Lysine, as the first limiting amino acid in dairy cows, has been shown to play an important role in milk synthesis and cell proliferation. However, the underlying mechanism remains unclear. In this study, we isolated bovine primary mammary epithelial cells (BMECs) and studied the mechanism in which lysine promotes cell proliferation and β-casein synthesis through overexpression and knockdown of CDK1 and supplements BCH, U0126, and rapamycin in BMECs. Results show that 0.7 mM lysine can significantly promote cell proliferation and the synthesis of β-casein in BMECs. In addition, lysine activates the ERK signaling pathway to promote the expression of CDK1. Further studies have shown that CDK1 can promote cell proliferation and the synthesis of β-casein through the mTOR signaling pathway in BMECs. Lastly, lysine can promote cell proliferation and the synthesis of β-casein through SLC6A14 in BMECs. The above results indicate that lysine promotes cell proliferation and the synthesis of β-casein through the SLC6A14-ERK-CDK1-mTOR signaling pathway in BMECs.

赖氨酸作为奶牛体内的第一限制性氨基酸，已被证明在乳汁合成和细胞增殖中起重要作用。然而，潜在的机制仍不清楚。在这项研究中，我们分离了牛原代乳腺上皮细胞 (BMEC)，并研究了赖氨酸通过过表达和敲低 BMEC 中的 CDK1 和补充剂 BCH、U0126 和雷帕霉素促进细胞增殖和 β-酪蛋白合成的机制。结果表明，0.7 mM赖氨酸可显着促进BMECs细胞增殖和β-酪蛋白的合成。此外，赖氨酸激活ERK信号通路促进CDK1的表达。进一步的研究表明，CDK1可以通过BMECs中的mTOR信号通路促进细胞增殖和β-酪蛋白的合成。最后，赖氨酸可通过BMECs中的SLC6A14促进细胞增殖和β-酪蛋白的合成。以上结果表明赖氨酸通过SLC6A14-ERK-CDK1-mTOR信号通路促进BMECs细胞增殖和β-酪蛋白的合成。