ARRDC4

ARRDC4 is an α-arrestin scaffold protein that couples nutrient transporter trafficking, extracellular vesicle biogenesis, and innate immune signaling (PMID:35950500, PMID:34188787, PMID:28594402). Through specific residues in its C-terminal arrestin-fold domain, ARRDC4 binds the glucose transporter GLUT1 and drives its endocytosis and lysosomal trafficking, thereby restricting cellular glucose uptake; in cardiomyocytes this promotes glucose-deprivation ER stress and cell death during ischemia, and its loss augments myocardial glucose uptake, glycogen storage, and mitochondrial respiration to protect against infarction and hyperglycemic injury (PMID:35950500, PMID:38946541). This glucose-restricting axis is wired into a feedback loop in which high glucose drives MondoA-dependent transcriptional upregulation of ARRDC4 (PMID:38946541). ARRDC4 is also required for extracellular vesicle biogenesis: K29-linked polyubiquitination at Lys270 by the E3 ligase Nedd4-2 enables EV release and the packaging of cargo such as the metal transporter DMT1, and in epididymal epithelium ARRDC4-dependent EVs confer functional competence on sperm (PMID:35106941, PMID:34188787). In innate immunity, ARRDC4 acts as a scaffold that recruits TRIM65 to K63-ubiquitinate MDA5 and activate proinflammatory signaling during enterovirus infection, and during influenza A infection it senses the viral PA protein and engages PFKM to potentiate an FBP–HSP90β–IKK antiviral axis (PMID:28594402, PMID:40875808). m6A methylation of ARRDC4 mRNA by METTL14, read by YTHDF2, governs its transcript stability and its tumor-suppressive output in colorectal cancer (PMID:34916487).

1. 2017 Medium

   Established that ARRDC4 functions as a signaling scaffold in innate immunity, linking it for the first time to antiviral cytokine responses rather than only trafficking.

   Evidence Reciprocal Co-IP, N-domain deletion mapping, and ubiquitination assays in THP-1-derived macrophages during EV71 infection

   PMID:28594402

   Open questions at the time

   • Not independently replicated
   • Whether MDA5 engagement is constitutive or infection-induced not resolved
   • No structural basis for the N-domain/MDA5/TRIM65 ternary assembly
2. 2021 Medium

   Defined how ARRDC4 levels are post-transcriptionally controlled, showing m6A methylation tunes its abundance and downstream tumor-suppressive activity.

   Evidence m6A profiling, siRNA knockdown, mRNA stability assays, and YTHDF2 Co-IP in colorectal cancer

   PMID:34916487

   Open questions at the time

   • Direct mechanism by which ARRDC4 protein suppresses ZEB1/metastasis not defined
   • Single lab
3. 2021 High

   Demonstrated ARRDC4 is genetically required for extracellular vesicle biogenesis in vivo and that these EVs deliver physiological function to recipient cells.

   Evidence Arrdc4 knockout mouse, EV quantification from epididymal epithelium, sperm functional assays, and rescue by wild-type EV supplementation

   PMID:34188787

   Open questions at the time

   • Molecular machinery ARRDC4 uses to drive EV formation not resolved
   • Generalizability beyond epididymal epithelium unknown
4. 2022 High

   Mapped the GLUT1-binding determinants in the C-terminal arrestin fold and established ARRDC4 as a driver of GLUT1 endocytosis that controls cardiomyocyte glucose supply and ischemic survival.

   Evidence Co-IP, scanning mutagenesis with AI structure-function analysis, glucose uptake and ER stress assays, and KO mouse myocardial infarction model

   PMID:35950500

   Open questions at the time

   • Whether GLUT1 is ubiquitinated/adapted to endocytic machinery by ARRDC4 not shown
   • Selectivity for GLUT1 over other transporters not established
5. 2022 High

   Identified the post-translational switch for ARRDC4-dependent EV biogenesis, pinning EV release and cargo packaging to Nedd4-2-mediated K29 ubiquitination at Lys270.

   Evidence Mass spectrometry of ubiquitinated lysines, K270R mutagenesis, EV quantification, DMT1 activity assays, and Nedd4-2 co-expression

   PMID:35106941

   Open questions at the time

   • How K29-linked chains mechanistically promote EV budding unknown
   • Range of cargoes selected by this modification beyond DMT1 not defined
6. 2024 High

   Closed a regulatory loop showing glucose itself induces ARRDC4 via MondoA, and extended the GLUT1-trafficking mechanism to whole-body glucose handling and hyperglycemic tissue protection.

   Evidence Cardiomyocyte and T2D patient-derived muscle cells, Arrdc4 KO and cardiac AAV overexpression mice, hemodynamics, treadmill testing, and GLUT1 trafficking assays

   PMID:38946541

   Open questions at the time

   • Direct MondoA binding to the ARRDC4 locus not detailed
   • Tissue-specific contributions to systemic phenotype not dissected
7. 2025 Medium

   Revealed a metabolic route by which ARRDC4 amplifies antiviral immunity, sensing influenza PA and rewiring PFKM-driven glycolytic flux to stabilize HSP90β and activate IKK-dependent signaling.

   Evidence Co-IP for ARRDC4–PA and ARRDC4–PFKM (His298), PFKM enzymatic assays, HSP90β ubiquitination assays, and in vitro/in vivo FBP supplementation

   PMID:40875808

   Open questions at the time

   • Single lab, not independently replicated
   • Relationship of this axis to the earlier MDA5/TRIM65 mechanism unresolved
   • Structural basis of PFKM His298 engagement not shown
8. 2026 Medium

   Extended ARRDC4 function to mitochondrial lipid reprogramming and a paracrine exosome circuit, showing it packages and exports WWP1 to restrain EMT in neighboring cancer cells.

   Evidence Exosome Co-IP for ARRDC4–WWP1, mitochondrial fractionation, exosome quantification, uptake assays, and EMT marker analysis in colorectal cancer-initiating cells

   PMID:42163297

   Open questions at the time

   • How an arrestin scaffold reaches the mitochondrial matrix unexplained
   • Mechanism linking mitochondrial localization to exosome cargo selection unknown
   • Single lab
9. 2025 Low

   Linked ARRDC4-controlled glucose uptake to gasdermin E-dependent pyroptosis as a determinant of circulating tumor cell aggressiveness.

   Evidence In vivo CTC selection, Arrdc4 knockdown/overexpression in xenograft and syngeneic models, glucose uptake assays, and immunocompetent vs immunocompromised comparison (preprint)

   PMID:bio_10.1101_2025.01.26.634904

   Open questions at the time

   • Preprint, abstract-level mechanism
   • Gasdermin E link inferred without reconstitution
   • Causal chain from glucose uptake to pyroptosis not established

• How ARRDC4's distinct activities — GLUT1 endocytosis, ubiquitin-dependent EV/exosome biogenesis, immune scaffolding, and mitochondrial lipid reprogramming — are coordinated within one protein remains unresolved.
• No unifying structural model relating the N-domain and arrestin-fold functions
• Determinants of subcellular targeting (plasma membrane vs mitochondria vs EVs) unknown
• Tissue/context selection among the multiple mechanisms not defined