Ubiquitin Ligase RBX2/SAG Regulates Mitochondrial Ubiquitination and Mitophagy.

IF 16.5 1区医学 Q1 CARDIAC & CARDIOVASCULAR SYSTEMS Circulation research Pub Date : 2024-07-19 Epub Date: 2024-06-14 DOI:10.1161/CIRCRESAHA.124.324285

Wenjuan Wang, Ermin Li, Jianqiu Zou, Chen Qu, Juan Ayala, Yuan Wen, Md Sadikul Islam, Neal L Weintraub, David J R Fulton, Qiangrong Liang, Jiliang Zhou, Jinbao Liu, Jie Li, Yi Sun, Huabo Su

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Abstract

Background: Clearance of damaged mitochondria via mitophagy is crucial for cellular homeostasis. Apart from Parkin, little is known about additional Ub (ubiquitin) ligases that mediate mitochondrial ubiquitination and turnover, particularly in highly metabolically active organs such as the heart.

Methods: In this study, we have combined in silico analysis and biochemical assay to identify CRL (cullin-RING ligase) 5 as a mitochondrial Ub ligase. We generated cardiomyocytes and mice lacking RBX2 (RING-box protein 2; also known as SAG [sensitive to apoptosis gene]), a catalytic subunit of CRL5, to understand the effects of RBX2 depletion on mitochondrial ubiquitination, mitophagy, and cardiac function. We also performed proteomics analysis and RNA-sequencing analysis to define the impact of loss of RBX2 on the proteome and transcriptome.

Results: RBX2 and CUL (cullin) 5, 2 core components of CRL5, localize to mitochondria. Depletion of RBX2 inhibited mitochondrial ubiquitination and turnover, impaired mitochondrial membrane potential and respiration, increased cardiomyocyte cell death, and has a global impact on the mitochondrial proteome. In vivo, deletion of the Rbx2 gene in adult mouse hearts suppressed mitophagic activity, provoked accumulation of damaged mitochondria in the myocardium, and disrupted myocardial metabolism, leading to the rapid development of dilated cardiomyopathy and heart failure. Similarly, ablation of RBX2 in the developing heart resulted in dilated cardiomyopathy and heart failure. The action of RBX2 in mitochondria is not dependent on Parkin, and Parkin gene deletion had no impact on the onset and progression of cardiomyopathy in RBX2-deficient hearts. Furthermore, RBX2 controls the stability of PINK1 (PTEN-induced kinase 1) in mitochondria.

Conclusions: These findings identify RBX2-CRL5 as a mitochondrial Ub ligase that regulates mitophagy and cardiac homeostasis in a Parkin-independent, PINK1-dependent manner.

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超泛素连接酶RBX2/SAG调控线粒体的超泛素化和丝裂。

背景：通过有丝分裂清除受损线粒体对细胞平衡至关重要。除了 Parkin 之外，人们对其他介导线粒体泛素化和周转的 Ub（泛素）连接酶知之甚少，尤其是在心脏等新陈代谢高度活跃的器官中：在这项研究中，我们结合了硅学分析和生化测定，确定 CRL（cullin-RING ligase）5 为线粒体泛素连接酶。我们生成了心肌细胞和缺乏 CRL5 催化亚基 RBX2（RING-box protein 2，又称 SAG [sensitive to apoptosis gene]）的小鼠，以了解 RBX2 缺失对线粒体泛素化、有丝分裂和心脏功能的影响。我们还进行了蛋白质组学分析和RNA测序分析，以确定RBX2缺失对蛋白质组和转录组的影响：结果：RBX2和CUL（cullin）5（CRL5的2个核心成分）定位于线粒体。缺失 RBX2 会抑制线粒体泛素化和周转，损害线粒体膜电位和呼吸，增加心肌细胞死亡，并对线粒体蛋白质组产生全面影响。在体内，成年小鼠心脏中 Rbx2 基因的缺失会抑制有丝分裂活性，导致受损线粒体在心肌中堆积，破坏心肌代谢，从而导致扩张型心肌病和心力衰竭的迅速发展。同样，在发育中的心脏中消融 RBX2 也会导致扩张型心肌病和心力衰竭。RBX2 在线粒体中的作用并不依赖于 Parkin，Parkin 基因的缺失对 RBX2 缺失型心脏心肌病的发生和发展没有影响。此外，RBX2 还能控制线粒体中 PINK1 的稳定性：这些研究结果发现，RBX2-CRL5是线粒体Ub连接酶，它以一种独立于Parkin、依赖于PINK1的方式调节有丝分裂和心脏稳态。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Circulation research 医学-外周血管病

CiteScore

29.60

自引率

2.00%

发文量

535

审稿时长

3-6 weeks

期刊介绍： Circulation Research is a peer-reviewed journal that serves as a forum for the highest quality research in basic cardiovascular biology. The journal publishes studies that utilize state-of-the-art approaches to investigate mechanisms of human disease, as well as translational and clinical research that provide fundamental insights into the basis of disease and the mechanism of therapies. Circulation Research has a broad audience that includes clinical and academic cardiologists, basic cardiovascular scientists, physiologists, cellular and molecular biologists, and cardiovascular pharmacologists. The journal aims to advance the understanding of cardiovascular biology and disease by disseminating cutting-edge research to these diverse communities. In terms of indexing, Circulation Research is included in several prominent scientific databases, including BIOSIS, CAB Abstracts, Chemical Abstracts, Current Contents, EMBASE, and MEDLINE. This ensures that the journal's articles are easily discoverable and accessible to researchers in the field. Overall, Circulation Research is a reputable publication that attracts high-quality research and provides a platform for the dissemination of important findings in basic cardiovascular biology and its translational and clinical applications.

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