Ablation of sarcolipin decreases the energy requirements for Ca2+ transport by sarco(endo)plasmic reticulum Ca2+-ATPases in resting skeletal muscle.

Abstract The purpose of this study was to examine the effects of sarcolipin (SLN) on sarco(endo) plasmic reticulum Ca 2+ -ATPase (SERCA pump) energetics in vivo and resting skeletal muscle metabolic rate. Using SLN knockout ( Sln −/− ) mice we show that SLN ablation increases the transport stoichiometry of SERCA pumps (Ca 2+ uptake/Ca 2+ -ATPase activity) and decreases the relative contribution of SERCA pumps to resting oxygen consumption ( VO 2 ) in soleus without affecting soleus or whole body VO 2 . These data suggest that the lower energy requirements for Ca 2+ cycling in resting skeletal muscle of Sln −/− mice do not impact significantly either skeletal muscle or whole body metabolic rate.