ABTB2 is a large ankyrin-repeat and BTB/POZ-domain protein with protein-protein interaction domains and isoform diversity. Direct experimental work in pancreatic ductal adenocarcinoma models supports a substrate-adaptor-like role in which ABTB2 binds TRAP1, promotes TRAP1 ubiquitination-dependent degradation, and suppresses Wnt/beta-catenin and PI3K/Akt signaling. ABTB2 has been detected in the nucleoplasm, but its normal tissue substrates and broader physiological roles remain incompletely defined.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0046982 protein heterodimerization activity | IEA GO_REF:0000002 | MARK AS OVER ANNOTATED | Summary: This InterPro-derived annotation is consistent with ABTB2 containing protein-interaction domains, including histone-fold-like, ankyrin-repeat, and BTB/POZ features, but it is too broad to describe ABTB2's best-supported molecular function. Reason: Retain the domain context but do not treat generic heterodimerization as a core function. The direct ABTB2 literature supports a more informative substrate-adaptor-like role in TRAP1 ubiquitination-dependent degradation, captured below as GO:1990756. Supporting Evidence: UniProt:Q8N961 DR InterPro; IPR009072; Histone-fold. PMID:41322190 ABTB2 interacts with tumour necrosis factor receptor-associated protein 1 (TRAP1), promoting its ubiquitin-dependent degradation |
| GO:0005515 protein binding | IPI PMID:36931259 A central chaperone-like role for 14-3-3 proteins in human c... | MARK AS OVER ANNOTATED | Summary: The IPI annotation records a 14-3-3 epsilon/YWHAE interaction detected in a broad 14-3-3 interactome study. This supports an ABTB2 protein interaction but not a specific molecular activity. Reason: GO:0005515 is intentionally generic and is not useful as a retained core molecular-function annotation. ABTB2's direct, more informative function is better represented as ubiquitin-like ligase-substrate adaptor activity. Supporting Evidence: UniProt:Q8N961 CC Q8N961; P62258: YWHAE; NbExp=2; IntAct=EBI-11603395, EBI-356498; PMID:36931259 Here, we map the interactomes of all human 14-3-3 paralogs |
| GO:0005654 nucleoplasm | IDA GO_REF:0000052 | KEEP AS NON CORE | Summary: HPA immunofluorescence supports nucleoplasm localization. Direct ABTB2 functional work also links the protein to intracellular protein-complex contexts, but localization is not itself the core proteostasis function. Reason: Keep as a supported localization/context annotation. It should not be used to infer a nuclear-specific core function, since the strongest mechanistic evidence concerns ABTB2-dependent TRAP1 ubiquitination and degradation in cancer models. |
| GO:1990756 ubiquitin-like ligase-substrate adaptor activity | IDA PMID:41322190 Mechanistic and functional characterization of ABTB2 as a no... | NEW | Summary: Lyu et al. identify TRAP1 as an ABTB2-interacting protein and show that ABTB2 overexpression increases TRAP1 ubiquitination and promotes TRAP1 degradation. The same study reports ABTB2 interaction with cullin-3, making the PN-projected Cul3 substrate-receptor context supportable for ABTB2. Reason: This is the most informative molecular-function term for the direct ABTB2 evidence. It captures ABTB2's substrate-adaptor-like role in bringing a ubiquitin-ligase system to a substrate, while avoiding a catalytic E3-ligase annotation. The older BPOZ-2/TdT and BPOZ-2/eEF1A1 literature was not used as primary ABTB2 evidence because that nomenclature overlaps with ABTB1; the 2025 ABTB2/TRAP1 study provides direct gene-specific support. Supporting Evidence: PMID:41322190 Co-immunoprecipitation using Abs specific to ABTB2 and TRAP1, followed by western blotting, confirmed the specific interaction between ABTB2 and TRAP1 PMID:41322190 multiple mono-ubiquitinated TRAP1 (Figures 8F and S10) in ABTB2-OE cells, suggesting that ABTB2-induced protein ubiquitination contributes to TRAP1 degradation PMID:41322190 We also found that ABTB2 interacts with cullin-3 (Figure S9) file:human/ABTB2/ABTB2-deep-research-manual.md Direct ABTB2 evidence supports a substrate-adaptor-like role for TRAP1 ubiquitination-dependent degradation. |
| GO:0016567 protein ubiquitination | IDA PMID:41322190 Mechanistic and functional characterization of ABTB2 as a no... | NEW | Summary: ABTB2 overexpression increases pan-protein ubiquitination and TRAP1 ubiquitination, with TRAP1 degradation downstream of the ABTB2-TRAP1 interaction. Reason: Add as a biological-process companion to the molecular-function adaptor annotation. The evidence supports ABTB2 involvement in TRAP1 protein ubiquitination, while the molecular-function annotation should remain adaptor activity rather than catalytic ubiquitin ligase activity. Supporting Evidence: PMID:41322190 Using western blotting, we detected abundant ubiquitination of whole proteins (Figure 8E) and multiple mono-ubiquitinated TRAP1 (Figures 8F and S10) in ABTB2-OE cells PMID:41322190 ABTB2 promotes TRAP1 degradation via ubiquitination (Figure 8) file:human/ABTB2/ABTB2-deep-research-manual.md Add `GO:0016567 protein ubiquitination` as a new biological-process companion annotation |
Loading supporting content…
Download this section (compressed HTML)Q: Does endogenous ABTB2 form a native CRL3 complex with CUL3 in non-cancer tissues, and is TRAP1 a physiological substrate outside pancreatic cancer models?
Q: What additional ABTB2 substrates explain its tissue-specific and disease-context effects?
Experiment: Test endogenous ABTB2-CUL3-TRAP1 complex formation with reciprocal co-IP, proximity ligation, and BTB-domain mutant rescue in cells with native ABTB2 expression.
Hypothesis: ABTB2 uses its BTB/POZ domain to recruit CUL3 while its substrate-recognition regions engage TRAP1.
Type: co-immunoprecipitation and mutant rescue
Experiment: Measure TRAP1 ubiquitination and stability after ABTB2 loss or rescue with CUL3 depletion, proteasome inhibition, and ubiquitin-linkage/site mapping.
Hypothesis: ABTB2-dependent TRAP1 degradation requires a CUL3 ubiquitin-ligase complex.
Type: ubiquitination and protein-turnover assay
Loading supporting content…
Download this section (compressed HTML)Loading supporting content…
Download this section (compressed HTML)Loading supporting content…
Download this section (compressed HTML)Loading supporting content…
Download this section (compressed HTML)