TGF-β signaling and regulation: Elucidating molecular mechanisms and pathogenic functions of the ‘co-receptor’ Cripto-1 and the receptor BMPRII

TGF-β 信号传导和调节：阐明 辅助受体 Cripto-1 和受体 BMPRII 的分子机制和致病功能

• 批准号: 10078866
• 负责人: Erik Matthias Martinez Hackert
• 金额: $ 30.52万
• 依托单位: MICHIGAN STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10078866
• 关键词: Affinity; Antibodies; Binding; Binding Sites; Biochemistry; Blood Vessels; CFC1 gene; Cell Differentiation process; Cell Proliferation; Cell physiology; Cell surface; Cells; Cellular biology; Chemosensitization; Complex; Crystallization; Development; Disease; EGF gene; Endosomes; Epitopes; Family; Family member; Goals; Health; Homeostasis; Homologous Gene; Human; Lead; Ligand Binding; Ligands; Link; Lung; Malignant Neoplasms; Mammalian Cell; Mediating; Membrane; Modality; Molecular; Mutagenesis; Mutation; Normal Cell; Oncogenic; Pathogenicity; Pathologic; Pathologic Processes; Pathway interactions; Phenotype; Physiological; Physiological Processes; Protein Family; Regulation; Role; Signal Transduction; Specific qualifier value; Specificity; Structure; Surface; System; Therapeutic; Tissues; Transforming Growth Factor beta Receptors; Transforming Growth Factors; Validation; X-Ray Crystallography; base; bone morphogenetic protein receptors; cancer cell; cell motility; design; drug discovery; hypertension treatment; inhibitor/antagonist; novel therapeutics; prevent; pulmonary arterial hypertension; receptor; receptor binding; structural biology; therapeutic development; therapeutic target; tool; transcription factor; tumor progression; tumorigenesis

PROJECT SUMMARY TGF-β family proteins are critically important for human health. They regulate differentiation, proliferation and homeostasis in normal cell physiology, but mutations or abnormal expression are associated with devastating diseases, including cancers, and Pulmonary Arterial Hypertension (PAH). Discovering therapeutics that target TGF-β family proteins is an urgent priority and will have a great impact on human health. However, identifying therapeutics has been difficult, because the physiological and pathological activities of TGF-β family proteins are poorly defined. A profound molecular understanding of TGF-β family action is essential to overcome these obstacles. Thus, the overarching goal of the lab is to determine how TGF-β family signaling is regulated and to link our findings with physiological and pathological processes. We blend tools of structural biology, biochemistry and cell biology. Here, we have two aims. In Aim 1 we will validate the newly established mechanism of ligand recognition by Cripto-1 family co-receptors and examine the roles of membrane-anchored and soluble Cripto-1 in cancers. Cripto-1 is a membrane-anchored, EGF-CFC family `co-receptor' that promotes tumor progression. It can both potentiate and inhibit TGF-β family signaling. But how Cripto-1 mediates these opposing activities is not clear. Our recent studies suggest a mechanism. Cripto-1 blocks binding of TGF-β family ligands to receptors. Thus, a soluble form inhibited signaling. But membrane-anchored Cripto-1 potentiated signaling and promoted tumorigenesis. We hypothesize that membrane-anchored Cripto-1 captures ligands at the cell surface and directs ligands into endosomes for signal potentiation and oncogenic activation. Elucidating the Cripto-1/EGF-CFC mechanism of ligand capture and oncogenic activation could reveal epitopes and modalities to target Cripto-1 in cancers. In Aim 2 we will identify the ligand binding determinants of the `type II' TGF-β family receptor BMPRII and establish functional consequences of ligand binding-competition for BMPRII mediated signaling and PAH. TGF-β family signals are transduced via SMAD transcription factors. In PAH, BMPRII mediated SMAD1/5/8 signaling is reduced. Just how is not understood. Our recent findings offer a clue. We discovered that ligands regulated by Cripto-1 or its homolog Cryptic bind BMPRII with high affinity. Until now, BMPRII was believed to be a low affinity receptor for BMPs, a subclass of TGF-β family ligands. We also found that high affinity ligands inhibit BMP dependent SMAD1/5/8 signaling by competing for receptor binding. We hypothesize that Cripto-1/Cryptic ligands suppress BMPRII mediated SMAD1/5/8 signaling in PAH by competing with BMPs for BMPRII binding. Demonstrating that binding- competition promotes PAH phenotypes and identifying epitopes on ligands that contact BMPRII could lead to development of inhibitors that prevent high affinity BMPRII ligands from competing with low affinity BMPs, and thus could help restore BMPRII mediated SMAD1/5/8 signaling in PAH. Successful completion of these studies could help open new avenues for targeting Cripto-1 in cancers and for restoring BMPRII function in PAH.

项目概要 TGF-β 家族蛋白对人类健康至关重要。 正常细胞生理学中的稳态，但突变或异常表达与破坏性相关 发现针对癌症和肺动脉高压 (PAH) 的治疗方法。 TGF-β家族蛋白是当务之急，将对人类健康产生巨大影响。 治疗一直很困难，因为 TGF-β 家族蛋白的生理和病理活性 对 TGF-β 家族作用的深刻分子理解对于克服这些问题至关重要。 因此，该实验室的首要目标是确定 TGF-β 家族信号传导是如何调节的。 我们将结构生物学的工具与我们的发现联系起来， 在这里，我们有两个目标，即目标 1，我们将验证新建立的目标。 Cripto-1 家族共受体的配体识别机制并检查膜锚定的作用 癌症中的可溶性 Cripto-1 是一种膜锚定的 EGF-CFC 家族“辅助受体”。 它可以增强和抑制 TGF-β 家族信号传导，但 Cripto-1 的作用如何？ 我们最近的研究表明 Cripto-1 阻断的机制尚不清楚。 TGF-β家族配体与受体的结合因此，可溶形式抑制信号传导，但膜锚定。 Cripto-1 增强了信号传导并促进了肿瘤发生。 在细胞表面捕获配体并将配体引导至核内体以增强信号并致癌 阐明 Cripto-1/EGF-CFC 的配体捕获和致癌激活机制。 揭示癌症中针对 Cripto-1 的表位和模式 在目标 2 中，我们将鉴定配体结合。 “II 型”TGF-β 家族受体 BMPRII 的决定因素并确定配体的功能后果 BMPRII 介导的信号传导和 TGF-β 家族信号的结合竞争通过 SMAD 转导。 在 PAH 中，BMPRII 介导的 SMAD1/5/8 信号传导如何减少尚不清楚。 我们最近的发现提供了一条线索，我们发现配体受 Cripto-1 或其同源物 Cryptic 结合调节。 具有高亲和力的 BMPRII 迄今为止，BMPRII 被认为是 BMP（BMP 的一个亚类）的低亲和力受体。 我们还发现高亲和力配体通过抑制 BMP 依赖性 SMAD1/5/8 信号传导。 我们认为 Cripto-1/Cryptic 配体会抑制 BMPRII 介导的受体结合。 PAH 中的 SMAD1/5/8 信号传导通过与 BMP 竞争 BMPRII 结合来证明。 竞争促进 PAH 表型，识别与 BMPRII 接触的配体上的表位可能导致 开发抑制剂，防止高亲和力 BMPRII 配体与低亲和力 BMP 竞争，以及 因此可以帮助恢复 PAH 中 BMPRII 介导的 SMAD1/5/8 信号传导。这些研究的成功完成。 可能有助于开辟针对癌症中的 Cripto-1 和恢复 PAH 中的 BMPRII 功能的新途径。