Molecular Regulation of Human iNOS by Phosphorylation

描述（由申请人提供）：诱导型一氧化氮合酶（iNOS）过度产生一氧化氮（NO）与包括气道肺炎在内的几种疾病的发病机制有关。 本研究的总体目标是了解iNOS的细胞周转的翻译后机制，从而为未来旨在控制NO合成的研究奠定基础。 我们的初步数据表明，诱导型一氧化氮合酶是受调节的磷酸化之前，其泛素化。 我们建议测试以下假设：A）连接泛素和iNOS的特异性泛素连接酶优先与磷酸化的iNOS结合。 因此，特定iNOS残基的磷酸化对于iNOS泛素化和降解至关重要。 B）细胞通过维持由细胞因子调节的iNOS更新的稳健速率来维持对NO合成的严格控制。 为了验证这些假设，我们提出了以下具体目的的研究：目的1：阐明磷酸化在iNOS周转中的作用并确定特定的磷酸化残基;目的2：iNOS周转率和调节它的细胞因子的表征。拟议研究的合理性在于，一旦了解了这些机制，可以设计治疗策略来改变这些途径并调节iNOS周转。

DESCRIPTION (provided by applicant): Overproduction of nitric oxide (NO) by inducible nitric oxide synthase (iNOS) has been implicated in the pathogenesis of several diseases including airway lung inflammation. The overall objective of this proposal is to understand the posttranslational mechanisms of cellular turnover of iNOS and thus lay the groundwork for future studies aiming at controlling NO synthesis. Our preliminary data suggest that iNOS is subject to regulation by phosphorylation precedes its ubiquitination. We propose to test the following hypotheses: A) The specific ubiquitin ligase that links ubiquitin to iNOS binds preferentially to phosphorylated iNOS. Thus phosphorylation of specific iNOS residue(s) is critical for iNOS ubiquitination and degraqdation. B) Cells maintain a tight control over NO synthesis by maintaining a robust rate of iNOS turnover that is modulated by cellular factors. To test these hypotheses we propose studies with the following Specific Aims; Aim 1: Elucidation of the role of phosphorylation in iNOS turnover and determining specific phosporylated residues; Aim 2: Characterization of the rate of iNOS turnover and cellular factors that modulate it. The rational for the proposed studies is that once these mechanisms are understood, therapeutic strategies can be designed to alter these pathways and modulate iNOS turnover.