The N-terminal region of this group of proteins is required for correct folding of the ER UDP-Glc: glucosyltransferase. These proteins selectively reglucosylates unfolded glycoproteins, thus providing quality control for protein transport out of the ER. Unfolded, denatured glycoproteins are substantially better substrates for glucosylation by this enzyme than are the corresponding native proteins. This protein and transient glucosylation may be involved in monitoring and/or assisting the folding and assembly of newly made glycoproteins, in order to identify glycoproteins that need assistance in folding from chaperones