scholarly journals Leucyl-tRNA Synthetase Regulates Lactation and Cell Proliferation via mTOR Signaling in Dairy Cow Mammary Epithelial Cells

2014 ◽  
Vol 15 (4) ◽  
pp. 5952-5969 ◽  
Author(s):  
Lina Wang ◽  
Ye Lin ◽  
Yanjie Bian ◽  
Lili Liu ◽  
Li Shao ◽  
...  
2012 ◽  
Vol 92 (4) ◽  
pp. 433-442 ◽  
Author(s):  
Limin Lu ◽  
Xuejun Gao ◽  
Qingzhang Li ◽  
Jianguo Huang ◽  
Rong Liu ◽  
...  

Lu, L., Gao, X., Li, Q., Huang, J., Liu, R. and Li, H. 2012. Comparative phosphoproteomics analysis of the effects of L-methionine on dairy cow mammary epithelial cells. Can. J. Anim. Sci. 92: 433–442. L-methionine is an essential amino acid that plays fundamental roles in protein synthesis. Many nuclear phosphorylated proteins such as Stat5 (signal transducer and activator of transcription 5) and mTOR (mammalian target of rapamycin) regulate milk protein synthesis. But a comprehensive understanding of transcriptional and posttranscriptional regulation of milk protein synthesis is lacking. In the current study, two-dimensional gel electrophoresis (2-DE)/MS-based proteomics analysis was used to identify phosphoproteins responsible for milk protein synthesis in dairy cow mammary epithelial cells (DCMECs). The effects of L-methionine on DCMECs were analyzed by CASY (Counter Analyser System) technique, reversed phase high performance liquid chromatography. The results showed that rate of cell proliferation and expression of β-casein were increased in DCMECs treated with 0.6 mM L-methionine for 24 h. Five proteins for which expression was significantly increased in DCMECs were selected, and their expression changes were verified by quantitative real-time PCR and Western blot analysis. The five up-regulated expressed phosphoproteins included Staphylococcal nuclease domain-containing protein 1(SND1), Septin-6, Glycyl-tRNA synthetase (GARS), Twinfilin-1 and eukaryotic elongation factor1-beta (eEF1B). This study revealed that availability of L-methionine influences the levels of nuclear phosphorylated proteins of DCMECs which opens a new avenue for the study of the molecular mechanism linking to milk protein synthesis.


2015 ◽  
Vol 34 (8) ◽  
pp. 524-533 ◽  
Author(s):  
Nan Jiang ◽  
Yu Wang ◽  
Zhiqiang Yu ◽  
Lijun Hu ◽  
Chaonan Liu ◽  
...  

2020 ◽  
pp. 1-7
Author(s):  
Jianfa Wang ◽  
Shuai Lian ◽  
Jun Song ◽  
Hai Wang ◽  
Xu Zhang ◽  
...  

Abstract Lipopolysaccharides (LPS) could induce milk fat depression via regulating the body and blood fat metabolism. However, it is not completely clear how LPS might regulate triglyceride synthesis in dairy cow mammary epithelial cells (DCMECs). DCMECs were isolated and purified from dairy cow mammary tissue and treated with LPS. The level of triglyceride synthesis, the expression and activity of the liver X receptor α (LXRα), enzymes related to de novo fatty acid synthesis, and the expression of the fatty acid transporters were investigated. We found that LPS decreased the level of triglyceride synthesis via a down-regulation of the transcription, translation, and nuclear translocation level of the LXRα. The results also indicated that the transcription level of the LXRα target genes, sterol regulatory element binding protein 1 (SREBP1), fatty acid synthetase (FAS), acetyl-CoA carboxylase-1 (ACC1), were significantly down-regulated in DCMECs after LPS treatment. Our data may provide new insight into the mechanisms of milk fat depression caused by LPS.


2004 ◽  
Vol 15 (5) ◽  
pp. 2302-2311 ◽  
Author(s):  
Yijun Yi ◽  
Anne Shepard ◽  
Frances Kittrell ◽  
Biserka Mulac-Jericevic ◽  
Daniel Medina ◽  
...  

This study demonstrated, for the first time, the following events related to p19ARFinvolvement in mammary gland development: 1) Progesterone appears to regulate p19ARFin normal mammary gland during pregnancy. 2) p19ARFexpression levels increased sixfold during pregnancy, and the protein level plateaus during lactation. 3) During involution, p19ARFprotein level remained at high levels at 2 and 8 days of involution and then, declined sharply at day 15. Absence of p19ARFin mammary epithelial cells leads to two major changes, 1) a delay in the early phase of involution concomitant with downregulation of p21Cip1and decrease in apoptosis, and 2) p19ARFnull cells are immortal in vivo measured by serial transplantion, which is partly attributed to complete absence of p21Cip1compared with WT cells. Although, p19ARFis dispensable in mammary alveologenesis, as evidenced by normal differentiation in the mammary gland of pregnant p19ARFnull mice, the upregulation of p19ARFby progesterone in the WT cells and the weakness of p21Cip1in mammary epithelial cells lacking p19ARFstrongly suggest that the functional role(s) of p19ARFin mammary gland development is critical to sustain normal cell proliferation rate during pregnancy and normal apoptosis in involution possibly through the p53-dependent pathway.


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