Research Progress on Interaction between Activating Transcription Factor 4 and Mammalian Target of Rapamycin Complex 1 in Regulating Milk Protein Synthesis of Lactating Cows

College of Animal Science and Technology,Qingdao Agricultural University,Qingdao 266109,China;State Key Laboratory of Animal Nutrition,Institute of Animal Sciences,Chinese Academy of Agricultural Sciences,Beijing 100193,China

amino acid supply%ATF4%mTORC1%interaction%low-protein diet%milk protein synthesis%dairy cows

With the implementation of the national"double-carbon"strategy,the low efficiency of dietary nitrogen conversion efficiency in lactating cows as well as the concomitant waste of feed resources and increased nitrogen emissions have increasingly restricted the development of dairy industry.Supplementation of specific amino acid(AA)in low-protein diet is an important measure to improve the dietary nitrogen conversion efficiency of dairy cows in practice,but the theoretical basis underlying its application is remain unclear.Previous studies showed that AA supplementation promoted protein synthesis through mechanistic target of rapamycin complex 1(mTORC1)pathway,while AA deficiency inhibited mTORC1 activity through activating transcription factor 4(ATF4),and mTORC1 mediated ATF4 to regulate AA transport,metabolism and milk protein synthesis.Therefore,the interaction between ATF4 and mTORC1 provides a key insight to study the mechanisms underlying the regulating effects of limiting AA on milk protein synthesis in dairy cows fed low-protein diet.This paper reviewed the research progress on the interaction between ATF4 and mTORC1 in balancing AA supply and milk protein output,which might give a reference for investigating the pathways of limiting AA mediating protein synthesis and the formulation of low-protein diet in dairy cows.