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Showing UBE2E2UBCH8 is a alias.

UBE2E2

Ubiquitin-conjugating enzyme E2 E2 · UniProt Q96LR5

Length
201 aa
Mass
22.3 kDa
Annotated
2026-06-10
13 papers in source corpus 5 papers cited in narrative 5 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

UBE2E2 is a functional ubiquitin-conjugating (E2) enzyme that forms an E1-dependent thioester bond with ubiquitin and operates within the ubiquitin-proteasome system to regulate cell proliferation and protein stability (PMID:9371400). It elongates polyubiquitin chains in cooperation with the Nedd4 E3 ligase, and its active-site Cys139 is required both for catalytic function and for proper subcellular distribution (PMID:38064504, PMID:36765041). In ovarian cancer cells, UBE2E2 binds Nrf2 directly through its N-terminal region (residues 1–52), promotes p62 accumulation and Nrf2-ARE antioxidant signaling, and stabilizes the EMT driver Snail by protecting it from ubiquitin-mediated degradation, thereby promoting migration and metastasis (PMID:36765041). In pancreatic β-cells, UBE2E2 overexpression suppresses proliferation in association with elevated p21 and reduces β-cell mass, producing glucose intolerance without directly impairing glucose-stimulated insulin secretion (PMID:38064504). Genetic dissection of the T2D-associated locus indicates that noncoding regulatory variants co-regulate UBE2E2 with the neighboring UBE2E1, and combined loss of both genes in mice recapitulates metabolic phenotypes more completely than loss of either alone (PMID:39656538).

Mechanistic history

Synthesis pass · year-by-year structured walk · 5 steps
  1. 1997 High

    Established that UBE2E2 is a genuine catalytic E2 enzyme rather than an inert homolog, defining its biochemical identity within the ubiquitin system.

    Evidence In vitro E1-dependent thioester ubiquitin-loading assay with cDNA cloning, sequence analysis, and FISH mapping to 3p24.2

    PMID:9371400

    Open questions at the time
    • No cognate E3 ligases or substrates identified at this stage
    • Chain-type specificity not determined
    • No cellular or physiological role established
  2. 2017 Low

    Began linking UBE2E2 to substrate turnover by nominating phosphorylated c-MYC, KDM4A, and KMT5A as ubiquitination targets controlling proliferation and the DNA damage response.

    Evidence Immunohistochemistry of putative substrates with PCNA/γH2AX staining in a rat thioacetamide hepatocarcinogenesis model

    PMID:28899750

    Open questions at the time
    • No in vitro ubiquitination assay confirms these as direct UBE2E2 substrates
    • Correlative tissue immunostaining only, no biochemical reconstitution
    • Mechanism of substrate selection unknown
  3. 2023 Medium

    Defined a substrate-stabilizing role and a direct binding partner, showing UBE2E2 drives EMT via an Nrf2–p62–Snail axis and that catalytic Cys139 is essential.

    Evidence Reciprocal co-IP, N-terminal truncation mapping, Cys139 active-site mutagenesis, knockdown/overexpression with EMT readouts, and xenograft in ovarian cancer cells

    PMID:36765041

    Open questions at the time
    • Whether UBE2E2 ubiquitinates Snail or Nrf2 directly versus regulating their stability indirectly is not resolved
    • Single-lab study without independent replication
    • Chain linkage on Snail not characterized
  4. 2024 Medium

    Connected UBE2E2 enzymatic activity to a specific E3 partner and an in vivo metabolic phenotype, showing it elongates polyubiquitin chains with Nedd4 and restrains β-cell proliferation.

    Evidence Ubiquitination assay with proteomic chain-type analysis plus β-cell-specific transgenic mice with islet/GSIS assays and high-fat-diet challenge

    PMID:38064504

    Open questions at the time
    • Direct substrates ubiquitinated via the UBE2E2–Nedd4 pair not identified
    • Mechanistic link from chain elongation to p21 induction unresolved
    • Single overexpression model; loss-of-function consequences not assessed here
  5. 2024 Medium

    Addressed which gene at the T2D locus is causal, finding polygenic regulatory effects implicating UBE2E2 together with UBE2E1 rather than UBE2E2 alone.

    Evidence CRISPR excision and CRISPRi of noncoding regions, compound heterozygous mouse knockouts, ex vivo adipogenesis, and diet-induced obesity

    PMID:39656538

    Open questions at the time
    • Cannot cleanly isolate UBE2E2-specific contribution from UBE2E1 and other locus genes
    • Molecular target of the regulatory variants not pinpointed
    • Tissue of primary effect not definitively established

Open questions

Synthesis pass · forward-looking unresolved questions
  • The direct, biochemically validated substrate repertoire of UBE2E2 and the chain linkages it builds with specific E3 ligases remain undefined.
  • No reconstituted E2-E3-substrate ubiquitination defining direct targets
  • Structural basis of E3 partnering and Cys139-dependent localization unknown
  • Reconciliation of growth-suppressive (β-cell) versus oncogenic (ovarian) roles not mechanistically explained

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0140096 catalytic activity, acting on a protein 3 GO:0016740 transferase activity 2
Pathway
R-HSA-392499 Metabolism of proteins 3

Evidence

Reading pass · 5 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
1997 UBE2E2 protein forms a thioester bond with ubiquitin in an E1-dependent manner, confirming it is a functional ubiquitin-conjugating E2 enzyme. Its UBC domain shares >90% identity with human UbcH6, mouse UbcM2, and Drosophila UbcD2, and the gene was mapped to chromosome 3p24.2. In vitro thioester bond formation assay (E1-dependent ubiquitin loading), cDNA cloning, amino acid sequence analysis, fluorescence in situ hybridization (FISH) Cytogenetics and cell genetics High 9371400
2023 UBE2E2 interacts directly with Nrf2 via its N-terminal region (residues 1–52), promotes p62 accumulation and Nrf2-ARE antioxidant signaling, and stabilizes Snail protein by inhibiting its ubiquitin-mediated degradation, thereby driving EMT in ovarian cancer cells. Mutation of the active-site cysteine (Cys139) impaired both UBE2E2 function and its cellular distribution. Co-immunoprecipitation (co-IP), immunofluorescence, N-terminal deletion/truncation mapping, active-site cysteine mutagenesis (Cys139), siRNA knockdown and overexpression with migration/EMT readouts, xenograft mouse model Cell death & disease Medium 36765041
2024 UBE2E2 mediates elongation of polyubiquitin chains in cooperation with the Nedd4 E3 ubiquitin ligase, as shown by ubiquitination assays in pancreatic β-cell-specific transgenic mice. Overexpression of UBE2E2 suppressed β-cell proliferation (associated with elevated p21 expression) and reduced β-cell mass, leading to glucose intolerance, without directly impairing glucose-stimulated insulin secretion from isolated islets. Ubiquitination assay, proteomic analysis of polyubiquitin chain types, pancreatic β-cell-specific transgenic mouse model, islet isolation/glucose-stimulated insulin secretion assay, gene expression analysis (p21), high-fat diet challenge Diabetes Medium 38064504
2017 In rat liver cells, downregulation of UBE2E2 leads to accumulation of its ubiquitination target proteins phosphorylated c-MYC, KDM4A, and KMT5A (but not p21WAF1/CIP1), resulting in increased cell proliferation (PCNA+) and slowed DNA damage response (γH2AX+) in GST-P+ preneoplastic foci. Immunohistochemistry for ubiquitination target proteins (p-c-MYC, KDM4A, KMT5A, p21), PCNA and γH2AX staining, rat hepatocarcinogenesis model with thioacetamide treatment Toxicology and applied pharmacology Low 28899750
2024 CRISPR excision of noncoding SNV-containing regions near UBE2E2 and CRISPRi screening across the locus suggest that T2D-associated noncoding variants concomitantly regulate UBE2E2, the neighboring UBE2E1, and other locus genes; compound heterozygous loss of both Ube2e2 and Ube2e1 in mice better replicated pathological adiposity and metabolic phenotypes than loss of either gene alone, implicating polygenic regulatory effects. CRISPR excision of noncoding regions, CRISPRi regulatory screen, compound heterozygous mouse knockouts, ex vivo adipogenesis assays, diet-induced obesity model JCI insight Medium 39656538

Source papers

Stage 0 corpus · 13 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2010 A genome-wide association study in the Japanese population identifies susceptibility loci for type 2 diabetes at UBE2E2 and C2CD4A-C2CD4B. Nature genetics 211 20818381
2018 Impact of KCNQ1, CDKN2A/2B, CDKAL1, HHEX, MTNR1B, SLC30A8, TCF7L2, and UBE2E2 on risk of developing type 2 diabetes in Thai population. BMC medical genetics 27 29871606
1997 cDNA cloning, characterization, and chromosome mapping of UBE2E2 encoding a human ubiquitin-conjugating E2 enzyme. Cytogenetics and cell genetics 15 9371400
2016 Type 2 Diabetes Risk Allele UBE2E2 Is Associated With Decreased Glucose-Stimulated Insulin Release in Elderly Chinese Han Individuals. Medicine 12 27175665
2023 UBE2E2 enhances Snail-mediated epithelial-mesenchymal transition and Nrf2-mediated antioxidant activity in ovarian cancer. Cell death & disease 10 36765041
2016 Identification of epigenetically downregulated Tmem70 and Ube2e2 in rat liver after 28-day treatment with hepatocarcinogenic thioacetamide showing gene product downregulation in hepatocellular preneoplastic and neoplastic lesions produced by tumor promotion. Toxicology letters 10 27914986
2013 Putative association between UBE2E2 polymorphisms and the risk of gestational diabetes mellitus. Gynecological endocrinology : the official journal of the International Society of Gynecological Endocrinology 9 23862583
2015 Association between UBE2E2 variant rs7612463 and type 2 diabetes mellitus in a Chinese Han population. Acta biochimica Polonica 8 26020062
2014 Lack of association between UBE2E2 gene polymorphism (rs7612463) and type 2 diabetes mellitus in a Saudi population. Acta biochimica Polonica 5 25337779
2024 Overexpression of UBE2E2 in Mouse Pancreatic β-Cells Leads to Glucose Intolerance via Reduction of β-Cell Mass. Diabetes 4 38064504
2022 PPARG, TMEM163, UBE2E2, and WFS1 Gene Polymorphisms Are Not Significant Risk Factors for Gestational Diabetes in the Polish Population. Journal of personalized medicine 4 35207731
2024 Noncoding variation near UBE2E2 orchestrates cardiometabolic pathophenotypes through polygenic effectors. JCI insight 3 39656538
2017 Downregulation of UBE2E2 in rat liver cells after hepatocarcinogen treatment facilitates cell proliferation and slowing down of DNA damage response in GST-P-expressing preneoplastic lesions. Toxicology and applied pharmacology 2 28899750

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