RPN1

Existing Annotations Review

GO Term	Evidence	Action	Reason
GO:0006487 protein N-linked glycosylation	IBA GO_REF:0000033	ACCEPT	Summary: Phylogenetic (IBA) propagation of the core biological process for the OST subunit family. RPN1 is an OST subunit and OST catalyzes protein N-linked glycosylation; this is a correct core process for the gene, well supported experimentally.
GO:0008250 oligosaccharyltransferase complex	IBA GO_REF:0000033	ACCEPT	Summary: Phylogenetic (IBA) inference that RPN1 (ortholog of yeast Ost1p) is part of the OST complex. This is the defining core complex membership of RPN1 and is directly supported by biochemical purification and cryo-EM structures.
GO:0005783 endoplasmic reticulum	IEA GO_REF:0000117	KEEP AS NON CORE	Summary: ARBA electronic annotation to endoplasmic reticulum. RPN1 is a bona fide ER-resident protein, but this is a less-specific parent of the endoplasmic reticulum membrane term that better captures its type-I membrane topology. Correct but general.
GO:0005789 endoplasmic reticulum membrane	IEA GO_REF:0000044	ACCEPT	Summary: Subcellular-location IEA to ER membrane, the correct core localization of this single-pass type I ER membrane protein. Redundant with experimental/ISS support but a correct core CC.
GO:0009101 glycoprotein biosynthetic process	IEA GO_REF:0000002	MODIFY	Summary: InterPro2GO electronic annotation. This is a correct but less-specific parent of protein N-linked glycosylation, which is the informative process term for OST subunits. Proposed replacements: protein N-linked glycosylation
GO:0016020 membrane	IEA GO_REF:0000002	MARK AS OVER ANNOTATED	Summary: InterPro2GO electronic annotation to the generic membrane term. True (RPN1 is an integral membrane protein) but uninformative relative to endoplasmic reticulum membrane.
GO:0042470 melanosome	IEA GO_REF:0000044	MARK AS OVER ANNOTATED	Summary: Subcellular-location IEA mapped from the UniProt melanosome annotation, which itself derives from melanosome-fraction proteomics. Melanosomes are lysosome-related organelles that share many contaminating ER proteins; this is not a genuine functional compartment for RPN1.
GO:0005515 protein binding	IPI PMID:19167329 Cotranslational and posttranslational N-glycosylation of pol...	MARK AS OVER ANNOTATED	Summary: IPI capturing an RPN1 interaction with the catalytic OST subunit STT3B (Q8TCJ2). The paper shows ribophorin I depletion co-reduces STT3A and STT3B and lowers OST activity, consistent with RPN1 being in the same complex. "Protein binding" is uninformative as a molecular function; the informative modeling is OST complex membership and contribution to its glycotransferase activity. Supporting Evidence: PMID:19167329 ribophorin I caused a 2- to 3-fold reduction of both STT3A and STT3B
GO:0005515 protein binding	IPI PMID:25416956 A proteome-scale map of the human interactome network.	MARK AS OVER ANNOTATED	Summary: High-throughput interactome (Y2H) IPI to SGTA/UBQLN1. Bare "protein binding" is uninformative; retain as non-core interaction evidence, better modeled via specific complex/function terms rather than as a molecular function.
GO:0005515 protein binding	IPI PMID:30021884 Histone Interaction Landscapes Visualized by Crosslinking Ma...	MARK AS OVER ANNOTATED	Summary: Crosslinking-MS IPI to OST partners including STT3A, STT3B and malectin (MLEC). Consistent with OST membership and the RPN1-malectin quality-control association, but "protein binding" itself is uninformative as an MF.
GO:0005515 protein binding	IPI PMID:31515488 Extensive disruption of protein interactions by genetic vari...	MARK AS OVER ANNOTATED	Summary: Interactome-variant screen IPI to SGTA/UBQLN1. Uninformative bare protein-binding MF; keep as non-core interaction support.
GO:0005515 protein binding	IPI PMID:31831667 Cryo-electron microscopy structures of human oligosaccharylt...	MARK AS OVER ANNOTATED	Summary: IPI derived from the OST cryo-EM study, here recorded against malectin (MLEC). The paper itself establishes RPN1 as an OST subunit; the interaction is real but "protein binding" is uninformative, better captured by complex membership.
GO:0005515 protein binding	IPI PMID:32296183 A reference map of the human binary protein interactome.	MARK AS OVER ANNOTATED	Summary: Binary interactome (HuRI) IPI to SGTA/CAMLG/KRTAP1-3. High-throughput binary hits; uninformative as a molecular function.
GO:0005515 protein binding	IPI PMID:32707033 Kinase Interaction Network Expands Functional and Disease Ro...	MARK AS OVER ANNOTATED	Summary: Kinase-interaction network IPI to POMK. Uninformative bare protein-binding MF; keep as non-core.
GO:0005515 protein binding	IPI PMID:35271311 OpenCell: Endogenous tagging for the cartography of human ce...	MARK AS OVER ANNOTATED	Summary: OpenCell endogenous-tagging interactome IPI to STT3A, STT3B and malectin. Recapitulates OST membership and the malectin association; "protein binding" remains uninformative as an MF.
GO:0005789 endoplasmic reticulum membrane	NAS PMID:31831667 Cryo-electron microscopy structures of human oligosaccharylt...	ACCEPT	Summary: ComplexPortal NAS placing the OST complex (and RPN1) in the ER membrane, consistent with the cryo-EM study. Correct core localization.
GO:0006487 protein N-linked glycosylation	IDA PMID:31831667 Cryo-electron microscopy structures of human oligosaccharylt...	ACCEPT	Summary: IDA (ComplexPortal) for the OST complex catalyzing N-linked glycosylation, based on the cryo-EM structures of OST-A/OST-B with RPN1 as an assigned subunit. Correct core process.
GO:0006487 protein N-linked glycosylation	NAS PMID:31831667 Cryo-electron microscopy structures of human oligosaccharylt...	ACCEPT	Summary: ComplexPortal NAS duplicate of the core N-linked glycosylation process. Correct; redundant with the IDA on the same reference.
GO:0008250 oligosaccharyltransferase complex	IPI PMID:31831667 Cryo-electron microscopy structures of human oligosaccharylt...	ACCEPT	Summary: IPI (ComplexPortal) for RPN1 as a component of the OST complex, from the cryo-EM structures. Defining core complex membership.
GO:0008250 oligosaccharyltransferase complex	NAS PMID:31831667 Cryo-electron microscopy structures of human oligosaccharylt...	ACCEPT	Summary: ComplexPortal NAS duplicate of OST complex membership. Correct core complex.
GO:0005783 endoplasmic reticulum	IDA GO_REF:0000052	KEEP AS NON CORE	Summary: HPA immunofluorescence IDA to endoplasmic reticulum. Correct experimental localization, though the more specific ER membrane term better captures RPN1's topology.
GO:0005829 cytosol	IDA GO_REF:0000052	MARK AS OVER ANNOTATED	Summary: HPA immunofluorescence IDA to cytosol. RPN1 is an integral ER membrane protein with only a short cytoplasmic tail; a bulk cytosolic localization is not its functional compartment and likely reflects diffuse or non-specific staining. Retained per policy (experimental IDA) but flagged as an over-annotation rather than removed.
GO:0005789 endoplasmic reticulum membrane	ISS GO_REF:0000024	ACCEPT	Summary: ISS from the mouse ortholog (E2RQ08) to ER membrane, the correct core localization of this type I ER membrane protein.
GO:0042470 melanosome	EXP PMID:12643545 Proteomic analysis of early melanosomes: identification of n...	MARK AS OVER ANNOTATED	Summary: EXP from melanosome-fraction proteomics. RPN1 was detected by mass spectrometry in melanosome preparations, but as an abundant ER protein it is a likely ER contaminant of lysosome-related-organelle fractions rather than a genuine melanosomal resident. Retained (experimental) but marked as over-annotation; not a core function. Supporting Evidence: PMID:12643545 confirmed the presence of 6 novel melanosomal
GO:0042470 melanosome	EXP PMID:17081065 Proteomic and bioinformatic characterization of the biogenes...	MARK AS OVER ANNOTATED	Summary: EXP from a second melanosome proteomics/bioinformatics study. Same interpretation: an ER protein co-purifying with melanosome fractions rather than a bona fide melanosomal function. Supporting Evidence: PMID:17081065 melanosome proteomes at various developmental stages by tandem mass
GO:0160226 oligosaccharyltransferase complex A	IDA PMID:31831667 Cryo-electron microscopy structures of human oligosaccharylt...	ACCEPT	Summary: IDA that RPN1 is a subunit of the cotranslational OST-A (STT3A) complex, from the cryo-EM structure. More specific than the generic OST complex term and a correct core annotation; the study shows RPN1 forms a ribosome-binding four-helix bundle specifically in OST-A. Supporting Evidence: PMID:31831667 In OST-A, interactions with TMEM258 and STT3A allow ribophorin-I to form a four-helix bundle that can bind to a translating ribosome
GO:0160226 oligosaccharyltransferase complex A	IDA PMID:36697828 Visualization of translation and protein biogenesis at the E...	ACCEPT	Summary: IDA for RPN1 as an OST-A subunit from an in situ cryo-ET study of translation and protein biogenesis at the ER membrane. Correct core complex membership. Supporting Evidence: PMID:36697828 Visualization of translation and protein biogenesis at the ER membrane
GO:0160226 oligosaccharyltransferase complex A	IDA PMID:38670073 Positive selection CRISPR screens reveal a druggable pocket ...	ACCEPT	Summary: IDA for RPN1 as an OST-A subunit from a CRISPR/cryo-EM study of the STT3A complex and its druggable pocket. Correct core complex membership. Supporting Evidence: PMID:38670073 STT3A, the catalytic subunit of OST-A
GO:0160227 oligosaccharyltransferase complex B	IDA PMID:31831667 Cryo-electron microscopy structures of human oligosaccharylt...	ACCEPT	Summary: IDA that RPN1 is also a subunit of the post-translocational OST-B (STT3B) complex, from the cryo-EM structure. RPN1 is a shared subunit of both OST forms; correct core annotation. Supporting Evidence: PMID:31831667 whereas the equivalent region is disordered in OST-B
GO:0005515 protein binding	IPI PMID:27974209 TMEM258 Is a Component of the Oligosaccharyltransferase Comp...	MARK AS OVER ANNOTATED	Summary: IPI to TMEM258 (P61165), an OST core subunit that forms STT3A "subcomplex 1" together with RPN1. The interaction is biologically real and supports OST membership, but bare "protein binding" is uninformative as an MF. Supporting Evidence: PMID:27974209 TMEM258 is a required component of the oligosaccharyltransferase complex and is essential for N-linked protein glycosylation
GO:0006487 protein N-linked glycosylation	IDA PMID:9642163 Interleukin-2 induces N-glycosylation in T-cells: characteri...	ACCEPT	Summary: IDA from biochemical purification of human lymphocyte OST, in which ribophorin I was one of the predominant N-terminally sequenced subunits of the N-glycosylation enzyme preparation. Directly supports RPN1 involvement in protein N-linked glycosylation. Core process. Supporting Evidence: PMID:9642163 the proteins as ribophorin I, ribophorin II (doublet), and a 50-kDa homologue of Wbp1
GO:0008250 oligosaccharyltransferase complex	IDA PMID:9642163 Interleukin-2 induces N-glycosylation in T-cells: characteri...	ACCEPT	Summary: IDA that RPN1 co-purifies as a subunit of the human OST enzyme. Directly supports OST complex membership. Defining core complex. Supporting Evidence: PMID:9642163 the proteins as ribophorin I, ribophorin II (doublet), and a 50-kDa homologue of Wbp1
GO:0016020 membrane	HDA PMID:19946888 Defining the membrane proteome of NK cells.	MARK AS OVER ANNOTATED	Summary: High-throughput MS membrane-proteome dataset (NK-cell line). True but generic; the specific ER membrane localization is the informative term.
GO:0003723 RNA binding	HDA PMID:22658674 Insights into RNA biology from an atlas of mammalian mRNA-bi...	MARK AS OVER ANNOTATED	Summary: From a global mRNA-interactome-capture (UV crosslinking) proteomics screen in HeLa. RPN1 is an ER-membrane glycosylation subunit with no sequence-specific RNA-binding function; its cytoplasmic four-helix bundle contacts the translating ribosome, which plausibly accounts for crosslinking to mRNA in such screens. Not a bona fide molecular function. Retained per policy (experimental HDA) but marked as over-annotation rather than removed. Supporting Evidence: PMID:22658674 We identify 860 proteins that qualify as RBPs by biochemical and statistical criteria
GO:0005515 protein binding	IPI PMID:22988243 Malectin forms a complex with ribophorin I for enhanced asso...	MARK AS OVER ANNOTATED	Summary: IPI to malectin (MLEC, Q14165). RPN1 forms a stable complex with the ER lectin malectin, enhancing association with misfolded glycoproteins and implicating RPN1 in glycoprotein quality control. Biologically informative interaction, but bare "protein binding" is not an informative MF; the interaction is best modeled as a specific complex/adapter relationship. Supporting Evidence: PMID:22988243 malectin formed a stable complex with an endoplasmic reticulum-resident transmembrane protein, ribophorin I
GO:0006487 protein N-linked glycosylation	IMP PMID:17264154 Ribophorin I acts as a substrate-specific facilitator of N-g...	ACCEPT	Summary: IMP from RNAi depletion of ribophorin I, which dramatically reduced N-glycosylation of selected membrane proteins. Establishes RPN1's role as a substrate-specific facilitator of N-glycosylation. Strong support for the core process. Supporting Evidence: PMID:17264154 ribophorin I dramatically enhances the N-glycosylation of selected membrane proteins
GO:0005789 endoplasmic reticulum membrane	TAS Reactome:R-HSA-446209	ACCEPT	Summary: Reactome TAS placing RPN1 in the ER membrane (N-glycan transfer reaction). Correct core localization.
GO:0005789 endoplasmic reticulum membrane	TAS Reactome:R-HSA-9694793	ACCEPT	Summary: Reactome TAS (viral spike protein N-glycosylation reaction) placing RPN1 in the ER membrane. Correct localization; the viral-substrate pathway context is incidental.
GO:0005789 endoplasmic reticulum membrane	TAS Reactome:R-HSA-9816276	ACCEPT	Summary: Reactome TAS (CDH1 N-glycosylation reaction) placing RPN1 in the ER membrane. Correct localization.
GO:0005789 endoplasmic reticulum membrane	TAS Reactome:R-HSA-9918962	ACCEPT	Summary: Reactome TAS (viral E protein N-glycosylation reaction) placing RPN1 in the ER membrane. Correct localization.
GO:0005789 endoplasmic reticulum membrane	TAS Reactome:R-HSA-9918988	ACCEPT	Summary: Reactome TAS (viral pre-M N-glycosylation reaction) placing RPN1 in the ER membrane. Correct localization.
GO:0005789 endoplasmic reticulum membrane	TAS Reactome:R-HSA-9919011	ACCEPT	Summary: Reactome TAS (viral pre-NS1 N-glycosylation reaction) placing RPN1 in the ER membrane. Correct localization.
GO:0005789 endoplasmic reticulum membrane	TAS Reactome:R-HSA-9931286	ACCEPT	Summary: Reactome TAS (CD274/PD-L1 N-glycosylation reaction) placing RPN1 in the ER membrane. Correct localization.
GO:0004579 dolichyl-diphosphooligosaccharide-protein glycotransferase activity	TAS PMID:15835887 Proteomic analysis of mammalian oligosaccharyltransferase re...	ACCEPT	Summary: TAS with the contributes_to qualifier for the OST catalytic activity. This is the correct way to model a non-catalytic subunit: RPN1 is not itself the catalyst (STT3A/STT3B are) but contributes to the complex's dolichyl-diphosphooligosaccharide-protein glycotransferase activity. Core molecular function contribution. Supporting Evidence: PMID:15835887 All known mammalian OST subunits (STT3-A, ribophorin I, ribophorin II, OST48, and DAD1) were present in all complexes

Gene Description

Existing Annotations Review

Core Functions

Non-catalytic subunit of the oligosaccharyltransferase (OST) complex that contributes to the complex's dolichyl-diphosphooligosaccharide-protein glycotransferase activity, the en bloc transfer of Glc3Man9GlcNAc2 from dolichol-pyrophosphate onto asparagine sequons.

Participates in protein N-linked glycosylation as a substrate-specific facilitator, presenting and enhancing glycosylation of selected nascent chains by the catalytic STT3 subunits; in the cotranslational OST-A complex its cytoplasmic four-helix bundle can engage the translating ribosome.

References

📚 Additional Documentation

Notes

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