Amino Acids

, 41:1185

Leucine nutrition in animals and humans: mTOR signaling and beyond

  • Fengna Li
  • Yulong Yin
  • Bie Tan
  • Xiangfeng Kong
  • Guoyao Wu
Review Article

Abstract

Macronutrients, such as protein or amino acid, not only supply calories but some components may also play as signaling molecules to affect feeding behavior, energy balance, and fuel efficiency. Leucine, a branched-chain amino acid is a good example. After structural roles are satisfied, the ability of leucine to function as signal and oxidative substrate is based on a sufficient intracellular concentration. Therefore, leucine level must be sufficiently high to play the signaling and metabolic roles. Leucine is not only a substrate for protein synthesis of skeletal muscle, but also plays more roles beyond that. Leucine activates signaling factor of mammalian target of rapamycin (mTOR) to promote protein synthesis in skeletal muscle and in adipose tissue. It is also a major regulator of the mTOR sensitive response of food intake to high protein diet. Meanwhile, leucine regulates blood glucose level by promoting gluconeogenesis and aids in the retention of lean mass in a hypocaloric state. It is beneficial to animal nutrition and clinical application and extrapolation to humans.

Keywords

Leucine nutrition mTOR signaling 

Abbreviations

AA

Amino acid

AgRP

Agouti-related protein

AMPK

AMP-activated protein kinase

BCAA

Branched-chain amino acid

BCATm

Mitochondrial branched-chain aminotransferase

BW

Body weight

4E-BP1

Eukaryotic initiation factor 4E binding protein 1

mTOR

Mammalian target of rapamycin

mTORC1

mTOR complex 1

NPY

Neuropeptide Y

PI3K

Phosphatidylinositol 3-kinase

S6K1

Ribosomal protein S6 kinase 1

UCP3

Uncoupling protein 3

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Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Fengna Li
    • 1
  • Yulong Yin
    • 1
  • Bie Tan
    • 1
  • Xiangfeng Kong
    • 1
  • Guoyao Wu
    • 2
  1. 1.Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical AgricultureChinese Academy of SciencesHunanChina
  2. 2.Department of Animal ScienceTexas A&M UniversityCollege StationUSA

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