Stub1 维持胚胎干细胞中主要转录因子的蛋白质平衡。
Stub1 maintains proteostasis of master transcription factors in embryonic stem cells.
机构信息
Translational Research Institute, Henan Provincial People's Hospital, Henan Key Laboratory of Stem Cell Differentiation and Modification, School of Clinical Medicine, Henan University, Zhengzhou 450003, China; Zhengzhou City Key Laboratory of Long Non-coding RNA and Cancer Metabolism, Henan Provincial Key Laboratory of Long Non-coding RNA and Cancer Metabolism, Henan International Joint Laboratory of Non-coding RNA and Metabolism in Cancer, Zhengzhou 450003, China.
Translational Research Institute, Henan Provincial People's Hospital, Henan Key Laboratory of Stem Cell Differentiation and Modification, School of Clinical Medicine, Henan University, Zhengzhou 450003, China; Zhengzhou City Key Laboratory of Long Non-coding RNA and Cancer Metabolism, Henan Provincial Key Laboratory of Long Non-coding RNA and Cancer Metabolism, Henan International Joint Laboratory of Non-coding RNA and Metabolism in Cancer, Zhengzhou 450003, China; Research Center on Aging, Centre Intégré Universitaire de Santé et Services Sociaux de l'Estrie-Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, QC, Canada; Department of Biochemistry and Functional Genomics, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC J1E 4K8 Canada.
出版信息
Cell Rep. 2022 Jun 7;39(10):110919. doi: 10.1016/j.celrep.2022.110919.
The pluripotency and differentiation states of embryonic stem cells (ESCs) are regulated by a set of core transcription factors, primarily Sox2, Oct4, and Nanog. Although their transcriptional regulation has been studied extensively, the contribution of posttranslational modifications in Sox2, Oct4, and Nanog are poorly understood. Here, using a CRISPR-Cas9 knockout library screen in murine ESCs, we identify the E3 ubiquitin ligase Stub1 as a negative regulator of pluripotency. Manipulation of Stub1 expression in murine ESCs shows that ectopic Stub1 expression significantly reduces the protein half-life of Sox2, Oct4, and Nanog. Mechanistic investigations reveal Stub1 catalyzes the polyubiquitination and 26S proteasomal degradation of Sox2 and Nanog through K48-linked ubiquitin chains and Oct4 via K63 linkage. Stub1 deficiency positively enhances somatic cell reprogramming and delays differentiation, whereas its enforced expression triggers ESC differentiation. The discovery of Stub1 as an integral pluripotency regulator strengthens our understanding of ESC regulation beyond conventional transcriptional control mechanisms.
胚胎干细胞（ESCs）的多能性和分化状态由一组核心转录因子调控，主要是 Sox2、Oct4 和 Nanog。尽管它们的转录调控已经得到了广泛的研究，但 Sox2、Oct4 和 Nanog 的翻译后修饰的贡献还知之甚少。在这里，我们使用 CRISPR-Cas9 敲除文库筛选在小鼠 ESCs 中，确定 E3 泛素连接酶 Stub1 是多能性的负调控因子。在小鼠 ESCs 中操纵 Stub1 的表达表明，异位 Stub1 表达显著降低了 Sox2、Oct4 和 Nanog 的蛋白半衰期。机制研究表明 Stub1 通过 K48 连接的泛素链催化 Sox2 和 Nanog 的多泛素化和 26S 蛋白酶体降解，通过 K63 连接催化 Oct4 的多泛素化。Stub1 缺乏可显著增强体细胞核重编程并延迟分化，而其过表达则会触发 ESC 分化。Stub1 作为一个完整的多能性调节因子的发现，增强了我们对 ESC 调控的理解，超越了传统的转录调控机制。
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