Affinage

RPN2

Dolichyl-diphosphooligosaccharide--protein glycosyltransferase subunit 2 · UniProt P04844

Length
631 aa
Mass
69.3 kDa
Annotated
2026-06-10
37 papers in source corpus 22 papers cited in narrative 22 extracted findings
Cross-family judge vs UniProt: tie faithfulness: 5/5 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

RPN2 is a dual-function protein that operates both as a scaffolding subunit of the 26S proteasome 19S regulatory particle and as a subunit of the ER oligosaccharyltransferase machinery (PMID:22405010, PMID:18724378). Within the 19S particle, its eleven PC repeats fold into a closed α-helical toroid, and the C-terminal residues serve as the docking site that directly recruits the ubiquitin receptor RPN13/ADRM1, with RPN2 also stabilizing the association of RPN10 with the RPN1 solenoid to coordinate ubiquitin-processing factors (PMID:22405010, PMID:22318722, PMID:28442575). Phosphorylation of RPN2 Tyr-950 enhances the affinity of this RPN13 interaction through specific contacts with positively charged RPN13 residues, without conformational change (PMID:31064842). RPN2 contributes to substrate recognition at the proteasome, forming a groove with RPN10 that engages K11/K48-branched ubiquitin chains and participating in ubiquitin-independent degradation of substrates such as ODC [PMID:bio_10.1101_2025.04.07.647569, PMID:bio_10.1101_2025.11.15.688597], and its bipartite NLS directs karyopherin αβ-mediated nuclear import of the proteasomal base (PMID:15210724). Independently, RPN2 mediates N-linked glycosylation of membrane substrates including P-glycoprotein/MDR1, CD63, and EGFR, controlling their cell-surface localization, stability, and signaling; loss of this activity mislocalizes MDR1 and sensitizes chemoresistant cancer cells to therapy (PMID:18724378, PMID:24884960, PMID:29069815).

Mechanistic history

Synthesis pass · year-by-year structured walk · 13 steps
  1. 1991 Low

    Established RPN2/ribophorin II as a rough-ER glycoprotein and placed it on the genetic map, the starting point for its ER-associated functions.

    Evidence in situ hybridization chromosomal mapping to 20q12-q13.1

    PMID:2066112

    Open questions at the time
    • functional role inferred, not demonstrated
    • no link to OST activity established here
    • no proteasomal role identified
  2. 2002 Low

    Predicted the architecture of the RPN1/RPN2 PC-repeat domains as α-helical toroids forming an antechamber, framing the structural hypothesis later tested.

    Evidence computational sequence analysis and molecular modeling

    PMID:12270919

    Open questions at the time
    • no experimental structure in this work
    • function of the proposed antechamber untested
  3. 2004 High

    Answered how proteasomal base complexes reach the nucleus by identifying an RPN2 NLS, showing RPN2 has a localization-determining role beyond scaffolding.

    Evidence NLS deletion mutagenesis and karyopherin pathway/localization assays in yeast

    PMID:15210724

    Open questions at the time
    • human NLS function not directly tested
    • regulation of import not addressed
  4. 2007 Medium

    Showed RPN2 abundance is transcriptionally regulated, linking proteasome assembly to upstream signaling via IEX-1.

    Evidence IEX-1 overexpression in HEK-293 with RT-PCR, promoter luciferase, and proteasome activity assays

    PMID:17107344

    Open questions at the time
    • direct promoter binding by IEX-1 not shown
    • physiological context unclear
  5. 2008 High

    Revealed a chemoresistance function: RPN2 glycosylates MDR1 to maintain its membrane localization, so silencing RPN2 resensitizes resistant tumors.

    Evidence siRNA knockdown with glycosylation, membrane localization, apoptosis assays, and xenografts in breast cancer

    PMID:18724378

    Open questions at the time
    • direct enzymatic glycosyltransferase role versus OST-complex dependence not dissected
    • scope of glycosylated substrates not defined here
  6. 2012 High

    Defined RPN2's molecular role at the 19S particle by mapping direct RPN13 binding to its C-terminus and showing it stabilizes RPN10, organizing ubiquitin-processing factors.

    Evidence quantitative binding assays and Co-IP in yeast plus X-ray crystallography of the PC toroid

    PMID:22318722 PMID:22405010

    Open questions at the time
    • human complex interface not yet resolved
    • functional consequence of RPN13 docking for degradation not measured
  7. 2014 High

    Extended the glycosylation mechanism to CD63, showing RPN2-dependent CD63 glycosylation indirectly controls MDR1 surface display, invasion, and drug resistance.

    Evidence orthogonal RPN2 and CD63 knockdowns with glycosylation, fractionation, invasion, and resistance assays

    PMID:24884960

    Open questions at the time
    • mechanism connecting CD63 glycosylation to MDR1 retention unresolved
    • in vivo validation limited
  8. 2017 High

    Resolved the human RPN2–RPN13 interface at atomic resolution, defining the C-terminal epitope and showing RPN13 binds RPN2, ubiquitin, and UCH37 with independent energetics; also explained why proteasomes outcompete the RA190 inhibitor for RPN13.

    Evidence crystal/NMR structures with SPR, ITC, fluorescence polarization, and cell-based assays using human proteins

    PMID:28442575 PMID:28598414

    Open questions at the time
    • dynamics of RPN13 recruitment in intact proteasome not captured
    • therapeutic exploitation untested in vivo here
  9. 2017 Medium

    Generalized the glycosylation/membrane-localization mechanism to EGFR, linking RPN2 to EGFR/ERK-driven proliferation in colorectal cancer.

    Evidence siRNA knockdown with glycosylation, surface transport, ERK signaling, and xenograft assays

    PMID:29069815

    Open questions at the time
    • direct enzymatic role versus OST dependence not separated
    • single lab
  10. 2019 High

    Showed RPN2 phosphorylation tunes proteasome function by demonstrating that pTyr-950 increases RPN13 affinity through defined electrostatic contacts.

    Evidence 1.76 Å crystal structure of the RPN2(pTyr-950)–RPN13–ubiquitin complex with mutagenesis and biophysical assays

    PMID:31064842

    Open questions at the time
    • kinase responsible for Tyr-950 phosphorylation unidentified
    • physiological trigger and consequence for degradation unknown
  11. 2019 Low

    Reported pro-tumorigenic and differentiation roles for RPN2 via STAT3-axis signaling in HCC and bone marrow stem cells.

    Evidence overexpression/knockdown with western blot, immunofluorescence, invasion, and differentiation assays

    PMID:31481647 PMID:31743606

    Open questions at the time
    • pathway placement rests on correlative western blots
    • direct biochemical link between RPN2 and JAK1/STAT3 not validated
  12. 2022 Medium

    Identified post-translational control of RPN2 itself: lncRNA WEE2-AS1 blocks CUL2-mediated ubiquitination at K322 to stabilize RPN2 and activate PI3K-Akt signaling.

    Evidence MS, RNA pulldown, RIP, Co-IP, ubiquitination assay mapping K322, and pathway analysis in glioblastoma

    PMID:36168628

    Open questions at the time
    • mechanism by which stabilized RPN2 activates PI3K-Akt unclear
    • single lab
  13. 2025 Medium

    Defined the structural basis for branched-chain and ubiquitin-independent substrate recognition, showing RPN2 forms a groove with RPN10 that engages K11/K48-branched ubiquitin and participates in sequential ODC and TXNL1 capture.

    Evidence cryo-EM of human 26S proteasome with branched ubiquitin, ODC, and TXNL1, plus structure-guided mutagenesis and degradation/cell-cycle assays (preprints)

    PMID:bio_10.1101_2024.11.08.622741 PMID:bio_10.1101_2025.01.13.632666 PMID:bio_10.1101_2025.04.07.647569 PMID:bio_10.1101_2025.11.15.688597

    Open questions at the time
    • findings are preprints not yet peer-reviewed
    • RPN2-specific contribution to ODC/TXNL1 degradation inferred from structure
    • in vivo relevance of branched-chain site untested

Open questions

Synthesis pass · forward-looking unresolved questions
  • It remains unresolved whether RPN2's proteasomal scaffolding role and its ER glycosylation role are mechanistically coupled, and which kinases and physiological signals govern RPN2 phosphorylation and stability to switch between these functions.
  • no study bridges OST and proteasome roles
  • upstream regulatory kinases unidentified
  • tissue-specific functional balance unknown

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0016740 transferase activity 3 GO:0060090 molecular adaptor activity 3
Localization
GO:0005783 endoplasmic reticulum 2 GO:0005634 nucleus 1
Pathway
R-HSA-392499 Metabolism of proteins 3 R-HSA-8953854 Metabolism of RNA 3
Partners
CUL2RPN1RPN10RPN13/ADRM1TXNL1
Complex memberships
26S proteasome 19S regulatory particleoligosaccharyltransferase (OST) complex

Evidence

Reading pass · 22 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2008 RPN2 silencing reduced N-glycosylation of P-glycoprotein (MDR1) and decreased its membrane localization, thereby sensitizing docetaxel-resistant breast cancer cells (MCF7-ADR) to docetaxel-induced apoptosis. siRNA knockdown, glycosylation assay, membrane localization analysis, apoptosis assay in breast cancer cells and in vivo xenograft models Nature medicine High 18724378
2014 RPN2 mediates N-glycosylation of tetraspanin CD63; knockdown of RPN2 reduces CD63 glycosylation and delocalizes CD63, which in turn displaces MDR1 from the cell surface and reduces chemoresistance and invasion in breast cancer cells. siRNA knockdown of RPN2 and CD63, glycosylation assay, co-localization/membrane fractionation, Transwell invasion assay, drug resistance assay Molecular cancer High 24884960
2012 Yeast Rpn2 (proteasome subunit) directly binds ubiquitin receptor Rpn13 at its C-terminus, and stabilizes the association of Rpn10 with the central solenoid portion of Rpn1, coordinating multiple ubiquitin-processing factors at the 19S regulatory particle. Biochemical binding assays (association/dissociation constants), Co-IP, affinity measurements in yeast proteasome system The Journal of biological chemistry High 22318722
2012 The eleven PC repeats of Rpn2 form a closed toroidal structure with two concentric rings of α-helices encircling two axial α-helices; the C-terminal 20 residues of Rpn2 serve as the docking site for ubiquitin receptor Rpn13. X-ray crystallography / structural determination of Rpn2 PC domain; binding assays for Rpn13 Structure (London, England : 1993) High 22405010
2004 The bipartite nuclear localization sequence (NLS) of yeast Rpn2 is required for nuclear import of proteasomal base complexes via the karyopherin αβ pathway; deletion of the Rpn2 NLS results in improper nuclear proteasome localization and impaired proteasome function. NLS deletion mutagenesis, karyopherin pathway analysis, nuclear localization assay, proteasome function assay in yeast The Journal of biological chemistry High 15210724
2017 The C-terminal 14 residues of human RPN2 constitute the binding epitope for RPN13/ADRM1's N-terminal PRU domain; crystal structures of the RPN13 PRU domain in complex with RPN2 C-terminal peptides and ubiquitin were determined, and mutagenesis validated the binding interface. RPN2, ubiquitin, and UCH37 bind RPN13 with independent energetics. Crystal structure determination, surface plasmon resonance, fluorescence polarization, mutational analysis using human proteins The Journal of biological chemistry High 28442575
2017 A proline-rich C-terminal extension of hRpn2 stretches across a narrow canyon of the ubiquitin-binding Pru domain of hRpn13, blocking an RA190-binding surface; hRpn13 binds preferentially to hRpn2 and proteasomes over the anticancer compound RA190. RA190 does not affect hRpn13–Uch37 interaction but directly binds and inactivates Uch37. Crystal/NMR structure of hRpn13–hRpn2 complex, biophysical binding assays (SPR, ITC), cell-based assays with hRpn13 deletion in HCT116 cells Nature communications High 28598414
2019 Phosphorylation of RPN2 Tyr-950 (identified in Jurkat cells) enhances RPN2 binding to RPN13; a crystal structure of the RPN2(pTyr-950)–RPN13–ubiquitin complex at 1.76 Å resolution reveals specific interactions with positively charged RPN13 side chains that explain the increased affinity without conformational change. Crystal structure at 1.76 Å, mutagenesis, quantitative binding assays (SPR, fluorescence polarization), phospho-site identification in cells The Journal of biological chemistry High 31064842
2002 Sequence analysis and molecular modeling predict that the PC repeat-containing domains of Rpn1/S2 and Rpn2/S1 adopt an α-helical toroid architecture with a central pore, proposed to form an antechamber for unfolded substrates ahead of the ATPase ring. Computational sequence analysis, molecular modeling The Journal of biological chemistry Low 12270919
2017 RPN2 knockdown reduced glycosylation of EGFR, decreased EGFR cell-surface transport, and attenuated EGFR/ERK signaling, thereby inhibiting colorectal cancer cell proliferation in vitro and in vivo. siRNA knockdown, glycosylation assay, EGFR cell-surface transport assay, ERK signaling analysis, in vitro proliferation and in vivo xenograft Oncotarget Medium 29069815
2007 IEX-1 (immediate early gene-X-1) reduces expression of proteasome subunits S1/Rpn2 and S5a/Rpn10 at the transcriptional level (interference with S5a promoter activity), leading to decreased 26S proteasome assembly and activity in HEK-293 cells. Overexpression of IEX-1 in HEK-293 cells, quantitative RT-PCR, luciferase promoter assay, cycloheximide/actinomycin D chase, 26S proteasome activity assay The Biochemical journal Medium 17107344
2019 RPN2 promotes hepatocellular carcinoma cell invasion by activating NF-κB p65 to upregulate MMP-9, and phosphorylated RPN2 activates STAT3, which also upregulates MMP-9 and promotes invasion. RPN2 overexpression and knockdown, western blot for MMP-9/NF-κB/STAT3, immunofluorescence, invasion assays in HCC cells Aging Low 31481647
2018 RPN2 knockdown in colon carcinoma cells reduced cell viability, increased apoptosis (caspase-3 upregulation), arrested cell cycle at G0/G1 (cyclin D1 reduction), and inhibited migration/invasion by regulating E-cadherin, MMP-2, and TIMP-2; STAT3 and JAK2 phosphorylation were reduced by RPN2 siRNA. siRNA knockdown, flow cytometry, Transwell assay, western blot, RT-PCR in colon cancer cell lines Oncology reports Low 29749494
2020 RPN2 overexpression suppresses radiosensitivity of glioma cells by activating STAT3 signaling, which upregulates MCL1; depletion of RPN2 in radiation-resistant GBM cells sensitizes them to radiation-induced apoptosis. RPN2 overexpression/knockdown, radiation resistance assay, western blot for STAT3/MCL1, apoptosis assay in GBM cell lines Molecular medicine (Cambridge, Mass.) Low 32404045
2022 The lncRNA WEE2-AS1 promotes RPN2 protein stabilization by preventing CUL2-mediated ubiquitination of RPN2 at K322, thereby activating the PI3K-Akt signaling pathway in glioblastoma cells. Mass spectrometry, RNA pulldown, RIP assay, Co-IP, luciferase reporter, ubiquitination assay identifying K322 as the ubiquitination site, PI3K-Akt pathway analysis Theranostics Medium 36168628
2019 RPN2 overexpression promotes osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs) by inducing JAK1 ubiquitination and activating JAK1/STAT3 signaling, promoting nuclear translocation of STAT3; depletion of JAK1 partially rescues the differentiation defect caused by RPN2 silencing. RPN2 overexpression/knockdown, alkaline phosphatase activity, western blot for JAK1/STAT3 phosphorylation and nuclear translocation, epistasis with JAK1 depletion, hBMSC differentiation assay FEBS open bio Low 31743606
2025 Cryo-EM structures of the human 26S proteasome bound to K11/K48-branched ubiquitin chains reveal a novel K11-linked ubiquitin binding site at the groove formed by RPN2 and RPN10, in addition to the canonical K48-linkage binding site; RPN2 recognizes alternating K11-K48 linkages through a conserved motif similar to the K48-specific T1 binding site of RPN1. Cryo-EM structural determination of human 26S proteasome–branched ubiquitin chain complex bioRxiv (preprint)preprint Medium bio_10.1101_2025.01.13.632666
2025 High-resolution cryo-EM structures of the human 26S proteasome bound to K48-tetraubiquitin and K11/K48-branched chains reveal that K11 branches engage a cleft formed between RPN2 and RPN10; structure-guided mutagenesis confirms these binding modes are essential for efficient substrate degradation and cell cycle progression. Cryo-EM, structure-guided mutagenesis, substrate degradation assay, cell cycle analysis bioRxiv (preprint)preprint Medium bio_10.1101_2025.04.07.647569
2025 Eleven cryo-EM structures of the human 26S proteasome complexed with ODC reveal that Rpn2's PC domain participates in a multivalent, sequential recognition process for ubiquitin-independent ODC degradation, following initial engagement of the Rpn10 vWA domain and Rpt4/5 coiled-coil. Cryo-EM (11 structures capturing degradation intermediates), structural analysis of proteasome–ODC complex bioRxiv (preprint)preprint Medium bio_10.1101_2025.11.15.688597
2024 Cryo-EM structure of TXNL1 bound to the 19S regulatory particle reveals direct interactions between TXNL1 and PSMD1/Rpn2 (as well as Rpn10 and Rpn11), establishing the structural basis for ubiquitin-independent degradation of TXNL1 upon oxidative stress. Cryo-EM structural determination of TXNL1–19S proteasome complex bioRxiv (preprint)preprint Low bio_10.1101_2024.11.08.622741
2021 RPN2 overexpression in T lymphocytes inhibited apoptosis and IL-4 expression and promoted proliferation and activation, establishing a functional role for RPN2 in T lymphocyte growth and activation. Lentivirus-mediated RPN2 overexpression in T lymphocytes, flow cytometry for apoptosis and proliferation, cytokine measurement (IL-4), activation assays Gene Low 34740730
1991 RPN2 (ribophorin II) was chromosomally mapped to human chromosome 20q12-q13.1 by in situ hybridization; the protein was described as a glycoprotein spanning the rough endoplasmic reticulum, proposed to play a role in translocation or maintenance of RER. In situ hybridization chromosomal mapping Human genetics Low 2066112

Source papers

Stage 0 corpus · 37 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2008 RPN2 gene confers docetaxel resistance in breast cancer. Nature medicine 135 18724378
2014 RPN2-mediated glycosylation of tetraspanin CD63 regulates breast cancer cell malignancy. Molecular cancer 104 24884960
2012 Rpn1 and Rpn2 coordinate ubiquitin processing factors at proteasome. The Journal of biological chemistry 98 22318722
2017 Structure of the Rpn13-Rpn2 complex provides insights for Rpn13 and Uch37 as anticancer targets. Nature communications 73 28598414
2002 What curves alpha-solenoids? Evidence for an alpha-helical toroid structure of Rpn1 and Rpn2 proteins of the 26 S proteasome. The Journal of biological chemistry 64 12270919
2019 CircNFIX promotes progression of glioma through regulating miR-378e/RPN2 axis. Journal of experimental & clinical cancer research : CR 59 31888753
2004 The bipartite nuclear localization sequence of Rpn2 is required for nuclear import of proteasomal base complexes via karyopherin alphabeta and proteasome functions. The Journal of biological chemistry 57 15210724
2012 The structure of the 26S proteasome subunit Rpn2 reveals its PC repeat domain as a closed toroid of two concentric α-helical rings. Structure (London, England : 1993) 55 22405010
2018 Phytoplasma effector SWP1 induces witches' broom symptom by destabilizing the TCP transcription factor BRANCHED1. Molecular plant pathology 49 30047227
2017 Structure and energetics of pairwise interactions between proteasome subunits RPN2, RPN13, and ubiquitin clarify a substrate recruitment mechanism. The Journal of biological chemistry 47 28442575
2020 RPN2 is targeted by miR-181c and mediates glioma progression and temozolomide sensitivity via the wnt/β-catenin signaling pathway. Cell death & disease 37 33087705
2019 RPN2 promotes metastasis of hepatocellular carcinoma cell and inhibits autophagy via STAT3 and NF-κB pathways. Aging 36 31481647
2022 The N6-methyladenosine-mediated lncRNA WEE2-AS1 promotes glioblastoma progression by stabilizing RPN2. Theranostics 33 36168628
2023 YTHDF1 Promotes Bladder Cancer Cell Proliferation via the METTL3/YTHDF1-RPN2-PI3K/AKT/mTOR Axis. International journal of molecular sciences 27 37108067
2015 Integrated transcriptional profiling and genomic analyses reveal RPN2 and HMGB1 as promising biomarkers in colorectal cancer. Cell & bioscience 27 26388988
2012 RPN2 expression predicts response to docetaxel in oesophageal squamous cell carcinoma. British journal of cancer 27 22955852
2018 Downregulation of RPN2 induces apoptosis and inhibits migration and invasion in colon carcinoma. Oncology reports 25 29749494
2017 RPN2 promotes colorectal cancer cell proliferation through modulating the glycosylation status of EGFR. Oncotarget 25 29069815
2015 The expression and clinical significance of ribophorin II (RPN2) in human breast cancer. Pathology international 25 25881688
2018 MicroRNA-128 targeting RPN2 inhibits cell proliferation and migration through the Akt-p53-cyclin pathway in colorectal cancer cells. Oncology letters 19 30546426
2020 Circ_0046599 Promotes the Development of Hepatocellular Carcinoma by Regulating the miR-1258/RPN2 Network. Cancer management and research 16 32801909
2018 RPN2 is effective biomarker to predict the outcome of combined chemotherapy docetaxel and cisplatin for advanced gastric cancer. Oncotarget 15 29632637
2007 Immediate early gene-X1 interferes with 26 S proteasome activity by attenuating expression of the 19 S proteasomal components S5a/Rpn10 and S1/Rpn2. The Biochemical journal 15 17107344
1991 Mapping of the ribophorin II (RPN II) gene to human chromosome 20q12-q13.1 by in-situ hybridization. Human genetics 14 2066112
2023 RPN2 in cancer: An overview. Gene 12 36621657
2020 Overexpression of RPN2 suppresses radiosensitivity of glioma cells by activating STAT3 signal transduction. Molecular medicine (Cambridge, Mass.) 12 32404045
2019 Phosphorylation of Tyr-950 in the proteasome scaffolding protein RPN2 modulates its interaction with the ubiquitin receptor RPN13. The Journal of biological chemistry 12 31064842
2021 circ_SMAD2 regulate colorectal cancer cells proliferation through targeting miR-1258/RPN2 signaling pathway. Journal of Cancer 11 33613755
2020 Lysine in Combination With Estradiol Promote Dissemination of Estrogen Receptor Positive Breast Cancer via Upregulation of U2AF1 and RPN2 Proteins. Frontiers in oncology 11 33330095
2019 Overexpression of RPN2 promotes osteogenic differentiation of hBMSCs through the JAK/STAT3 pathway. FEBS open bio 11 31743606
2020 MicroRNA‑422a functions as a tumor suppressor in glioma by regulating the Wnt/β‑catenin signaling pathway via RPN2. Oncology reports 10 33000268
2022 circTOP2A functions as a ceRNA to promote glioma progression by upregulating RPN2. Cancer science 5 36227125
2022 Sevoflurane represses the progression of glioma by the regulation of circ_0037655/miR-130a-5p/RPN2 axis. Metabolic brain disease 4 35032276
2024 Mutation in the 26S proteasome regulatory subunit rpn2 gene in Plasmodium falciparum confers resistance to artemisinin. Frontiers in cellular and infection microbiology 3 38404287
2024 Leu promotes C2C12 cell differentiation by regulating the GSK3β/β-catenin signaling pathway through facilitating the interaction between SESN2 and RPN2. Journal of the science of food and agriculture 3 38551359
2021 Epigenetically-regulated RPN2 gene influences lymphocyte activation and is involved in pathogenesis of rheumatoid arthritis. Gene 1 34740730
2025 S100A16 knockdown reduces RPN2 expression and inhibits β-catenin/TCF signaling, leading to suppressed metastasis in cervical cancer cells. Biochimica et biophysica acta. Molecular cell research 0 40907797

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