Cell Signaling by Protease-activated G Protein-coupled Receptors

摘要 我们NIGMS支持的研究计划的总体目标是勾勒出监管 蛋白水解酶激活受体-1(PAR1)及其亲缘家族调控信号的机制 会员在正常生理和疾病方面。我们的努力导致了泛素化的发现 PAR1促进p38丝裂原活化蛋白激酶(MAPK)内含体信号转导 溶酶体降解。泛素化的P2Y1受体的功能类似。这项工作进一步揭示了 PAR1泛素化在p38介导的内皮屏障破坏中的独特作用。然后我们 发现了PAR1的一条新的溶酶体途径，该途径也与其他G蛋白偶联受体相关 (GPCRs)。与传统观点相反，我们发现某些GPCRs和规范的泛素化 泛素结合的ESCRT不是受体溶酶体降解所必需的。然后我们确定了ALG- 相互作用蛋白(Alix)和arrestin相关结构域包含蛋白-3(ARRDC3)是 GPCR型溶酶体分选。Alix依赖的途径绕过了GPCR的要求 泛素化，不同于运输所需的规范内体分选复合体 (ESCRT)溶酶体途径。Alix和ARRDC3通路在癌症中似乎也存在调节失调。 拟议研究的中心前提是泛素化提供了新的和多样化的机制。 用于GPCR生物学的调节。透彻了解关键监管机构和 泛素化的介体调节gpr信号和贩运对于理解是必不可少的 疾病中的失调机制和确定新的药物靶点。拟议的研究将允许 我的研究小组对我们开创的新概念有一个透彻的理解-- GPCRs的泛素化在正常生理中调节信号，在疾病中被破坏。我们的研究 提出了许多令人兴奋的问题，并将继续进行最具变革性的研究。P38 MAPK介导炎症，但目前尚不清楚GPCR如何激活泛素驱动的p38 信号促进内皮屏障通透性，这是炎症的一个关键特征，这一点将被确定。 对GPCR内体信号是如何调控的了解有限，这是一个挑战。因此， 我们将定义调节GPCR激活的、泛素驱动的p38内体信号的机制。 一些GPCR通过Alix依赖的途径进行排序，而不是标准的ESCRT，然而， 将GPCRs分离成不同的溶酶体途径的关键步骤尚不清楚，将予以描述。 ARRCD3在乳腺癌中的表达缺失或抑制，但目前尚不清楚ARRDC3是如何表达的 影响PAR1功能或促进癌症进展，并将进行检查。我们装备齐全 以我的实验室的专业知识和经验来进行这些研究，描绘出 泛素化在正常生理和疾病中调节gpr信号和运输。

Summary The overall goals of our NIGMS-supported research program have been to delineate the regulatory mechanisms that control signaling by protease-activated receptor-1 (PAR1) and closely-related family members in normal physiology and disease. Our efforts have led to the discovery that ubiquitination of PAR1 promotes p38 mitogen-activated protein kinase (MAPK) signaling from endosomes and not lysosomal degradation. Ubiquitination of the P2Y1 receptor functions similarly. This work further revealed a distinct function for ubiquitination of PAR1 in p38-mediated endothelial barrier disruption. We then discovered a novel lysosomal pathway for PAR1 that is also relevant to other G protein-coupled receptors (GPCRs). Contrary to conventional view, we found that ubiquitination of certain GPCRs and canonical ubiquitin-binding ESCRTs are not required for receptor lysosomal degradation. We then identified ALG- interacting protein (ALIX) and arrestin-related domain containing protein-3 (ARRDC3) as key mediators of GPCR lysosomal sorting. The ALIX-dependent pathway bypasses the requirement for GPCR ubiquitination and is distinct from the canonical endosomal sorting complexes required for transport (ESCRT) lysosomal pathway. The ALIX and ARRDC3 pathway also appears to be dysregulated in cancer. The central premise for the proposed studies is that ubiquitination offers novel and diverse mechanisms for regulation of GPCR biology. A thorough understanding of the mechanism by which key regulators and mediators of ubiquitination regulate GPCR signaling and trafficking is essential for understanding dysregulated mechanisms in disease and for identifying new drug targets. The proposed studies will allow my research group to grasp a thorough understanding of novel concepts that we pioneered - that ubiquitination of GPCRs regulates signaling in normal physiology and is disrupted in disease. Our studies have raised many exciting questions and the most transformative research will be pursued. The p38 MAPK mediates inflammation, however it is not known how GPCR-activated, ubiquitin-driven p38 signaling promotes endothelial barrier permeability, a key feature of inflammation, and will be determined. There is a limited understanding of how GPCR endosomal signaling is regulated and is a challenge. Thus, we will define the mechanisms that regulate GPCR-activated, ubiquitin-driven p38 endosomal signaling. Several GPCRs sort through the ALIX-dependent pathway rather than canonical ESCRT, however, the key steps that segregate GPCRs into distinct lysosomal pathways are not known and will be delineated. ARRCD3 expression is either lost or suppressed in breast cancer, however it is not clear how ARRDC3 impacts PAR1 function or contributes to cancer progression and will be examined. We are well equipped to perform these studies given my laboratory's expertise and experience delineating the function of ubiquitination in regulation of GPCR signaling and trafficking in normal physiology and disease.