RNF185

RNF185 is a RING-domain E3 ubiquitin ligase anchored at the ER and mitochondrial outer membranes that selects diverse substrates and writes distinct ubiquitin linkages to route them toward proteasomal degradation, selective autophagy, or signaling activation (PMID:21931693, PMID:24019521, PMID:28273161). At the ER it forms a membrane-embedded ERAD module with TMUB1/2 and Membralin (TMEM259) that cooperates with the cytosolic ligase UBE3C and the p97 ATPase to degrade misfolded or unassembled membrane proteins, including CFTR and CFTRΔF508, unassembled Tapasin, and viral envelope glycoproteins, thereby controlling protein quality control and indirectly setting MHC-I surface levels (PMID:24019521, PMID:32738194, PMID:39353943). Through K27- and K63-linked chains it functions as a positive regulator of innate immunity and selective autophagy: it ubiquitinates cGAS (K27) to enhance its enzymatic activity and IRF3-dependent gene expression (PMID:28273161), and modifies mitochondrial substrates BNIP1 (K63) and TUFM (K27) to recruit the autophagy receptor p62/SQSTM1 and drive LC3-dependent mitophagy (PMID:21931693, PMID:38084826). RNF185 also degrades a range of cytoplasmic and signaling substrates — Dvl2 to restrain Wnt/β-catenin signaling (PMID:24727453), JWA to promote gastric cancer cell migration (PMID:29481911), IDH2 to limit NADPH production (PMID:38167476), and BAK1 to maintain mitochondrial integrity and restrain cGAS-STING-driven apoptosis (PMID:41254727). Upon DNA damage it undergoes ATM/ATR-dependent phosphorylation, NUP88-mediated nuclear translocation, and sequential switching of RPA1 ubiquitin linkages (K6/K63 then K48), coordinating replication fork restart and homologous recombination in competition with the deubiquitinase OTUB1 (PMID:41997286).

1. 2011 Medium

   Established RNF185 as a mitochondrial outer-membrane E3 ligase that links substrate ubiquitination to selective autophagy, answering where the enzyme acts and how it engages the autophagy machinery.

   Evidence Subcellular fractionation, imaging, Co-IP and in vivo ubiquitination assays showing K63-linked ubiquitination of BNIP1 and p62 recruitment

   PMID:21931693

   Open questions at the time

   • Single lab; physiological trigger for mitophagy not defined
   • Whether BNIP1 is the principal mitophagy substrate not established
2. 2013 High

   Defined RNF185 as a core ERAD ligase by showing it controls CFTR turnover in a RING- and proteasome-dependent manner together with RNF5, establishing its protein quality-control role.

   Evidence siRNA knockdown, pulse-chase turnover, proteasome inhibition, RING mutant, epistasis with RNF5 in two CFTR substrates

   PMID:24019521

   Open questions at the time

   • Mechanism of misfolded-substrate recognition not resolved
   • Ubiquitin linkage type on CFTR not specified
3. 2014 Medium

   Extended RNF185 substrate range to cytoplasmic signaling by showing it degrades Dvl2 to suppress Wnt/β-catenin output and osteogenic differentiation.

   Evidence Co-IP, ubiquitination assay, gain/loss-of-function with ALP and qRT-PCR readouts, Dvl2 rescue

   PMID:24727453

   Open questions at the time

   • Ubiquitin linkage on Dvl2 not defined
   • Single lab; in vivo relevance untested
4. 2017 High

   Showed RNF185 can be an activating rather than degradative ligase, using K27-linked ubiquitination of cGAS to potentiate innate antiviral signaling.

   Evidence Reciprocal Co-IP, linkage-specific ubiquitination, gain/loss-of-function reporter assays during HSV-1 infection

   PMID:28273161

   Open questions at the time

   • CGAS ubiquitination site not mapped
   • Structural basis for non-degradative K27 chains unknown
5. 2018 Medium

   Identified site-specific (K158) ubiquitination of JWA by RNF185 as a pro-metastatic axis in gastric cancer, linking the ligase to tumor cell migration.

   Evidence Co-IP, site-specific mutagenesis, migration/in vivo metastasis assays, rescue

   PMID:29481911

   Open questions at the time

   • Single lab; broader substrate context unclear
   • Regulation of RNF185 in tumors not defined
6. 2020 High

   Resolved the molecular architecture of RNF185-dependent ERAD by defining the RNF185/Membralin/TMUB1/2 complex acting with UBE3C and p97 on a specific subset of misfolded membrane proteins.

   Evidence Genome-wide CRISPR screen, biochemical fractionation, mass spectrometry, Co-IP

   PMID:32738194

   Open questions at the time

   • Substrate selectivity determinants within the complex not fully defined
   • Stoichiometry of the membrane complex not resolved
7. 2022 High

   Demonstrated RNF185 can route a substrate to autophagy rather than the proteasome, K27-ubiquitinating Ebolavirus GP1,2 at K673 for p62/ATG-dependent lysosomal degradation.

   Evidence Co-IP, site-directed mutagenesis (K673), ATG3/ATG5 knockouts, autophagy flux assays, linkage-specific ubiquitination

   PMID:36224200

   Open questions at the time

   • What dictates lysosomal vs proteasomal fate of K27-modified substrates unknown
8. 2023 Medium

   Implicated RNF185 in restricting SARS-CoV-2 by regulating envelope protein stability at the ER, expanding its antiviral role.

   Evidence Genetic screen, co-localization imaging, siRNA knockdown with viral titer readout

   PMID:37095859

   Open questions at the time

   • Direct ubiquitination of E protein not demonstrated
   • Linkage type and degradation route unspecified
9. 2024 High

   Connected RNF185-dependent ERAD to immune presentation by showing the RNF185/Membralin complex degrades unassembled Tapasin and thereby limits MHC-I surface expression.

   Evidence Unbiased proteomics, CRISPR knockout, Co-IP, flow cytometry for surface MHC-I, degradation assays

   PMID:39353943

   Open questions at the time

   • Whether Tapasin degradation is the dominant determinant of MHC-I changes in vivo not established
10. 2024 Medium

    Established TUFM as a mitochondrial RNF185 substrate, with K27-linked ubiquitination via transmembrane domain 1 enabling p62-driven mitophagy during Senecavirus A infection.

    Evidence Co-IP, GST pulldown, linkage- and site-specific ubiquitination, domain deletion analysis

    PMID:38084826

    Open questions at the time

    • Generality of TUFM mitophagy beyond viral infection unclear
    • Single lab
11. 2024 Medium

    Linked RNF185 to metabolic control, showing D-mannose-induced RNF185 degrades IDH2 to suppress NADPH production in breast cancer cells.

    Evidence RNA-seq, Co-IP, ubiquitination and NADPH assays, colony formation/CCK-8 readouts

    PMID:38167476

    Open questions at the time

    • Mechanism of D-mannose-driven RNF185 upregulation not defined
    • Ubiquitin linkage on IDH2 unspecified
12. 2024 Medium

    Defined a metastasis-suppressive RNF185 pathway in prostate cancer acting upstream of COL3A1.

    Evidence shRNA knockdown, RNA-seq, migration/invasion assays, xenograft model, COL3A1 co-inhibition rescue

    PMID:37831068

    Open questions at the time

    • Whether COL3A1 regulation is direct or transcriptional not resolved
    • No direct ubiquitination substrate identified in this axis
13. 2025 Medium

    Showed RNF185 ubiquitinates BAK1 to preserve mitochondrial integrity, with its loss triggering mtDNA release and cGAS-STING-IRF3-driven apoptosis in ESCC.

    Evidence CRISPR knockout, IP, ubiquitination assay, luciferase reporter, ChIP-qPCR, electron microscopy, xenograft

    PMID:41254727

    Open questions at the time

    • BAK1 ubiquitination site and linkage not defined
    • Relationship to RNF185's cGAS-activating role not reconciled
14. 2026 Medium

    Revealed a damage-induced nuclear function in which phosphorylated RNF185 sequentially switches RPA1 ubiquitin linkages to coordinate fork restart and homologous recombination.

    Evidence Co-IP, linkage- and site-specific ubiquitination (T106, K458), ATM/ATR inhibition, OTUB1 competition, HR and fork-restart assays, in vivo irradiation/cisplatin sensitivity

    PMID:41997286

    Open questions at the time

    • Single lab; nuclear translocation kinetics relative to membrane pool unclear
    • How the K6/K63-to-K48 switch is timed not mechanistically resolved

• How RNF185 selects among its many substrates and partitions between ER membrane, mitochondrial, and nuclear pools to specify proteasomal degradation, autophagy, or signaling activation remains unresolved.
• No unifying determinant of substrate or linkage choice identified
• Dynamic regulation of subcellular distribution not characterized
• No structural model of RNF185 substrate engagement