UFL1 is an ufmylation (a novel post-translational modification) E3 ligase, mainly located in the endoplasmic reticulum (ER), that has emerged as a significant regulator of several physiological and pathological processes. Yet its physiological function in milk synthesis in bovine mammary epithelial cells (BMECs) remains unknown. In this study, we investigated the effects of UFL1 in milk protein and fat synthesis–related gene expression, with a particular emphasis on the role of UFL1 in LPS-treated BMECs. Results showed that UFL1 depletion significantly reduced the expression of milk protein and fat synthesis–related gene and mTOR phosphorylation in both normal and LPS-treated BMECs. Overexpression of UFL1 enhanced the activation of the mTOR and milk protein and fat synthesis–related gene expression. Collectively, these above results strongly demonstrate that UFL1 could regulate milk protein and fat synthesis–related gene expression of BMECs probably via the mTOR signaling pathway.

UFL1 是一种 ufmylation（一种新型翻译后修饰）E3 连接酶，主要位于内质网 (ER) 中，已成为几种生理和病理过程的重要调节剂。然而，其在牛乳腺上皮细胞 (BMECs) 的牛奶合成中的生理功能仍然未知。在这项研究中，我们研究了 UFL1 对牛奶蛋白和脂肪合成相关基因表达的影响，特别强调了 UFL1 在 LPS 处理的 BMEC 中的作用。结果表明，在正常和 LPS 处理的 BMEC 中，UFL1 消耗显着降低了牛奶蛋白和脂肪合成相关基因的表达以及 mTOR 磷酸化。UFL1 的过表达增强了 mTOR 的激活以及乳蛋白和脂肪合成相关基因的表达。总的来说，