College of Life Science and Bioengineering, Faculty of Environmental and Life Sciences, Beijing University of Technology, Beijing, 100124, China; State Key Laboratory of Proteomics, National Center for Protein Sciences (Beijing), Beijing Institute of Radiation Medicine, Beijing, 100850, China.
Institute of Health Service and Transfusion Medicine, Beijing, 100850, China.
Biochem Biophys Res Commun. 2023 Sep 3;671:229-235. doi: 10.1016/j.bbrc.2023.06.023. Epub 2023 Jun 7.
The process of erythroid differentiation is orchestrated at the molecular level by a complex network of transcription factors. Erythroid Krüppel-like factor (EKLF/KLF1) is a master erythroid gene regulator that directly regulates most aspects of terminal erythroid differentiation. However, the underlying regulatory mechanisms of EKLF protein stability are still largely unknown. In this study, we identified Vacuolar protein sorting 37 C (VPS37C), a core subunit of the Endosomal sorting complex required for transport-I (ESCRT-I) complex, as an essential regulator of EKLF stability. Our study showed that VPS37C interacts with EKLF and prevents K48-linked polyubiquitination of EKLF and proteasome-mediated EKLF degradation, thus enhancing EKLF protein stability and transcriptional activity. VPS37C overexpression in murine erythroleukemia (MEL) cells promotes hexamethylene bisacetamide (HMBA)-induced erythroid differentiation manifested by up-regulating erythroid-specific EKLF target genes and increasing benzidine-positive cells. In contrast, VPS37C knockdown inhibits HMBA-induced MEL cell erythroid differentiation. Particularly, the restoration of EKLF expression in VPS37C-knockdown MEL cells reverses erythroid-specific gene expression and hemoglobin production. Collectively, our study demonstrated VPS37C is a novel regulator of EKLF ubiquitination and degradation, which plays a positive role in erythroid differentiation of MEL cells by enhancing EKLF protein stability.
红细胞分化过程在分子水平上受到转录因子复杂网络的调控。红细胞 Krüppel 样因子 (EKLF/KLF1) 是一种主要的红细胞基因调控因子，直接调控红细胞终末分化的大多数方面。然而，EKLF 蛋白稳定性的潜在调节机制在很大程度上仍然未知。在这项研究中，我们鉴定出 Vacuolar protein sorting 37C (VPS37C)，一种内体分选复合物必需运输-I (ESCRT-I) 复合物的核心亚基，是 EKLF 稳定性的必需调节剂。我们的研究表明，VPS37C 与 EKLF 相互作用，防止 EKLF 的 K48 连接多泛素化和蛋白酶体介导的 EKLF 降解，从而增强 EKLF 蛋白稳定性和转录活性。在小鼠红白血病 (MEL) 细胞中过表达 VPS37C 可促进己二烯双乙酰胺 (HMBA) 诱导的红细胞分化，表现为上调红细胞特异性 EKLF 靶基因和增加联苯胺阳性细胞。相比之下，VPS37C 敲低抑制 HMBA 诱导的 MEL 细胞红细胞分化。特别是，在 VPS37C 敲低的 MEL 细胞中恢复 EKLF 表达可逆转红细胞特异性基因表达和血红蛋白产生。总之，我们的研究表明 VPS37C 是 EKLF 泛素化和降解的一种新型调节剂，通过增强 EKLF 蛋白稳定性，在 MEL 细胞的红细胞分化中发挥积极作用。
