British Journal of Nutrition

Full Papers

Section Two: Specific metabolic roles of amino acids, and the paradigm of optimal, as opposed to minimal dietary protein and amino acid requirements for performance, long-term health and optimal organ function

New perspectives in the control of body protein metabolism

Margaret A. McNurlan 

Department of Surgery, Stony Brook University Medical Center, Stony Brook, New York 11794-8191, USA

Abstract

Recent advances in elucidating the mechanisms that control body protein synthesis and degradation both expand and complicate our understanding of how these processes are regulated. This review presents an introduction to the multiple regulatory systems involved, emphasizing the number of potential controls. These include gene transcription, gene activation or suppression, activation or suppression of mRNA translation and activation or suppression of signaling pathways. The complexity of these interacting controls presents a challenge to our understanding of the overall coordinated regulation of protein synthesis and degradation and its response to any particular stimulus. Specific examples are used to illustrate regulatory mechanisms, including the ways in which protein metabolism is regulated by the amino acid leucine. In addition to regulation associated with gene expression and post-translational control, the expanding field of epigenetics adds another layer of complexity, including trans-generational responses to nutrient intake, highlighting the potential for long-term impact of nutritional experience on the metabolism of subsequent generations.

(Received July 26 2011)

(Accepted September 19 2011)

Key Words:

  • Protein metabolism;
  • Leucine;
  • Protein synthesis;
  • Protein degradation

Correspondence:

Corresponding author: M. A. McNurlan, email Margaret.McNurlan@stonybrook.edu

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