Regulation of milk synthesis in the bovine mammary gland. The role of MRCKα in prolactin- and Amino acid-evoked lactogenesis

Samenvatting

Understanding the regulation of milk synthesis by nutrients is important for optimizing the formulation of dairy cow diets, improving the efficiency of feed and N utilization, increasing milk protein production, and reducing N emission and environmental pollution. The thesis investigated 1) interaction between dietary lysine to methionine ratio and glucose concentration, and their potential regulation mechanism of milk protein synthesis, and 2) the role of MRCKα (an important kinase in signaling pathways) in amino acid- and prolactin-stimulated milk synthesis, and 3) mechanisms of MRCKα in regulating milk protein synthesis, in particular the physical interaction between MRCKα and 14-3-3γ, and their binding role in milk protein synthesis. MRCKα was shown to be a novel regulator of milk synthesis and cell proliferation in bovine mammary epithelial cells. An integrated network of signaling pathways was proposed, which regulates milk synthesis in bovine mammary epithelial cells under stimulation by amino acids, prolactin or glucose.