Institute of Pharmacology and Toxicology, University of Würzburg, Würzburg, Germany.
Interdisciplinary Center for Clinical Research, University Hospital of Würzburg, Würzburg, Germany.
Front Endocrinol (Lausanne). 2022 Feb 22;13:839351. doi: 10.3389/fendo.2022.839351. eCollection 2022.
Parathyroid hormone 1 receptor (PTH1R) is a member of the class B family of G protein-coupled receptors, which are characterized by a large extracellular domain required for ligand binding. We have previously shown that the extracellular domain of PTH1R is subject to metalloproteinase cleavage that is regulated by ligand-induced receptor trafficking and leads to impaired stability of PTH1R. In this work, we localize the cleavage site in the first loop of the extracellular domain using amino-terminal protein sequencing of purified receptor and by mutagenesis studies. We further show, that a receptor mutant not susceptible to proteolytic cleavage exhibits reduced signaling to G and increased activation of G compared to wild-type PTH1R. These findings indicate that the extracellular domain modulates PTH1R signaling specificity, and that its cleavage affects receptor signaling.
甲状旁腺激素 1 受体 (PTH1R) 是 G 蛋白偶联受体家族 B 类的成员，其特征是具有一个大的细胞外结构域，该结构域对于配体结合是必需的。我们之前已经表明，PTH1R 的细胞外结构域受到金属蛋白酶切割的调节，这种切割受配体诱导的受体运输调节，并导致 PTH1R 的稳定性受损。在这项工作中，我们使用纯化受体的氨基末端蛋白测序和突变研究来定位细胞外结构域第一环中的切割位点。我们进一步表明，与野生型 PTH1R 相比，不易受蛋白水解切割的受体突变体表现出降低的 G 信号转导和增加的 G 激活。这些发现表明细胞外结构域调节 PTH1R 信号转导特异性，并且其切割影响受体信号转导。
