UDP-glucose:glycoprotein glucosyltransferase 1

UDP-glucose:glycoprotein glucosyltransferase 1 (UGGT1) is an endoplasmic reticulum resident enzyme that catalyzes protein quality control through reglucosylation of glycoproteins with minor folding defects (UniProt: Q9NYU2). By adding single N-glycans near misfolded regions, UGGT1 marks substrates for recognition by calreticulin, enabling either ER recycling and refolding or proteasomal degradation. This function is central to ER proteostasis and prevents accumulation of malfolded proteins.

UGGT1 operates within the secretory pathway's quality control machinery, a system increasingly implicated in neurodegenerative disease pathogenesis. The protein's role in ER-associated degradation (ERAD) and protein folding surveillance positions it at an interface between cellular stress responses and protein aggregation disorders.

In Alzheimer's disease, UGGT1 shows evidence of upregulation in post-mortem AD brain tissue relative to age-matched controls, with a mean log2 fold-change of 0.50 (Chaparral AD proteomics). This elevation may reflect compensatory activation of ER quality control mechanisms in response to proteostatic stress associated with amyloid and tau pathology, though the functional significance of this upregulation requires further investigation.