DIRECT CALPAIN-PTH1R BINDING AFFECTS ACTIONS OF PTH/PTHrP

描述(申请人提供)：PTH1R与支架蛋白的结合是甲状旁腺激素(PTH)和甲状旁腺激素相关肽(PTHrP)以细胞和膜特异性方式发挥作用的关键。甲状旁腺素和甲状旁腺素受体(PTH1R)属于G蛋白偶联受体。甲状旁腺素的作用主要是通过直接作用于骨骼和肾脏来维持钙稳态。PTHrP是一种细胞生长和分化的旁分泌调节因子，其在肿瘤细胞中的异位表达与恶性肿瘤的骨转移和高钙血症有关。因此，研究PTH1R通过甲状旁腺激素和甲状旁腺素受体的信号转导和生理功能，对于了解疾病的发病机制和开发新的治疗方法具有重要意义。本研究的主要目的是研究与甲状旁腺激素1受体(PTH1R)结合的钙蛋白小亚基(28 kDa亚基)在甲状旁腺激素(PTH)和/或甲状旁腺素受体(PTHrP)介导的信号和作用中的作用。特定目的1定义了Calain介导的PTH1R的切割及其在PTH介导的细胞内事件中的作用。特定目的2研究了Calain作为甲状旁腺素诱导的下游过程的调节器的作用。特异性目的3表征体内成骨细胞特异性缺失Capn4的小鼠以及从这些小鼠分离的Capn4缺失的成骨细胞的表型。

DESCRIPTION (provided by applicant): The PTH1R binding to scaffolding proteins is key to the actions of parathyroid hormone (PTH) and PTH-related peptide (PTHrP) in a cell- and membrane-specific manner. A receptor for PTH and PTHrP (PTH1R) belongs to G-protein coupling receptors (GPCR). PTH functions primarily to maintain calcium homeostasis through direct action on bone and kidney. PTHrP is a paracrine regulator of cellular growth and differentiation, and its ectopic expression in tumor cells is associated with bone metastasis and hypercalcemia in malignancy. Thus, to study signaling and physiological function of PTH1R via PTH and PTHrP is essential for understanding of mechanisms of diseases and developing novel therapy. The primary research goal is to investigate the role of calpain small subunits (the 28-kDa subunit), a novel interactor, binding to the parathyroid hormone 1 receptor (PTH1R) on PTH and/or PTHrP-mediated signaling and actions. Specific Aim 1 defines calpain-mediated cleavage of the PTH1R and its role on PTH-mediated intracellular events. Specific Aim 2 examines the role of calpain as a modulator of PTH-elicited downstream processes. Specific Aim 3 characterizes the phenotype of mice with osteoblast-specific deletion of Capn4 in vivo and of Capn4-null osteoblsts isolated from these mice.