Kinase mediated signaling in the rice defense response

水稻防御反应中激酶介导的信号传导

• 批准号: 7579941
• 负责人: PAMELA C RONALD
• 金额: $ 25.73万
• 依托单位: UNIVERSITY OF CALIFORNIA AT DAVIS
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-01-01 至 2010-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7579941
• 关键词: Affinity; Animals; Binding Proteins; Binding Sites; Cell Surface Receptors; Cell physiology; Cereals; Complex; Cytoplasmic Tail; Development; Disease; Disease Resistance; Environment; Event; Extracellular Domain; Family; Flagellin; Gene Targeting; Genes; Genetic Transcription; Health; Immune response; Immunity; Lead; Leucine-Rich Repeat; Mediating; Modeling; Molecular; Natural Immunity; Pathway interactions; Perception; Pesticides; Phosphoric Monoester Hydrolases; Phosphorylation; Phosphotransferases; Plants; Play; Process; Protein Dephosphorylation; Protein Kinase; Proteins; Regulation; Rice; Risk; Role; Signal Transduction; Signaling Protein; Specificity; Testing; base; defense response; disorder control; extracellular; in vivo; interest; pathogen; receptor; response

DESCRIPTION (provided by applicant): Perception of extracellular signals by cell surface receptors is of central importance to eukaryotic development and immunity. Many of these receptors possess intrinsic protein kinase activity in their cytoplasmic domains (RKs) and regulate transcription of target genes through phosphorylation and dephosphorylation events. Abnormal regulation can lead to a variety of diseases and it is therefore important to understand how RK specificity and function are controlled. In contrast to most protein kinases that are regulated by phosphorylation of the activation segment, a centrally located loop that sits close to the catalytic center, an emerging theme for some RKs is that the juxtamembrane (JM) domain plays a key regulatory role in their activation. In this case, residues in the JM domain perform both positive and negative regulatory functions. In their unphosphorylated state they repress catalytic activity and upon phosphorylation they serve as high affinity binding sites for downstream signaling proteins. Regulation of RK signaling through the JM domain is so far unique to only a few receptor families controlling important cellular processes and consequently there is great interest in exploring the molecular basis for this control. The rice XA21 gene, encoding a RK with leucine rich repeats (LRRs) in the extracellular domain, is a key recognition and signaling determinant in the innate immune response, a pathogen defense pathway widely conserved between plants and animals. XA21 is not autophosphorylated in the activation segment and at least four XA21 binding proteins (Xbs) require phosphorylated residues in the JM region for interaction. These include Xb10, encoding a putative transcriptional regulator and Xb15 encoding a PP2c phosphatase-like protein. Based on these results we hypothesize that the XA21 JM domain plays a key role in XA21 kinase-mediated signal transduction and that JM-binding protein's act as positive or negative regulators to control transcription of defense related genes. To further test this hypothesis we propose to: 1. Determine the role of Xb10 and Xb15 in Xa2'l -mediated and flagellin-activated defense responses. 2. Further characterize the XA21 JM domain, identify Xb kinase interaction domains and assess the role of XA21-dependent phosphorylation 3. Characterize the cellular interactions of XA2jl and Xbs and identify new components in the in vivo complexes.

描述（由申请人提供）：细胞表面受体对细胞外信号的感知对于真核发育和免疫至关重要。这些受体中的许多受体在其细胞质结构域（RKS）中具有内在的蛋白激酶活性，并通过磷酸化和去磷酸化事件调节靶基因的转录。异常调节会导致各种疾病，因此了解如何控制RK的特异性和功能。 与大多数受激活段磷酸化调节的蛋白激酶相比，激活段的磷酸化是一个位于中央的环路，位于催化中心附近，某些RKS的新兴主题是juxtammbrane（JM）结构域在其激活中起关键调节作用。在这种情况下，JM结构域中的残基同时执行正调控功能。在未磷酸化的状态下，它们抑制催化活性并在磷酸化时充当下游信号蛋白的高亲和力结合位点。到目前为止，通过JM域的调节RK信号传导仅是控制重要细胞过程的少数受体家族，因此对探索该对照的分子基础有极大的兴趣。 大米XA21基因在细胞外结构域中用富含亮氨酸的重复序列（LRR）编码RK，是先天免疫反应中的关键识别和信号传导决定因素，这是一种在植物和动物之间广泛保守的病原体防御途径。 XA21在激活段中未自磷酸化，至少四个XA21结合蛋白（XBS）需要JM区域中的磷酸化残基进行相互作用。这些包括XB10，编码推定的转录调节剂和编码PP2C磷酸酶样蛋白的XB15。 基于这些结果，我们假设XA21 JM结构域在XA21激酶介导的信号转导中起关键作用，并且JM结合蛋白的作用是控制防御相关基因转录的正或负调节剂。为了进一步检验这一假设，我们建议： 1。确定XB10和XB15在XA2'L介导的和鞭毛蛋白激活的防御反应中的作用。 2。进一步表征XA21 JM域，识别XB激酶相互作用域并评估XA21依赖性磷酸化的作用 3。表征XA2JL和XB的细胞相互作用，并识别体内复合物中的新成分。