Role of Ran GTPase in regulating milk protein synthesis signaling pathways in bovine mammary epithelial cells

RAN, A member of the small GTPase superfamily, is involved in various cellular signaling pathways. That regulates cell cycle progression and protein synthesis. This study aimed to investigate how Ran influences key signaling pathways associated with cell survival, proliferation, and milk protein synthesis (mTOR and Jak2/Stat5). Tissue samples were obtained from six mid-lactation Holstein dairy cows with high genetic merit. Western blot analysis was performed to determine the expression levels of mTOR, phosphorylated mTOR (p-mTOR) , Stat5 and phosphorylated Stat5 (p-Stat5) after Ran overexpression after Ran timely and stable transfection, the β-casein secreted by bovine mammary epithelial cells (BMECs) was quantified using HPLC and Cell viability was assessed with CASY cell counter. The results showed that after Ran Overexpression significantly enhanced cell viability and increased the expression of mTOR , p-mTOR , Stat5 and p-Stat5. The cell viability was significantly increased, furthermore the expression of mTOR, p-mTOR, Stat5, and p-Stat5 were also significantly increased. Thus, these findings suggest that Ran positively regulates the Jak2/Stat5 pathway and mTOR Signaling pathways, thereby promoting milk protein synthesis in BMECs.