RNF167

RNF167 is a transmembrane RING-type E3 ubiquitin ligase resident in endosomes and lysosomes that controls membrane-receptor abundance, organelle dynamics, nutrient signaling, and innate immunity through substrate-specific ubiquitination (PMID:23129617, PMID:27808481, PMID:33594058). Its catalytic activity requires an intact RING domain, while its protease-associated (PA) domain governs endosomal/lysosomal localization; tumor-derived PA mutations leave the enzyme catalytically active but mislocalized and unable to reach substrates (PMID:24387786). RNF167 builds ubiquitin chains by partnering with E2 enzymes UBE2D1 and UBE2N, where an initiating E2 primes the substrate and UBE2N elongates the chain, as reconstituted for the AMPA receptor subunit GluA2 to drive activity-dependent reduction of surface AMPA receptors and synaptic currents (PMID:23129617, PMID:33650289). The ligase shapes the endolysosomal system by ubiquitinating Arl8B at K141 to control lysosome positioning and by ubiquitinating GTP-bound, membrane-anchored Rab7 to maintain its membrane localization and regulate endosomal vesicle size (PMID:27808481, PMID:35887194). RNF167 is a node in mTORC1 control, acting bidirectionally: it drives K29-linked degradation of the arginine sensor CASTOR1 (enhanced by AKT-mediated CASTOR1 S14 phosphorylation) to activate mTORC1, and it ubiquitinates Sestrin2 to promote its GATOR2 interaction and inhibit mTORC1, an event reversed by the deubiquitinase STAMBPL1 (PMID:33594058, PMID:35114100). In immune and inflammatory signaling it attaches K33-linked chains to Tollip at K235 to enable suppression of TNF-α-induced NF-κB and MAPK activation, and it dampens type I interferon responses by directing RIG-I/MDA5 to dual degradation routes—K6-linked CARD ubiquitination read by p62 for selective autophagy and K11-linked CTD ubiquitination for proteasomal turnover (PMID:37410058, PMID:39994288).

1. 2012 High

   Established RNF167 as a transmembrane RING E3 ligase that acts at the neuronal surface to control synaptic strength, defining its first physiological substrate.

   Evidence Transmembrane RING E3 screen with RING-dead mutant and shRNA in hippocampal neurons, surface AMPAR assays, electrophysiology

   PMID:23129617

   Open questions at the time

   • Ubiquitination site on AMPAR subunits not mapped
   • E2 partners and chain linkage not yet defined
2. 2014 Medium

   Separated the catalytic and targeting modules of RNF167, showing the RING domain is required for ligase activity while the PA domain dictates endosomal localization, and linking PA mutations to cancer-associated mislocalization.

   Evidence Tumor mutation analysis with RING and PA domain mutants, in vitro ligase assays, subcellular localization

   PMID:24387786

   Open questions at the time

   • How the PA domain achieves membrane targeting at the molecular level unresolved
   • Functional consequence of mislocalization on specific substrates not tested
3. 2016 High

   Extended RNF167 function to organelle dynamics by identifying Arl8B as a substrate whose K141 ubiquitination controls lysosome positioning and endocytic trafficking.

   Evidence BioID substrate screen, in vitro ubiquitination, K141R rescue, lysosome positioning readouts

   PMID:27808481

   Open questions at the time

   • Chain linkage type on Arl8B not specified
   • Upstream signals regulating this event unknown
4. 2021 High

   Defined the enzymatic logic of RNF167 chain assembly, showing an initiating E2 primes the substrate and UBE2N elongates the chain, validated for GluA2 and confirmed in neurons.

   Evidence In vitro reconstitution with defined E2s, kinetic binding measurements, GluA2 polyubiquitination assay, UBE2N inhibition in neurons

   PMID:33650289

   Open questions at the time

   • Identity of the priming E2 not fully resolved
   • Whether the same E2 logic applies to all substrates untested
5. 2021 High

   Connected RNF167 to mTORC1 activation by showing AKT-phosphorylated CASTOR1 is degraded via K29-linked ubiquitination, providing an arginine-independent route to mTORC1 activity in cancer.

   Evidence Co-IP, K29 linkage-specific ubiquitination assays, S14 phospho-mutagenesis, AKT kinase assay, xenograft models

   PMID:33594058

   Open questions at the time

   • Whether CASTOR1 turnover occurs at the lysosomal membrane unclear
   • Counteracting deubiquitinase not identified
6. 2022 High

   Revealed RNF167 as a bidirectional mTORC1 regulator, ubiquitinating Sestrin2 to promote GATOR2 binding and inhibit mTORC1, opposed by the deubiquitinase STAMBPL1 under leucine control.

   Evidence E3 identification, Co-IP of ubiquitinated Sestrin2 with GATOR2, STAMBPL1 KO/correction, blocking peptide, xenografts

   PMID:35114100

   Open questions at the time

   • How leucine availability is sensed upstream of this axis unclear
   • Reconciliation of opposing CASTOR1/Sestrin2 effects on mTORC1 not addressed
7. 2022 Medium

   Showed RNF167 ubiquitinates GTP-bound, membrane-anchored Rab7 to sustain Rab7 membrane localization and regulate endosomal vesicle size, with disease variants impairing the reaction.

   Evidence Co-IP, in vitro ubiquitination, subcellular fractionation, microscopy, CMT2B variant analysis

   PMID:35887194

   Open questions at the time

   • Ubiquitination site and chain linkage on Rab7 not defined
   • Mechanistic link to Charcot-Marie-Tooth pathology not established
8. 2023 Medium

   Placed RNF167 in inflammatory signaling control by showing K33-linked ubiquitination of Tollip at K235 is required for suppression of TNF-α-induced NF-κB and MAPK activation.

   Evidence Reciprocal Co-IP via Tollip CUE domain, K33 linkage determination, K235R mutagenesis, TNF-α-stimulated signaling readouts

   PMID:37410058

   Open questions at the time

   • Downstream effector engaged by K33-ubiquitinated Tollip unclear
   • Physiological setting in vivo not tested
9. 2025 High

   Defined a dual-pathway mechanism by which RNF167 dampens antiviral interferon signaling, routing RIG-I/MDA5 to autophagy via K6/p62 and to the proteasome via K11.

   Evidence Linkage-specific ubiquitination assays, domain-level site mapping, p62 interaction studies, autophagy/proteasome inhibition, IFN-I readouts

   PMID:39994288

   Open questions at the time

   • Trigger determining K6 versus K11 chain choice unknown
   • Whether localization at endolysosomes is required for RLR targeting untested
10. 2025 Low

    Proposed that RNF167 heterodimerizes with RNF13 to co-regulate IDS maturation and the lysosomal trafficking of both ligases, extending RNF167 function into partner-modulated activity.

    Evidence Co-IP, AlphaFold3-guided prediction, glycosylation/maturation assays, localization analysis (preprint)

    PMID:bio_10.1101_2025.06.20.660705

    Open questions at the time

    • Heterodimer identified by Co-IP without reconstitution of the complex
    • Catalytic consequence of heterodimerization not directly demonstrated
    • Whether IDS is a direct substrate unresolved
11. 2025 Low

    Implicated SMAD3 as an upstream regulator that stabilizes Sestrin2 by tuning the RNF167/STAMBPL1 ubiquitination balance in gastric cancer.

    Evidence Co-IP, Western blot, immunofluorescence, SMAD3 gain/loss-of-function in gastric cancer cells

    PMID:40751214

    Open questions at the time

    • Interaction shown by Co-IP only without ubiquitination reconstitution for the SMAD3 axis
    • Whether SMAD3 acts on RNF167 catalysis or substrate access unclear

• How RNF167 selects among its diverse substrates and assembles distinct chain linkages (K6, K11, K29, K33) in different subcellular and signaling contexts remains unresolved.
• No structural model of substrate or E2 engagement
• Determinants of linkage-type specificity unknown
• Spatial coupling between localization and substrate choice undefined