Abstract: The Shc molecules and the mitochondrial Uncoupling Proteins (UCP) have been proposed to play an important role in Energy Expenditure (EE) and cellular metabolism. We discuss the results of published studies regarding the influence of Shc proteins and UCP on energy metabolism of mice and beef cattle. Additionally, we review the possible association between mitochondrial function from animals classified according to Feed Efficiency (FE). Several studies have been conducted to investigate the role of Shc proteins play in aging and control of Reactive Oxygen Species (ROS) production. Studies have investigated the impact of low Shc levels (ShcKO) in preventing oxidative stress, apoptosis and hyperglycemia. In general, ShcKO is associated with changes in mitochondrial function and EE and protection of tissues against oxidative stress. However, little is known about the role of Shc proteins on energy metabolism in animals fed a high fat diet. In mitochondria, UCP activity provides adaptive thermogenesis, carbon flux maintenance and also protection of cell membranes against oxidative stress caused by ROS. In mitochondrial metabolism, UCP activity (uncoupling) is a paradigm in the context of FE. It may represent a cellular inefficiency but also a reduction in oxidative stress by attenuating mitochondrial ROS production. Thus, studies suggest that mitochondria from less FE animals have greater protein oxidation due to greater basal mitochondrial ROS generation. This increased ROS production could oxidize proteins, causing impaired protein synthesis. However, additional studies are needed to understand the physiological significance of these changes in mitochondrial function and energy metabolism and therefore, the impacts of these molecular mechanisms on animal performance and FE. Changes of very small magnitude in either mitochondrial function or enzyme activities could greatly alter energy metabolism and cause the changes in FE observed in vivo. Most of current biochemical studies are unable to detect the magnitude of the changes.
W.A. Baldassini, B.D. Dauria, J.J. Ramsey, R.H . Branco, S.F.M Bonilha and D.P.D. Lanna, 2018. Key Proteins at the Interface of Bioenergetics and Mitochondrial Function. Journal of Animal and Veterinary Advances, 17: 111-121.