应激颗粒的动态平衡由 TRIM21 介导的 G3BP1 泛素化和自噬依赖性应激颗粒消除来调节。
Stress granule homeostasis is modulated by TRIM21-mediated ubiquitination of G3BP1 and autophagy-dependent elimination of stress granules.
机构信息
School of Life Science and Technology, ShanghaiTech University, Shanghai, China.
CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China.
出版信息
Autophagy. 2023 Jul;19(7):1934-1951. doi: 10.1080/15548627.2022.2164427. Epub 2023 Jan 24.
Eukaryotic stress granules (SGs) are highly dynamic assemblies of untranslated mRNAs and proteins that form through liquid-liquid phase separation (LLPS) under cellular stress. SG formation and elimination process is a conserved cellular strategy to promote cell survival, although the precise regulation of this process is poorly understood. Here, we screened six E3 ubiquitin ligases present in SGs and identified TRIM21 (tripartite motif containing 21) as a central regulator of SG homeostasis that is highly enriched in SGs of cells under arsenite-induced oxidative stress. Knockdown of promotes SG formation whereas overexpression of inhibits the formation of physiological and pathological SGs associated with neurodegenerative diseases. TRIM21 catalyzes K63-linked ubiquitination of the SG core protein, G3BP1 (G3BP stress granule assembly factor 1), and G3BP1 ubiquitination can effectively inhibit LLPS, . Recent reports suggested the involvement of macroautophagy/autophagy, as a stress response pathway, in the regulation of SG homeostasis. We systematically investigated well-defined autophagy receptors and identified SQSTM1/p62 (sequestosome 1) and CALCOCO2/NDP52 (calcium binding and coiled-coil domain 2) as the primary receptors that directly interact with G3BP1 during arsenite-induced stress. Endogenous SQSTM1 and CALCOCO2 localize to the periphery of SGs under oxidative stress and mediate SG elimination, as single knockout of each receptor causes accumulation of physiological and pathological SGs. Collectively, our study broadens the understanding in the regulation of SG homeostasis by showing that TRIM21 and autophagy receptors modulate SG formation and elimination respectively, suggesting the possibility of clinical targeting of these molecules in therapeutic strategies for neurodegenerative diseases. ACTB: actin beta; ALS: amyotrophic lateral sclerosis; BafA1: bafilomycin A; BECN1: beclin 1; C9orf72: C9orf72-SMCR8 complex subunit; CALCOCO2/NDP52: calcium binding and coiled-coil domain 2; Co-IP: co-immunoprecipitation; DAPI: 4',6-diamidino-2-phenylindole; FTD: frontotemporal dementia; FUS: FUS RNA binding protein; G3BP1: G3BP stress granule assembly factor 1; GFP: green fluorescent protein; LLPS: liquid-liquid phase separation; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; NBR1: NBR1 autophagy cargo receptor; NES: nuclear export signal; OPTN: optineurin; RFP: red fluorescent protein; SQSTM1/p62: sequestosome 1; SG: stress granule; TAX1BP1: Tax1 binding protein 1; TOLLIP: toll interacting protein; TRIM21: tripartite motif containing 21; TRIM56: tripartite motif containing 56; UB: ubiquitin; ULK1: unc-51 like autophagy activating kinase 1; WT: wild-type.
真核细胞应激颗粒(SGs)是一种高度动态的未翻译 mRNA 和蛋白质的集合体,在细胞应激下通过液-液相分离(LLPS)形成。SG 的形成和消除过程是一种保守的细胞存活策略,尽管其确切的调控机制还不清楚。在这里,我们筛选了六种存在于 SG 中的 E3 泛素连接酶,鉴定出 TRIM21(包含三个结构域的 21 号蛋白)是 SG 动态平衡的核心调节因子,在亚砷酸盐诱导的氧化应激下,TRIM21 在 SG 中高度富集。敲低 会促进 SG 的形成,而过表达 则会抑制与神经退行性疾病相关的生理和病理 SG 的形成。TRIM21 催化 SG 核心蛋白 G3BP1(G3BP 应激颗粒组装因子 1)的 K63 连接泛素化,G3BP1 泛素化可以有效地抑制 LLPS。最近的报道表明,巨自噬/自噬作为一种应激反应途径,参与了 SG 动态平衡的调控。我们系统地研究了明确的自噬受体,并鉴定出 SQSTM1/p62(自噬相关蛋白 1)和 CALCOCO2/NDP52(钙结合和卷曲螺旋结构域 2)是在亚砷酸盐诱导应激下与 G3BP1 直接相互作用的主要受体。内源性 SQSTM1 和 CALCOCO2 在氧化应激下定位于 SG 的外周,并介导 SG 的消除,因为每个受体的单一敲除都会导致生理和病理 SG 的积累。总的来说,我们的研究拓宽了对 SG 动态平衡调控的理解,表明 TRIM21 和自噬受体分别调节 SG 的形成和消除,这表明在神经退行性疾病的治疗策略中靶向这些分子的可能性。ACTB:肌动蛋白β;ALS:肌萎缩侧索硬化症;BafA1:巴佛洛霉素 A;BECN1:自噬相关蛋白 1;C9orf72:C9orf72-SMCR8 复合物亚基;CALCOCO2/NDP52:钙结合和卷曲螺旋结构域 2;Co-IP:免疫共沉淀;DAPI:4',6-二脒基-2-苯基吲哚;FTD:额颞叶痴呆;FUS:FUS RNA 结合蛋白;G3BP1:G3BP 应激颗粒组装因子 1;GFP:绿色荧光蛋白;LLPS:液-液相分离;MAP1LC3/LC3:微管相关蛋白 1 轻链 3;NBR1:NBR1 自噬 cargo 受体;NES:核输出信号;OPTN:optineurin;RFP:红色荧光蛋白;SQSTM1/p62:自噬相关蛋白 1;SG:应激颗粒;TAX1BP1:Tax1 结合蛋白 1;TOLLIP:Toll 相互作用蛋白;TRIM21:包含三个结构域的 21 号蛋白;TRIM56:包含三个结构域的 56 号蛋白;UB:泛素;ULK1:unc-51 样自噬激活激酶 1;WT:野生型。
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