Your liver switches from producing glucose to storing it after you eat. A cellular signaling pathway known as the unfolded protein response (UPR) is transiently activated at the same time, but it is not clear how this pathway contributes to the liver's metabolic switch.
In this issue of the Journal of Clinical Investigation, researchers led by Phillip Scherer at the University of Texas Southwestern Medical Center report that activation of the UPR triggers the expression of Xbp1s, a protein that regulates genes needed for the metabolic switch. Scherer and colleagues found that they could induce changes in liver metabolism just by increasing expression of Xbps1. These results suggest that Xbps1 could play a role in metabolic disease.