Department of Pathology, The First People's Hospital of Shizuishan, Affiliated to Ningxia Medical University, Shizuishan, China.
School of Clinical Medicine, Ningxia Medical University, Yinchuan, China.
Sci Rep. 2023 Feb 3;13(1):1999. doi: 10.1038/s41598-023-28905-5.
Peroxisome proliferator-activated receptor gamma (PPAR γ) plays key roles in the development, physiology, reproduction, and homeostasis of organisms. Its expression and activity are regulated by various posttranslational modifications. We previously reported that E3 ubiquitin ligase muscle ring finger protein 2 (MuRF2) inhibits cardiac PPAR γ1 protein level and activity, eventually protects heart from diabetic cardiomyopathy; furthermore, by GST-pulldown assay, we found that MuRF2 modifies PPAR γ1 via poly-ubiquitination and accelerates PPAR γ1 proteasomal degradation. However, the key ubiquitination site on PPAR γ that MuRF2 targets for remains unclear. In the present study, we demonstrate that lysine site 222 is the receptor of MuRF2-mediated PPAR γ1 ubiquitination modification, using prediction of computational models, immunoprecipitation, ubiquitination assays, cycloheximide chasing assay and RT-qPCR. Our findings elucidated the underlying details of MuRF2 prevents heart from diabetic cardiomyopathy through the PPAR γ1 regulatory pathway.
过氧化物酶体增殖物激活受体 γ（PPAR γ）在生物的发育、生理、生殖和内稳态中发挥关键作用。其表达和活性受到多种翻译后修饰的调节。我们之前的研究表明，E3 泛素连接酶肌肉环指蛋白 2（MuRF2）抑制心脏 PPAR γ1 蛋白水平和活性，最终保护心脏免受糖尿病心肌病的影响；此外，通过 GST 下拉测定，我们发现 MuRF2 通过多泛素化修饰 PPAR γ1，并加速 PPAR γ1 的蛋白酶体降解。然而，MuRF2 针对的 PPAR γ 的关键泛素化位点仍不清楚。在本研究中，我们使用计算模型的预测、免疫沉淀、泛素化测定、环己酰亚胺追踪测定和 RT-qPCR，证明了赖氨酸 222 是 MuRF2 介导的 PPAR γ1 泛素化修饰的受体。我们的研究结果阐明了 MuRF2 通过 PPAR γ1 调节途径防止心脏发生糖尿病心肌病的潜在机制。
