Ribophorin I (RPN1)

Ribophorin I is a highly conserved, dome-shaped transmembrane glycoprotein found exclusively in the membrane of the rough endoplasmic reticulum (ER), where it is a key subunit of the oligosaccharyltransferase (OST) complex[1][2][3][4][5]. Its primary roles include binding the large (60S) ribosomal subunit, facilitating protein translocation into the ER lumen, and selectively presenting substrate proteins for N-linked glycosylation via the OST catalytic core[1][2][3]. Ribophorin I operates as a type I membrane protein, with a significant portion of its structure facing the ER lumen[3][1]. It does not occur in the smooth ER and is only present in eukaryotic cells[1]. The protein is encoded in humans by the RPN1 gene located at chromosome 3q21.3[1]. While essential for correct protein folding and modification, ribophorin I is mainly considered a structural and functional component of cellular machinery rather than a direct therapeutic target. No approved drugs act directly on ribophorin I, and there are no established uses of ribophorin I as a clinical biomarker or pharmacological intervention point. Defects in RPN1 may, however, impact protein quality control and ER homeostasis, potentially contributing to rare congenital disorders[1][2].

Other names

RPN1OST subunit ribophorin IRibophorin-1Ribophorin I subunit of oligosaccharyltransferase