define the fundamental mechanisms whereby 1 integrins regulate renal tubule formation in the context of UB development. This has implications for our understanding of both congenital renal hypoplasia/dysplasia syndromes and adult renal diseases as UB branching is a key determinant of nephron number.

描述（由申请人提供）：整合素是介导细胞-ECM相互作用的主要受体，由异二聚体跨膜和亚基组成。在哺乳动物中发现的 18 和 8 亚基以有限的方式结合形成具有不同配体结合特性的特异性二聚体。 1 是肾脏中表达最丰富的整合素亚基，至少结合 12 个亚基。其短的细胞质尾与多种细胞内分子相互作用，促进整合素介导的粘附、迁移和信号传导。这些蛋白质中最好的定义是 talins 和 kindlins，我们和其他人证明它们是正常整合素功能所必需的。这些蛋白质与所有整联蛋白细胞质尾部中发现的两个典型 NPXY 基序结合：近端膜的踝蛋白和远端膜基序的引体蛋白。在上一个资助期间，我们利用整合素 beta1flox/flox 小鼠来证明该整合素亚基是正常输尿管芽（UB）发育所必需的，因为使用 hoxb7cre 小鼠删除它会导致分支形态发生的严重异常。我们进一步表明，整合素 1 胞质尾部的典型 NPXY 基序的突变也会导致 UB 发育异常。两个基序均发生 Y/A 突变（从而影响 talins 和 kindlins 的结合）的肾脏具有严重的畸形和发育不良，但分支缺陷的严重程度明显低于 UB 整合素 1 缺失小鼠。因此，整合素生物学和肾脏发育领域中一个尚未解答的关键问题是NPXY基序如何调节整合素功能以及它们是否具有彼此不同的功能。我们建议通过测试以下假设来回答这个问题：talins 和 kindlins 与整合素 1 细胞质尾部的特定 NPYX 基序的结合差异调节正常 UB 发育所需的整合素功能。这一假设将通过以下三个具体目标进行检验。 1) 确定 talin 与整合素 1 胞质尾部近膜 NPXY 基序的结合是否是正常 UB 发育所必需的。 2) 确定正常的UB发育和功能是否需要kindlin与整合素1细胞质尾部的膜远端NPXY基序结合。 3）定义整合素1 NPXY基序结合蛋白调节集合管细胞分支形态发生的机制。完成这些目标将有助于确定 1 整合素在 UB 发育过程中调节肾小管形成的基本机制。这对我们理解先天性肾发育不全/发育不良综合征和成人肾脏疾病具有重要意义，因为 UB 分支是肾单位数量的关键决定因素。