Mucosal DUOX1-DUOXA1 hydrogen peroxide generator and epithelial signaling module

Conserved vertebrate apical epithelial NADPH oxidase module in which the maturation factor DUOXA1 (maturation factor of dual oxidase 1) chaperones and assembles in a 1:1 heterodimeric complex with dual oxidase 1 (DUOX1) in the endoplasmic reticulum to target the holoenzyme to the apical plasma membrane of ciliated airway, urothelial, and squamous mucosal epithelia, where DUOX1 catalyzes Ca2+-activated, NADPH-dependent transmembrane electron transfer and extracellular hydrogen peroxide (H2O2) generation. Despite carrying an N-terminal extracellular peroxidase-homology domain (PHD), vertebrate DUOX1 lacks heme-binding histidines and does not possess intrinsic peroxidase activity. Instead, the extracellular H2O2 generated by the apical DUOX1-DUOXA1 complex feeds into two major downstream physiological pathways: (1) mucosal antimicrobial host defense, in which secreted lactoperoxidase (LPO) uses DUOX1-derived H2O2 to oxidize thiocyanate (SCN-) into hypothiocyanite (OSCN-) in the airway surface liquid, and (2) paracrine and autocrine epithelial redox signaling triggered by damage cues (extracellular ATP, Ca2+ influx, IL-33) that drive wound repair and mucin secretion.

MODULE:mucosal_duox1_lactoperoxidase_antimicrobial_systemDRAFTCONCRETEBiological Processmodules/mucosal_duox1_lactoperoxidase_antimicrobial_system.yaml
NAD(P)H oxidase H2O2-forming activityGO:0016174 hydrogen peroxide biosynthetic processGO:0050665 innate immune response in mucosaGO:0002227 wound healingGO:0042060
PMID:32929281
Structures of mouse DUOX1-DUOXA1 provide mechanistic insights into enzyme activation and regulation.
Cryo-EM structures of the mouse DUOX1-DUOXA1 complex reveal the 1:1 heterodimer and dimer-of-dimer assembly, Ca2+-regulated cytosolic EF-hand and dehydrogenase domains, two-heme transmembrane electron transfer path, and absence of heme in the extracellular PHD domain.
Here I report cryo-EM structures of mouse DUOX1–DUOXA1 complexes in NADPH-free, NADPH-bound and dimer-of-dimer states, providing structural mechanisms underlying DUOX1–DUOXA1 activation and regulation and molecular insights into ROS production.
PMID:33420071
Structures of human dual oxidase 1 complex in low-calcium and high-calcium states.
Co-expression of human DUOX1 and DUOXA1 forms an active plasma membrane complex that catalyzes Ca2+-activated, NADPH-dependent H2O2 production while lacking heme-coordinating histidines in the PHD.
we found the co-expression of DUOX1 and DUOXA1 resulted in cell membranes that showed robust calcium-activated, NADPH-dependent hydrogen peroxide production detected by the Amplex Red assay
PMID:19460756
Caenorhabditis elegans and human dual oxidase 1 (DUOX1) "peroxidase" domains: insights into heme binding and catalytic activity.
Biochemical characterization shows that the human DUOX1 ectodomain does not bind heme and has no intrinsic peroxidase activity.
the isolated hDUOX1(1-593) does not bind heme and has no intrinsic peroxidase activity
PMID:34168077
Dual oxidase 1 promotes antiviral innate immunity.
Demonstrates in Duox1-/- mice that Duox1 is required for airway mucosal antiviral innate immunity and viral clearance in vivo.
Here, we show that Duox1 promotes antiviral innate immunity in vivo. Upon influenza airway challenge, Duox1-/- mice have enhanced mortality, morbidity, and impaired lung viral clearance.
PMID:39126279
The NADPH oxidases DUOX1 and DUOX2 are sorted to the apical plasma membrane in epithelial cells via their respective maturation factors DUOXA1 and DUOXA2.
Demonstrates that DUOX1 is sorted to the apical plasma membrane in polarized epithelial cells specifically via its transmembrane maturation factor DUOXA1.
Here we show that DUOX1 and DUOX2 are correctly sorted to the apical membrane via the membrane-spanning DUOX maturation proteins DUOXA1 and DUOXA2, respectively, when co-expressed in MDCK epithelial cells.
file:genes/human/DUOX1/DUOX1-ai-review.yaml
Human DUOX1 gene review
Grounds human DUOX1 (UniProtKB:Q9NRD9) as a Ca2+-regulated apical epithelial H2O2-producing NADPH oxidase lacking intrinsic peroxidase activity.
file:genes/mouse/Duox1/Duox1-ai-review.yaml
Mouse Duox1 gene review
Grounds mouse Duox1 (UniProtKB:A2AQ92) as the orthologous Ca2+-activated apical epithelial H2O2-generating NADPH oxidase in airway, urothelium, and keratinocytes.

Boundary: This module models the two-step apical H2O2-generating core—(1) DUOXA1-mediated ER exit and apical plasma membrane targeting of DUOX1 and (2) Ca2+-activated, NADPH-dependent extracellular H2O2 production by DUOX1. Downstream consumers of DUOX1-derived H2O2 (secreted mucosal lactoperoxidase [LPO] in the airway surface liquid and redox-sensitive epithelial signaling effectors such as Src/ADAM17/EGFR) lie downstream of the modeled H2O2 generation step. Unlike C. elegans BLI-3, vertebrate DUOX1 lacks heme-coordinating histidines in its N-terminal peroxidase-homology domain (PHD) and has no intrinsic peroxidase activity (GO:0004601), although domain-based electronic mappings (InterPro:IPR010255) continue to project GO:0004601 and GO:0006979 onto vertebrate DUOX1/DUOX2. Member genes with reviews in this repository: human/DUOX1 (UniProtKB:Q9NRD9), mouse/Duox1 (UniProtKB:A2AQ92).

3Nodes
2Parts
0Variant Sets
0Variants
2Annotons
1Connections

Derived QC

Recommended-field compliance

100.0% recommended fields populated

All recommended fields populated.

Module deep research

✗ none found

No MODULE:mucosal_duox1_lactoperoxidase_antimicrobial_system deep-research report alongside the module YAML.

Leaf nodes lacking representative members

✓ every leaf node grounds to a representative protein.

Template conformance

✓ every declared conforms_to bundle matches its template motif.

Function consistency and core coverage

2 gene-function check(s) reflected in core functions · 0 conflict(s) · 3 evidence or coverage gap(s) (6 comparison(s))

Retained noncore functions are reported separately; they do not require promotion to core functions. Support from representative genes does not establish conservation across the whole family. Missing reviews or identifiers leave a claim unverified.

AnnotonParticipantFunctionAssessment
duoxa1_maturation_factor DUOXA1 (human)
UniProtKB:Q1HG43
Family Representative 		enzyme activator activity
GO:0008047 		Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked.
duoxa1_maturation_factor Duoxa1 (mouse)
UniProtKB:Q8BG94
Family Representative 		enzyme activator activity
GO:0008047 		Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked.
duox1_catalytic_oxidase DUOX1 (human)
UniProtKB:Q9NRD9
Family Representative 		NAD(P)H oxidase H2O2-forming activity
GO:0016174 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
duox1_catalytic_oxidase Duox1 (mouse)
UniProtKB:A2AQ92
Family Representative 		NAD(P)H oxidase H2O2-forming activity
GO:0016174 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
duoxa1_maturation_factor Dual oxidase maturation factor 1 (DUOXA1)
Family 		enzyme activator activity
GO:0008047 		Family Id Missing
The family has no identifier linking it to a curated family review.
duox1_catalytic_oxidase Dual oxidase 1 (DUOX1)
PANTHER:PTHR11972:SF75
Family 		NAD(P)H oxidase H2O2-forming activity
GO:0016174 		Family Supported
Family review supports GO:0016174 for PANTHER:PTHR11972:SF75. Direct Ca2+-regulated (or constitutive in NOX4) NADPH-dependent reduction of O2 to hydrogen peroxide (GO:0016174) is specific to the metazoan DUOX1 (PANTHER:PTHR11972:SF75), DUOX2 (PANTHER:PTHR11972:SF67), invertebrate DUOX/BLI-3 (PANTHER:PTHR11972:SF175), and NOX4 (PANTHER:PTHR11972:SF206) branches and does not apply across the ferric-reductase or superoxide-forming NOX branches of PTHR11972.

Gene-review completeness (2/4 grounded genes reviewed)

2 complete review(s) · 1 with deep research · 2 missing review · 1 reviewed but lacking deep research

Gene Review Complete Deep research
Duox1 A2AQ92 ✓ ✓ ✗
DUOX1 Q9NRD9 ✓ ✓ ✓
DUOXA1 (human) Q1HG43 ✗ — —
Duoxa1 (mouse) Q8BG94 ✗ — —

Details

Context
MammaliaNCBITaxon:40674 Homo sapiensNCBITaxon:9606 Mus musculusNCBITaxon:10090
respiratory system epitheliumUBERON:0004807 urotheliumUBERON:0000365 skin epidermisUBERON:0001003
apical plasma membraneGO:0016324 endoplasmic reticulum membraneGO:0005789
Mucosal DUOX1-DUOXA1 hydrogen peroxide generator and epithelial signaling moduleBiological Processmucosal_duox1_lactoperoxidase_antimicrobial_system

DUOXA1 chaperones and forms a stable apical plasma membrane complex with DUOX1, enabling Ca2+-activated, NADPH-dependent generation of extracellular H2O2 for mucosal host defense and redox-dependent epithelial wound repair.

NAD(P)H oxidase H2O2-forming activityGO:0016174 hydrogen peroxide biosynthetic processGO:0050665 innate immune response in mucosaGO:0002227 wound healingGO:0042060
Context
MammaliaNCBITaxon:40674 Homo sapiensNCBITaxon:9606 Mus musculusNCBITaxon:10090
respiratory system epitheliumUBERON:0004807 urotheliumUBERON:0000365 skin epidermisUBERON:0001003
apical plasma membraneGO:0016324 endoplasmic reticulum membraneGO:0005789

Connections

DUOXA1 heterodimerization with DUOX1 enables ER exit, apical membrane targeting, and catalytic H2O2 production by DUOX1.
Part 1: ER-to-apical membrane maturation and heterodimer assembly of DUOX1
DUOXA1-mediated maturation and apical targeting of DUOX1Regulatory Stepduoxa1_maturation_step

Annotons

DUOXA1 maturation factor and obligate heterodimer partner
duoxa1_maturation_factor
Participant: Family: Dual oxidase maturation factor 1 (DUOXA1)
Family:
Dual oxidase maturation factor 1 (DUOXA1)
Representative Members: DUOXA1 (human)UniProtKB:Q1HG43 Duoxa1 (mouse)UniProtKB:Q8BG94

Function

enzyme activator activityGO:0008047 Forms a 1:1 transmembrane complex with DUOX1, capping the peroxidase-homology domain and enabling ER exit, Golgi glycosylation, and catalytic competence at the apical membrane.

Processes

protein targeting to plasma membraneGO:0072659 hydrogen peroxide biosynthetic processGO:0050665

Locations

apical plasma membraneGO:0016324 endoplasmic reticulum membraneGO:0005789

Obligate 5-TM partner subunit that stabilizes the DUOX1 peroxidase-homology domain and is required for DUOX1 ER exit and H2O2-generating activity.

PMID:33420071
Structures of human dual oxidase 1 complex in low-calcium and high-calcium states.
Co-expression of DUOXA1 with DUOX1 forms an active plasma membrane complex that catalyzes Ca2+-activated, NADPH-dependent H2O2 production.
we found the co-expression of DUOX1 and DUOXA1 resulted in cell membranes that showed robust calcium-activated, NADPH-dependent hydrogen peroxide production detected by the Amplex Red assay
PMID:39126279
The NADPH oxidases DUOX1 and DUOX2 are sorted to the apical plasma membrane in epithelial cells via their respective maturation factors DUOXA1 and DUOXA2.
DUOXA1 specifically mediates sorting of DUOX1 to the apical plasma membrane in polarized epithelial cells.
Here we show that DUOX1 and DUOX2 are correctly sorted to the apical membrane via the membrane-spanning DUOX maturation proteins DUOXA1 and DUOXA2, respectively, when co-expressed in MDCK epithelial cells.
Part 2: Ca2+-activated apical NADPH oxidation and extracellular H2O2 generation
DUOX1 Ca2+-activated NADPH-dependent H2O2 productionReactionduox1_h2o2_generation_step

Annotons

DUOX1 Ca2+-dependent H2O2-generating NADPH oxidase
duox1_catalytic_oxidase
Participant: Family: Dual oxidase 1 (DUOX1)
Family:
Dual oxidase 1 (DUOX1)PANTHER:PTHR11972:SF75
Representative Members: DUOX1 (human)UniProtKB:Q9NRD9 Duox1 (mouse)UniProtKB:A2AQ92

Function

NAD(P)H oxidase H2O2-forming activityGO:0016174 Catalyzes Ca2+-activated electron transfer from cytosolic NADPH through FAD and two intramembrane b-type hemes to O2, releasing H2O2 at the extracellular face of the apical membrane.

Processes

hydrogen peroxide biosynthetic processGO:0050665 innate immune response in mucosaGO:0002227 wound healingGO:0042060

Locations

apical plasma membraneGO:0016324

Catalytic 7-TM flavocytochrome subunit that senses intracellular Ca2+ via two EF-hand motifs and generates extracellular H2O2 for mucosal host defense and epithelial redox signaling.

PMID:32929281
Structures of mouse DUOX1-DUOXA1 provide mechanistic insights into enzyme activation and regulation.
Mouse DUOX1-DUOXA1 transfers electrons from cytosolic NADPH through FAD and two intramembrane hemes to reduce O2 to H2O2, while lacking heme density and heme-coordinating histidines in its extracellular PHD.
the facts that no heme density is observed in the cryo-EM map and histidines needed for heme coordination are missing in the putative binding pocket strongly suggest that the PHD domain of DUOX1 lacks heme-dependent peroxidase activity.
PMID:33420071
Structures of human dual oxidase 1 complex in low-calcium and high-calcium states.
Human DUOX1 lacks the heme-coordinating histidine in the peroxidase-homology domain and shows no heme density in the cryo-EM structure.
key residues for heme binding, such as the heme ligand histidine, are missing in the PHD of hDUOX1. Indeed, we did not observe any heme density in the structure of hDUOX1 PHD, suggesting PHD is probably not enzymatic functional in term of peroxidase activity.