CUEDC1

CUEDC1 is a CUE-domain-containing adaptor protein that acts as a negative regulator of oncogenic signaling cascades by promoting the proteasomal degradation of pathway components, while also being embedded in transcriptional circuits that drive cancer cell growth (PMID:33099540, PMID:41917169, PMID:41315933). Its expression is transcriptionally controlled in breast cancer by ERα through a CRISPR-validated intronic enhancer (CUTE), and the CUE domain is functionally required for CUEDC1 to rescue ERα-driven proliferation (PMID:30145202). As a degradation-promoting adaptor, CUEDC1 binds the E3 ligase Smurf2 and promotes its turnover, thereby stabilizing TβRI and suppressing TβRI/Smad signaling and EMT in non-small cell lung cancer (PMID:33099540); in a parallel mechanism, it binds STAT3 and drives its ubiquitination and proteasomal degradation to suppress JAK1/STAT3 signaling and reduce proliferation, migration, and invasion in esophageal cancer (PMID:41917169). In ER-positive breast cancer, CUEDC1 is transcriptionally upregulated by direct MAZ binding to its promoter and in turn modulates CACNG4 to activate PI3K/AKT signaling and enhance GLUT1-dependent glycolysis (PMID:41315933). Across these contexts CUEDC1 exerts both growth-promoting (PI3K/AKT-glycolysis, proliferation) and growth-suppressive (Smurf2/TβRI, STAT3) outputs depending on the partner engaged, with no unifying structural or enzymatic mechanism for partner selection characterized in the available corpus.

1. 2018 Medium

   Established the upstream transcriptional control of CUEDC1 and demonstrated that its CUE domain is functionally required, moving CUEDC1 from an uncharacterized gene to an ERα-driven effector of breast cancer proliferation.

   Evidence CRISPR-Cas9 functional enhancer screen plus ectopic expression with CUE-domain mutant rescue in breast cancer cells

   PMID:30145202

   Open questions at the time

   • No molecular partner of the CUE domain identified
   • Mechanism by which the CUE domain drives proliferation not defined
2. 2018 Low

   Showed CUEDC1 overexpression promotes proliferation in a non-breast lineage, hinting at broader pro-growth activity but without mechanistic placement.

   Evidence Lentiviral overexpression with CCK-8 and colony formation assays in MOLT-4 leukemic cells

   PMID:30295235

   Open questions at the time

   • Overexpression-only with no pathway placement
   • No binding partner or loss-of-function validation
3. 2020 Medium

   Provided the first physical-partner mechanism: CUEDC1 acts as a degradation-promoting adaptor that destabilizes Smurf2 to stabilize TβRI and suppress TβRI/Smad-driven EMT.

   Evidence Co-IP, siRNA/overexpression epistasis, migration/invasion assays, and xenografts in NSCLC cells

   PMID:33099540

   Open questions at the time

   • Single Co-IP without reciprocal validation of the CUEDC1–Smurf2 interaction
   • Whether CUE domain mediates Smurf2 binding not tested
   • Mechanism by which CUEDC1 promotes Smurf2 degradation unresolved
4. 2025 Medium

   Extended the degradation-adaptor model to a second cascade by showing CUEDC1 binds STAT3 and drives its ubiquitination and proteasomal turnover, suppressing JAK1/STAT3 signaling.

   Evidence Co-IP, ubiquitination assay, proteasome inhibitor rescue, and gain/loss-of-function phenotyping in esophageal cancer cells

   PMID:41917169

   Open questions at the time

   • No identified E3 ligase recruited to STAT3
   • Not independently replicated
   • Relationship to the Smurf2/TβRI mechanism unclear
5. 2025 Medium

   Defined a transcriptional-to-metabolic axis in which MAZ directly activates CUEDC1, which then modulates CACNG4 to engage PI3K/AKT and glycolysis, contrasting with CUEDC1's growth-suppressive roles elsewhere.

   Evidence ChIP, dual-luciferase reporter, RNA-seq, glycolysis assays, knockdown, and xenografts in ER-positive breast cancer

   PMID:41315933

   Open questions at the time

   • How CUEDC1 modulates CACNG4 (direct vs indirect) not established
   • Reconciliation of pro-growth vs tumor-suppressive outputs unresolved
6. 2025 Low

   Implicated CUEDC1 upstream of TGF-β/Smad in liver cancer EMT, consistent with but mechanistically thinner than the NSCLC Smurf2 model.

   Evidence siRNA knockdown with Western blot and Transwell assays in hepatocellular carcinoma cells

   PMID:39951906

   Open questions at the time

   • Single-method knockdown with no binding partner identified
   • No biochemical reconstitution of pathway placement
7. 2025 Low

   Identified an in vivo physiological role for Cuedc1 in an adrenal blood-pressure/aldosterone pathway, broadening its biology beyond cancer.

   Evidence Congenic knock-in QTL genetics with in vivo blood pressure and aldosterone measurements in rats

   PMID:40332416

   Open questions at the time

   • No molecular mechanism for CUEDC1's action in the adrenal pathway
   • Causal gene resolution within the QTL incomplete

• It remains unknown what unifying biochemical mechanism (CUE-domain ligand, structural basis of partner selection) explains how CUEDC1 alternately suppresses Smurf2/STAT3 and promotes PI3K/AKT signaling across tissues.
• No structural model of CUEDC1 or its CUE domain
• No identified direct CUE-domain ligand
• Determinants of context-dependent pro- vs anti-growth output unknown