Saltar al contenido
Merck

Seryl-tRNA synthetase is involved in methionine stimulation of β-casein synthesis in bovine mammary epithelial cells.

The British journal of nutrition (2019-11-13)
Wenting Dai, Fengqi Zhao, Jianxin Liu, Hongyun Liu
RESUMEN

Despite the well-characterised mechanisms of amino acids (AA) regulation of milk protein synthesis in mammary glands (MG), the underlying specific AA regulatory machinery in bovine MG remains further elucidated. As methionine (Met) is one of the most important essential and limiting AA for dairy cows, it is crucial to expand how Met exerts its regulatory effects on dairy milk protein synthesis. Our previous work detected the potential regulatory role of seryl-tRNA synthetase (SARS) in essential AA (EAA)-stimulated bovine casein synthesis. Here, we investigated whether and how SARS participates in Met stimulation of casein production in bovine mammary epithelial cells (BMEC). With or without RNA interference against SARS, BMEC were treated with the medium in the absence (containing all other EAA and devoid of Met alone)/presence (containing 0·6 mm of Met in the medium devoid of Met alone) of Met. The protein abundance of β-casein and members of the mammalian target of rapamycin (mTOR) and general control nonderepressible 2 (GCN2) pathways was determined by immunoblot assay after 6 h treatment, the cell viability and cell cycle progression were determined by cell counting and propidium iodide-staining assay after 24 h treatment, and protein turnover was determined by l-[ring-3H5]phenylalanine isotope tracing assay after 48 h treatment. In the absence of Met, there was a general reduction in cell viability, total protein synthesis and β-casein production; in contrast, total protein degradation was enhanced. SARS knockdown strengthened these changes. Finally, SARS may work to promote Met-stimulated β-casein synthesis via affecting mTOR and GCN2 routes in BMEC.

MATERIALES
Referencia del producto
Marca
Descripción del producto

Sigma-Aldrich
L-Glutamina, meets USP testing specifications, suitable for cell culture, 99.0-101.0%, from non-animal source
Sigma-Aldrich
Hydrocortisone, BioReagent, suitable for cell culture
Sigma-Aldrich
Epidermal Growth Factor from murine submaxillary gland, EGF, suitable for cell culture
Sigma-Aldrich
L-Metionina, reagent grade, ≥98% (HPLC)
Sigma-Aldrich
Insulina from bovine pancreas, ≥25 USP units/mg (HPLC), powder
Sigma-Aldrich
holo-Transferrin bovine, Iron-saturated, BioReagent, suitable for cell culture