Growth Hormone Receptor Dimerization & Disulfide Linkage

生长激素受体二聚化

• 批准号: 8231522
• 负责人: Stuart J Frank
• 金额: $ 31.86万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-06-01 至 2015-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8231522
• 关键词: Address; Affect; Aggressive behavior; Anabolism; Animal Model; Animals; Anterior Pituitary Gland; Antibodies; Behavior; Binding; Breast; Breast Cancer Cell; Cell Culture System; Cell surface; Complex; Cytokine Receptors; Development; Dimerization; Disease; Disulfide Linkage; Down-Regulation; Endocrine; Endometrial Carcinoma; Extracellular Domain; Fab Immunoglobulins; Growth; Growth Hormone Receptor; Hormone Antagonists; Human; Incidence; JAK2 gene; Knowledge; Laboratories; Learning; Ligands; Malignant Neoplasms; Malignant neoplasm of prostate; Mediating; Membrane Glycoproteins; Metabolism; Molecular Conformation; Monoclonal Antibodies; Mus; Outcome; Pathway interactions; Physiological; Physiology; Process; Prolactin Receptor; Property; Prostate; Protein Tyrosine Kinase; Reagent; Receptor Activation; Rodent; Role; STAT5A gene; Signal Transduction; Somatotropin; Somatropin; Surface; T47D; Therapeutic; Therapeutic Intervention; Thinking; Transmembrane Domain; Tyrosine; Vertebrates; Work; autocrine; base; cancer cell; cancer therapy; dimer; hormone sensitivity; human GHR protein; in vivo; insight; malignant breast neoplasm; member; novel; peptide hormone; postnatal; public health relevance; receptor; receptor expression; stoichiometry; tool; trafficking; tumorigenesis

DESCRIPTION (provided by applicant): Growth hormone (GH), derived largely from the anterior pituitary, regulates postnatal growth and metabolism in vertebrates in an endocrine fashion. Recent studies also suggest roles for autocrine-derived GH and for an intact GH axis in formation and behavior of cancers in animals. GH receptor (GHR) is a cell surface glycoprotein cytokine receptor superfamily member that binds GH in its extracellular domain (ECD) and activates signaling via its intracellular domain's (ICD) interaction with the JAK2 tyrosine kinase. Our recent studies of mechanisms regulating GHR availability and activation reveal exciting insights, including: 1) JAK2 association influences GHR surface presentation, stability, and trafficking; 2) reducing prolactin receptor (PRLR) levels in human T47D breast cancer cells augments GHR abundance and GH sensitivity; 3) novel, conformationally-sensitive anti-GHR ECD antibodies may be useful GH antagonists. We hypothesize: 1) JAK2 expression levels and PRLR expression levels strongly influence GH responsiveness; 2) GH-induced GHR conformational changes that underlie GH signaling are potential targets for therapeutic intervention. Our specific aims are: 1. Determine mechanisms by which JAK2 and PRLR regulate GHR processing, cel surface stability, and downregulation. We will study how GHR predimerization impacts JAK2's modulation of GHR trafficking and the role of GHR ICD tyrosine residues on GH-independent and GH-dependent GHR trafficking. Effects of PRLR expression on GHR availability, GHR-JAK2 association, and GH actions in breast cancer cells will be examined. 2. Determine in vivo efficacy of conformation-specific inhibitory anti-GHR ECD monoclonal antibodies. We will characterize inhibitory properties of two anti-GHR antibodies and Fab fragments in signaling studies, also assessing impact of PRLR expression. We will determine in vivo efficacy of these reagents to antagonize GH signaling and cancer explant growth. These studies probe important determinants of GH sensitivity. Completion will reveal mechanisms regulating cell surface GHR availability and fate and therapeutically relevant tools to modulate GH sensitivity. PUBLIC HEALTH RELEVANCE: Growth hormone is a key regulator of growth and metabolism and recent work suggests that antagonism of growth hormone action may be of therapeutic potential in certain cancers. These studies of the growth hormone receptor investigate the determinants of growth hormone sensitivity at the cellular level. The knowledge gained and the development of inhibitory anti-GH receptor monoclonal antibodies as potential therapeutics may have broad relevance in our understanding of normal physiology and in treatment of cancer.

描述（由申请人提供）：生长激素（GH）主要来源于垂体前叶，以内分泌方式调节脊椎动物的产后生长和代谢。最近的研究还表明自分泌衍生的 GH 和完整的 GH 轴在动物癌症的形成和行为中的作用。 GH 受体 (GHR) 是细胞表面糖蛋白细胞因子受体超家族成员，在其胞外结构域 (ECD) 中结合 GH，并通过其胞内结构域 (ICD) 与 JAK2 酪氨酸激酶的相互作用激活信号传导。我们最近对调节 GHR 可用性和激活机制的研究揭示了令人兴奋的见解，包括：1）JAK2 关联影响 GHR 表面呈现、稳定性和运输； 2) 降低人 T47D 乳腺癌细胞中催乳素受体 (PRLR) 水平可增加 GHR 丰度和 GH 敏感性； 3)新型的、构象敏感的抗GHR ECD抗体可能是有用的GH拮抗剂。我们假设：1）JAK2 表达水平和 PRLR 表达水平强烈影响 GH 反应性； 2) GH 诱导的 GHR 构象变化是 GH 信号传导的潜在目标。我们的具体目标是： 1. 确定 JAK2 和 PRLR 调节 GHR 加工、细胞表面稳定性和下调的机制。我们将研究 GHR 预二聚化如何影响 JAK2 对 GHR 运输的调节以及 GHR ICD 酪氨酸残基对 GH 独立和 GH 依赖性 GHR 运输的作用。将检查 PRLR 表达对乳腺癌细胞中 GHR 可用性、GHR-JAK2 关联和 GH 作用的影响。 2. 确定构象特异性抑制性抗 GHR ECD 单克隆抗体的体内功效。我们将在信号研究中表征两种抗 GHR 抗体和 Fab 片段的抑制特性，并评估 PRLR 表达的影响。我们将确定这些试剂拮抗 GH 信号传导和癌症外植体生长的体内功效。这些研究探讨了 GH 敏感性的重要决定因素。完成后将揭示调节细胞表面 GHR 可用性和命运的机制以及调节 GH 敏感性的治疗相关工具。 公共健康相关性：生长激素是生长和代谢的关键调节剂，最近的研究表明，生长激素作用的拮抗作用可能对某些癌症具有治疗潜力。这些生长激素受体的研究调查了细胞水平上生长激素敏感性的决定因素。所获得的知识以及抑制性抗 GH 受体单克隆抗体作为潜在疗法的开发可能与我们对正常生理学和癌症治疗的理解具有广泛的相关性。