Isoform 2 of Dolichyl-diphosphooligosaccharide--protein glycosyltransferase subunit 2

Isoform 2 of RPN2 (dolichyl-diphosphooligosaccharide–protein glycosyltransferase subunit 2) is a component of the oligosaccharyltransferase complex located in the endoplasmic reticulum, where it catalyzes protein N-glycosylation during co-translational translocation (UniProt: P04844-2). RPN2 plays a central role in protein quality control and proper folding of glycoproteins, with dysfunction implicated in various cellular stress responses.

In Alzheimer's Disease, RPN2 is upregulated in post-mortem brain tissue from affected individuals compared to age-matched controls, with a mean log2 fold-change of 0.33 across subcellular fractions (Chaparral AD proteomics). This upregulation was observed in a TMT-labeled quantitative proteomics study of four subcellular fractions (P2, P3, S2, S3) from human post-mortem AD brain samples. The elevation may reflect compensatory or pathological responses to protein misfolding and aggregation hallmark of Alzheimer's pathology, though the precise functional consequence remains to be determined.