Faculty Opinions recommendation of Interdomain conformational flexibility underpins the activity of UGGT, the eukaryotic glycoprotein secretion checkpoint.
UGGT (UDP-Glc:glycoprotein glucosyltransferase) is a key enzyme in the ER glycoprotein folding cycle (calnexin/calreticulin sycle), which serves as a "folding sensor in the ER". Intriguingly, this enzyme specifically recognizes incompletely folded glycoproteins and converts them to mono-glucosylated forms. Despite its importance, how it detects the folding status of glycoproteins has been unclear. This article solves the crystal structures of this enzyme. In combination with cryo-electron microscopy analysis, the study revealed an interdomain conformational flexibility that would explain the folding sensing property of UGGT. For further reading, please see {1}.