Department of Biology, Croucher Institute for Environmental Sciences, Hong Kong Baptist University, Hong Kong SAR, China.
Department of Biology, Croucher Institute for Environmental Sciences, Hong Kong Baptist University, Hong Kong SAR, China
Life Sci Alliance. 2022 Jul 7;5(11). doi: 10.26508/lsa.202201497. Print 2022 Nov.
Stanniocalcin-1 (STC1) is a hypocalcemic hormone originally identified in bony fishes. The mammalian homolog is found to be involved in inflammation and carcinogenesis, among other physiological functions. In this study, we used the TriCEPS-based ligand-receptor methodology to identify the putative binding proteins of human STC1 (hSTC1) in the human leukemia monocytic cell line, ThP-1. LC-MS/MS analysis of peptides from shortlisted hSTC1-binding proteins detected 32 peptides that belong to IGF2/MPRI. Surface plasmon resonance assay demonstrated that hSTC1 binds to immobilized IGF2R/MPRI with high affinity (10-20 nM) and capacity (Rmax 70-100%). The receptor binding data are comparable with those of (CREG) cellular repressor of E1A-stimulated gene a known ligand of IGF2R/MPRI, with Rmax of 75-80% and affinity values of 1-2 nM. The surface plasmon resonance competitive assays showed CREG competed with hSTC1 in binding to IGF2R/MPRI. The biological effects of hSTC1 on ThP-1 cells were demonstrated via IGF2R/MPRI to significantly reduce secreted levels of IL-1β. This is the first study to reveal the high-affinity binding of hSTC1 to the membrane receptor IGF2R/MPRI.
斯钙素-1（STC1）是一种最初在硬骨鱼中发现的降血钙激素。哺乳动物同源物被发现参与炎症和致癌作用，以及其他生理功能。在这项研究中，我们使用基于 TriCEPS 的配体-受体方法，在人白血病单核细胞系 ThP-1 中鉴定人 STC1（hSTC1）的假定结合蛋白。从入选的 hSTC1 结合蛋白的肽的 LC-MS/MS 分析检测到 32 个肽，属于 IGF2/MPRI。表面等离子体共振分析表明，hSTC1 以高亲和力（10-20 nM）和容量（Rmax 70-100%）与固定化 IGF2R/MPRI 结合。受体结合数据与已知 IGF2R/MPRI 配体（CREG）细胞 E1A 刺激基因的细胞抑制剂的受体结合数据相当，Rmax 为 75-80%，亲和力值为 1-2 nM。表面等离子体共振竞争分析表明，CREG 与 hSTC1 竞争结合 IGF2R/MPRI。hSTC1 对 ThP-1 细胞的生物学效应通过 IGF2R/MPRI 显著降低了 IL-1β 的分泌水平。这是首次揭示 hSTC1 与膜受体 IGF2R/MPRI 具有高亲和力结合的研究。
