ERO1A

UniProt ID: Q96HE7
Organism: Homo sapiens
Review Status: COMPLETE
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Gene Description

ERO1A (ERO1-like protein alpha, formerly ERO1L; endoplasmic reticulum oxidoreductin-1 alpha) is an ER membrane-associated, FAD-dependent flavoprotein sulfhydryl oxidase (EC 1.8.3.2) that drives oxidative protein folding in the endoplasmic reticulum. It reoxidizes the protein disulfide isomerase P4HB/PDI, regenerating PDI's active-site disulfide so that PDI can catalyze further rounds of disulfide-bond formation in nascent secretory proteins; the electrons abstracted are passed via bound FAD to molecular oxygen, producing hydrogen peroxide. It is a peripheral membrane protein on the lumenal side of the ER, retained there through its interaction with ERP44, and is also detected in the Golgi lumen and secreted. Its enzymatic activity is tightly regulated by intramolecular regulatory disulfide bonds (involving Cys94/Cys99/Cys104/Cys131) to limit reactive-oxygen-species accumulation, and is further tuned by FAM20C-mediated phosphorylation at Ser145. ERO1A is induced by hypoxia via the HIF pathway and during the unfolded protein response. Through oxidative folding it supports maturation of disulfide-rich secretory cargo such as immunoglobulins, and participates in ER-stress responses, cholera-toxin retrotranslocation, and ER redox homeostasis.

Existing Annotations Review

GO Term Evidence Action Reason
GO:0005789 endoplasmic reticulum membrane
IBA
GO_REF:0000033
ACCEPT
Summary: ERO1A is a peripheral ER membrane protein acting on the lumenal side; this is its primary site of action and is well supported experimentally and by phylogenetic inference across the EROs family.
Reason: The ER membrane (lumenal side) is the documented site of action for ERO1A, where it reoxidizes PDI; corroborated by direct evidence.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
SUBCELLULAR LOCATION: Endoplasmic reticulum membrane
GO:0005576 extracellular region
IEA
GO_REF:0000044
KEEP AS NON CORE
Summary: A secreted/extracellular pool of ERO1A has been reported, but this is peripheral to its core ER oxidoreductase function.
Reason: UniProt records a secreted pool, so the localization is not wrong, but it is a minor/secondary location relative to the ER where ERO1A performs its catalytic role.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
Golgi apparatus lumen
GO:0005783 endoplasmic reticulum
IEA
GO_REF:0000120
ACCEPT
Summary: ER localization is correct and the principal compartment for ERO1A.
Reason: ERO1A is an ER-resident oxidoreductase; this localization is directly supported.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
SUBCELLULAR LOCATION: Endoplasmic reticulum membrane
GO:0005789 endoplasmic reticulum membrane
IEA
GO_REF:0000044
ACCEPT
Summary: Electronic localization to ER membrane, consistent with the IBA and experimental evidence.
Reason: Correct compartment; ERO1A is a peripheral ER membrane protein on the lumenal side.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
Peripheral membrane protein
GO:0005796 Golgi lumen
IEA
GO_REF:0000044
KEEP AS NON CORE
Summary: ERO1A is detected in the Golgi lumen, where it is a FAM20C substrate, but this is secondary to its ER function.
Reason: Golgi lumen localization is documented (FAM20C phosphorylation occurs in the Golgi) but peripheral to the core ER oxidoreductase activity.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
Golgi apparatus lumen
GO:0015035 protein-disulfide reductase activity
IEA
GO_REF:0000120
MARK AS OVER ANNOTATED
Summary: This term asserts a disulfide REDUCTASE activity. ERO1A is mechanistically an OXIDASE that reoxidizes PDI (i.e. forms disulfides and consumes reducing equivalents), not a reductase. The reductase term is an over-annotation, likely an electronic transfer that mislabels the directionality.
Reason: ERO1A oxidizes PDI and passes electrons to O2 generating H2O2; it does not function as a protein-disulfide reductase. The catalytic direction recorded by UniProt is dithiol oxidation, contradicting a reductase assignment.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
Efficiently reoxidizes P4HB/PDI, the enzyme catalyzing protein disulfide formation, in order to allow P4HB to sustain additional rounds of disulfide formation.
GO:0016971 flavin-dependent sulfhydryl oxidase activity
IEA
GO_REF:0000116
ACCEPT
Summary: This is the precise core molecular function of ERO1A - a FAD-dependent sulfhydryl oxidase catalyzing dithiol + O2 = disulfide + H2O2 (RHEA:59116). The falcon deep research independently describes the same electron-flow mechanism with O2 as the terminal electron acceptor.
Reason: Directly matches the catalytic activity and FAD cofactor of ERO1A and is supported experimentally (EXP entries from PMID:11707400, PMID:29858230).
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
Reaction=[protein]-dithiol + O2 = [protein]-disulfide + H2O2
file:human/ERO1A/ERO1A-deep-research-falcon.md
ERO1A then re-oxidizes reduced PDI by accepting electrons through its FAD cofactor, with molecular oxygen (Oβ‚‚) serving as the terminal electron acceptor
GO:0016972 thiol oxidase activity
IEA
GO_REF:0000120
ACCEPT
Summary: Thiol oxidase activity is the broader parent of ERO1A's flavin-dependent sulfhydryl oxidase activity; correct but less specific.
Reason: Correctly captures ERO1A's oxidase activity; the IDA-supported version of the same term (PMID:11707400) confirms it.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
EC=1.8.3.2
GO:0030425 dendrite
IEA
GO_REF:0000120
MARK AS OVER ANNOTATED
Summary: Dendritic localization is inferred only by similarity to the mouse ortholog (Q8R4A1) and is not established for human ERO1A.
Reason: This is a by-similarity transfer from the rodent ortholog for a neuronal context; it is not a core function and is unsupported by direct human evidence.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
In neurons, it localizes to dendrites (By
GO:0034975 protein folding in endoplasmic reticulum
IEA
GO_REF:0000002
KEEP AS NON CORE
Summary: ERO1A enables oxidative protein folding in the ER; protein folding in the ER is a valid downstream biological process outcome of its oxidase activity.
Reason: Protein folding in the ER is a process consequence of ERO1A's oxidase activity rather than its direct molecular function; appropriate as a non-core process annotation.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
Oxidoreductase involved in disulfide bond formation in the endoplasmic reticulum.
GO:0071949 FAD binding
IEA
GO_REF:0000002
ACCEPT
Summary: ERO1A is a flavoprotein that binds FAD as its cofactor; multiple FAD binding residues are defined in the crystal structure.
Reason: FAD is the documented cofactor with mapped binding sites (PubMed:20834232, PDB 3AHQ/3AHR); FAD binding is integral to the oxidase mechanism.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
Name=FAD; Xref=ChEBI:CHEBI:57692
GO:0005515 protein binding
IPI
PMID:17170699
ERp57 is essential for efficient folding of glycoproteins sh...
KEEP AS NON CORE
Summary: IntAct interaction with PDIA3/ERp57 (P30101). Bare protein binding is uninformative; it records a real ER-oxidoreductase interaction but is non-core (and note PMID:11707400 found ERO1A does not alter ERp57 redox state).
Reason: Records a genuine physical interaction within the ER oxidoreductase network, but the uninformative protein binding term should not be elevated to core function.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
Q96HE7; P30101: PDIA3
GO:0005515 protein binding
IPI
PMID:20802462
Disulphide production by Ero1Ξ±-PDI relay is rapid and effect...
KEEP AS NON CORE
Summary: IntAct interactions with P4HB/PDI (P07237) and PDIA3 (P30101), the physiological substrates ERO1A reoxidizes. The bare protein binding term is uninformative but the underlying P4HB interaction is biologically central; the falcon deep research notes ERO1A binds PDI with the highest affinity among ER thiol isomerases (Kd 1.7 uM), consistent with PDI being its preferred direct substrate.
Reason: The P4HB interaction underlies ERO1A's catalytic substrate relationship, but the generic protein binding term is uninformative and the informative function is captured by the oxidase MF terms.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
Q96HE7; P07237: P4HB
file:human/ERO1A/ERO1A-deep-research-falcon.md
ERO1A exhibits strong substrate selectivity for PDI over other ER oxidoreductases. Quantitative binding studies demonstrate that ERO1A binds PDI with highest affinity (Kd = 1.7 ΞΌM)
GO:0005515 protein binding
IPI
PMID:25416956
A proteome-scale map of the human interactome network.
KEEP AS NON CORE
Summary: High-throughput yeast two-hybrid interactome capturing an ERO1A-APPBP2 (Q92624) interaction; an isolated binary interaction unrelated to ERO1A's oxidase function.
Reason: Bare protein binding from a large-scale binary interactome screen; records an interaction but is uninformative and not part of the core function.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
Q96HE7; Q92624: APPBP2
GO:0005515 protein binding
IPI
PMID:32296183
A reference map of the human binary protein interactome.
KEEP AS NON CORE
Summary: Binary interactome map capturing an ERO1A-LHX4 (Q969G2) interaction; a single high-throughput interaction with a homeobox transcription factor unrelated to ERO1A's ER function.
Reason: Bare protein binding from a reference binary interactome; uninformative and not part of ERO1A's core oxidative-folding function.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
Q96HE7; Q969G2: LHX4
GO:0016491 oxidoreductase activity
IEA
GO_REF:0000107
ACCEPT
Summary: ERO1A is an oxidoreductase; this is a correct but very general parent term.
Reason: Correct high-level molecular function, subsumed by the more specific flavin-dependent sulfhydryl oxidase activity that is the core function.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
Oxidoreductase involved in disulfide bond formation in the endoplasmic reticulum.
GO:0034976 response to endoplasmic reticulum stress
IEA
GO_REF:0000107
KEEP AS NON CORE
Summary: ERO1A is induced during the UPR and participates in ER-stress responses; this is a plausible process annotation transferred from the mouse ortholog.
Reason: ERO1A is part of the ER stress/UPR program but this is a downstream/contextual process rather than its core molecular function.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
Plays an important role in ER stress-induced, CHOP-dependent apoptosis
GO:0051209 release of sequestered calcium ion into cytosol
IEA
GO_REF:0000107
KEEP AS NON CORE
Summary: ERO1A promotes ER Ca2+ release by activating IP3R1 during ER-stress apoptosis; this is inferred from the mouse ortholog and is a specialized downstream role. The falcon deep research corroborates that ERO1A modulates ER Ca2+ release via IP3R (and RyR) channels.
Reason: A genuine but context-specific (ER-stress apoptosis) downstream effect inferred by similarity; non-core relative to the oxidase function.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
by activating the inositol 1,4,5-trisphosphate receptor IP3R1
file:human/ERO1A/ERO1A-deep-research-falcon.md
ERO1A triggers calcium release from the ER to the cytosol and mitochondria by modulating IP3R and RyR calcium channels
GO:0070059 intrinsic apoptotic signaling pathway in response to endoplasmic reticulum stress
IEA
GO_REF:0000107
KEEP AS NON CORE
Summary: ERO1A contributes to CHOP-dependent ER-stress apoptosis (via IP3R1); inferred from the mouse ortholog.
Reason: A documented but specialized downstream signaling role; non-core relative to the core oxidase activity.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
Plays an important role in ER stress-induced, CHOP-dependent apoptosis by activating the inositol 1,4,5-trisphosphate receptor IP3R1.
GO:0071456 cellular response to hypoxia
IEA
GO_REF:0000107
KEEP AS NON CORE
Summary: ERO1A is hypoxia-inducible via the HIF pathway; participation in the cellular hypoxia response is supported. The falcon deep research corroborates that ERO1A is transcriptionally induced by HIF-1alpha under hypoxia (notably in tumor microenvironments).
Reason: ERO1A is a hypoxia-induced gene, so a hypoxia-response process annotation is reasonable, but this is a regulatory/contextual process rather than its core function.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
Stimulated by hypoxia; suggesting that it is regulated via the HIF-pathway.
file:human/ERO1A/ERO1A-deep-research-falcon.md
ERO1A expression is strongly induced by hypoxia through hypoxia-inducible factor 1Ξ± (HIF-1Ξ±)
GO:0016971 flavin-dependent sulfhydryl oxidase activity
EXP
PMID:11707400
Manipulation of oxidative protein folding and PDI redox stat...
ACCEPT
Summary: Experimentally supported FAD-dependent sulfhydryl oxidase activity - ERO1A oxidizes PDI to drive disulfide bond formation in immunoglobulins.
Reason: Strong experimental evidence (selective oxidation of PDI); this is the core molecular function of ERO1A.
Supporting Evidence:
PMID:11707400
both human Ero1-Lalpha and Ero1-Lbeta (hEROs) facilitate disulfide bond formation in immunoglobulin subunits by selectively oxidizing PDI
GO:0016971 flavin-dependent sulfhydryl oxidase activity
EXP
PMID:29858230
Secretory kinase Fam20C tunes endoplasmic reticulum redox st...
ACCEPT
Summary: Experimentally supported FAD-dependent sulfhydryl oxidase activity; ERO1A activity is tuned by FAM20C phosphorylation and required for immunoglobulin folding.
Reason: Core molecular function with direct experimental support; phosphomimetic S145E increases enzyme activity and accelerates immunoglobulin folding.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
Shows two-fold increase in enzyme activity. Accelerates immunoglobulin folding.
GO:0016972 thiol oxidase activity
IDA
PMID:11707400
Manipulation of oxidative protein folding and PDI redox stat...
ACCEPT
Summary: Direct-assay thiol oxidase activity (parent of the flavin-dependent sulfhydryl oxidase term); ERO1A oxidizes PDI thiols.
Reason: IDA evidence for oxidase activity; correct, though the flavin-dependent sulfhydryl oxidase term is the most precise descriptor.
Supporting Evidence:
PMID:11707400
Disulfide bond formation is controlled by hEROs, which stand at a crucial point of an electron-flow starting from nascent secretory proteins and passing through PDI.
GO:0016972 thiol oxidase activity
IDA
PMID:29858230
Secretory kinase Fam20C tunes endoplasmic reticulum redox st...
ACCEPT
Summary: Direct-assay thiol oxidase activity confirmed in the FAM20C-phosphorylation study.
Reason: IDA-supported oxidase activity; consistent core molecular function.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
EC=1.8.3.2
GO:0005515 protein binding
IPI
PMID:29858230
Secretory kinase Fam20C tunes endoplasmic reticulum redox st...
KEEP AS NON CORE
Summary: IntAct interaction with ERP44 (Q9BS26), the partner that retains ERO1A in the ER. Bare protein binding is uninformative but the ERP44 interaction is biologically meaningful (ER retention).
Reason: A real, functionally important interaction (ER retention via ERP44), but the generic protein binding term is uninformative and should not be elevated to a core molecular function.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
Interacts with ERP44; the interaction results in retention of ERO1A in the endoplasmic reticulum
GO:0005576 extracellular region
IDA
PMID:29858230
Secretory kinase Fam20C tunes endoplasmic reticulum redox st...
KEEP AS NON CORE
Summary: Direct evidence for a secreted/extracellular pool of ERO1A.
Reason: A genuine secondary localization (secreted), peripheral to the ER site of catalytic action.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
Secreted
GO:0005783 endoplasmic reticulum
IDA
PMID:29858230
Secretory kinase Fam20C tunes endoplasmic reticulum redox st...
ACCEPT
Summary: Direct evidence for ER localization, the principal compartment of ERO1A.
Reason: IDA-supported ER localization, the core compartment for ERO1A's oxidase function.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
SUBCELLULAR LOCATION: Endoplasmic reticulum membrane
GO:0005796 Golgi lumen
IDA
PMID:29858230
Secretory kinase Fam20C tunes endoplasmic reticulum redox st...
KEEP AS NON CORE
Summary: Direct evidence for a Golgi-lumen pool where ERO1A is phosphorylated by FAM20C.
Reason: Genuine secondary localization (Golgi) relevant to FAM20C regulation but peripheral to the ER catalytic role.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
Golgi apparatus lumen
GO:0006457 protein folding
IMP
PMID:29858230
Secretory kinase Fam20C tunes endoplasmic reticulum redox st...
KEEP AS NON CORE
Summary: ERO1A is required for proper folding of immunoglobulins; protein folding is a valid downstream process outcome of its oxidase activity.
Reason: Protein folding is the biological-process consequence of ERO1A-driven oxidative folding, downstream of its core oxidase molecular function.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
Required for the proper folding of immunoglobulins
GO:0045454 cell redox homeostasis
IMP
PMID:29858230
Secretory kinase Fam20C tunes endoplasmic reticulum redox st...
ACCEPT
Summary: ERO1A is a central determinant of ER redox state; its activity is tightly regulated to balance oxidation and limit ROS.
Reason: ERO1A genuinely sets/balances ER redox homeostasis (regulatory disulfides and FAM20C tuning); a core biological process for this enzyme.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
Enzyme activity is tightly regulated to prevent the accumulation of reactive oxygen species in the endoplasmic reticulum.
GO:0016020 membrane
HDA
PMID:19946888
Defining the membrane proteome of NK cells.
KEEP AS NON CORE
Summary: High-throughput membrane proteome detection; ERO1A is a peripheral membrane protein, so a generic membrane localization is consistent but uninformative.
Reason: Generic membrane localization from a proteomic survey; correct but far less specific than ER membrane.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
Peripheral membrane protein
GO:0005788 endoplasmic reticulum lumen
TAS
Reactome:R-HSA-3341296
ACCEPT
Summary: Reactome places ERO1A in the ER lumen; ERO1A acts on the lumenal side of the ER membrane, so this is consistent with its site of action.
Reason: ERO1A is a lumenal-side ER protein; ER lumen localization is consistent with its function and curated by Reactome.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
Lumenal side
GO:0034976 response to endoplasmic reticulum stress
ISS
GO_REF:0000024
KEEP AS NON CORE
Summary: ISS-transferred ER-stress-response role from the mouse ortholog; consistent with ERO1A's UPR induction.
Reason: Redundant with the IEA ER-stress annotation; a plausible downstream/contextual process, non-core.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
Plays an important role in ER stress-induced, CHOP-dependent apoptosis
GO:0051209 release of sequestered calcium ion into cytosol
ISS
GO_REF:0000024
KEEP AS NON CORE
Summary: ISS-transferred Ca2+-release role (via IP3R1) from the mouse ortholog.
Reason: Specialized downstream effect during ER-stress apoptosis inferred by similarity; non-core.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
by activating the inositol 1,4,5-trisphosphate receptor IP3R1
GO:0070059 intrinsic apoptotic signaling pathway in response to endoplasmic reticulum stress
ISS
GO_REF:0000024
KEEP AS NON CORE
Summary: ISS-transferred ER-stress apoptosis role from the mouse ortholog.
Reason: Documented but specialized downstream signaling role; non-core relative to the oxidase activity.
Supporting Evidence:
file:human/ERO1A/ERO1A-uniprot.txt
Plays an important role in ER stress-induced, CHOP-dependent apoptosis by activating the inositol 1,4,5-trisphosphate receptor IP3R1.
GO:0005783 endoplasmic reticulum
TAS
PMID:10671517
ERO1-L, a human protein that favors disulfide bond formation...
ACCEPT
Summary: Original characterization showing ERO1-L co-localizes with ER markers.
Reason: TAS from the founding paper directly establishes ER localization.
Supporting Evidence:
PMID:10671517
the product of the human ERO1-L gene co-localizes with ER markers and displays Endo-H-sensitive glycans
GO:0006457 protein folding
TAS
PMID:10671517
ERO1-L, a human protein that favors disulfide bond formation...
KEEP AS NON CORE
Summary: ERO1-L is involved in oxidative ER protein folding; protein folding is the downstream process of its oxidase activity.
Reason: A valid process annotation but downstream of the core oxidase molecular function.
Supporting Evidence:
PMID:10671517
ERO1-L is involved in oxidative ER protein folding in mammalian cells
GO:0009266 response to temperature stimulus
TAS
PMID:10671517
ERO1-L, a human protein that favors disulfide bond formation...
MARK AS OVER ANNOTATED
Summary: This term derives from ERO1-L complementing the temperature/DTT sensitivity of a yeast ero1-1 thermosensitive mutant - a heterologous complementation assay, not evidence that human ERO1A functions in a temperature-stimulus response.
Reason: The annotation over-interprets a yeast ts-mutant complementation experiment; it does not reflect a genuine temperature-response biological role for human ERO1A.
Supporting Evidence:
PMID:10671517
ERO1-L is able to complement several phenotypic traits of the yeast thermosensitive mutant ero1-1, including temperature and dithiothreitol sensitivity
GO:0016020 membrane
TAS
PMID:10671517
ERO1-L, a human protein that favors disulfide bond formation...
KEEP AS NON CORE
Summary: ERO1-L behaves as a membrane-associated protein in isolated microsomes.
Reason: Correct but generic membrane localization; the specific ER membrane term is preferred.
Supporting Evidence:
PMID:10671517
ERO1-L behaves as a type II integral membrane protein
GO:0043231 intracellular membrane-bounded organelle
TAS
PMID:10671517
ERO1-L, a human protein that favors disulfide bond formation...
KEEP AS NON CORE
Summary: Very general organelle localization term, subsumed by the specific ER annotations.
Reason: Uninformative high-level localization; correct but superseded by ER/ER membrane terms.
Supporting Evidence:
PMID:10671517
co-localizes with ER markers
GO:0005783 endoplasmic reticulum
IDA
PMID:10671517
ERO1-L, a human protein that favors disulfide bond formation...
ACCEPT
Summary: Direct evidence (co-localization with ER markers) for ER localization.
Reason: IDA-supported ER localization from the founding characterization.
Supporting Evidence:
PMID:10671517
co-localizes with ER markers
GO:0006457 protein folding
IDA
PMID:11707400
Manipulation of oxidative protein folding and PDI redox stat...
KEEP AS NON CORE
Summary: ERO1A facilitates disulfide-bond formation in immunoglobulin subunits; protein folding is a downstream process of its oxidase activity.
Reason: Valid downstream process annotation supported by direct evidence, but non-core relative to the oxidase molecular function.
Supporting Evidence:
PMID:11707400
hEROs) facilitate disulfide bond formation in immunoglobulin subunits by selectively oxidizing PDI

Core Functions

FAD-dependent endoplasmic-reticulum sulfhydryl oxidase that reoxidizes the protein disulfide isomerase P4HB/PDI, regenerating PDI's active site so it can catalyze further disulfide-bond formation in secretory proteins, with electrons passed via FAD to O2 producing H2O2.

Supporting Evidence:
  • file:human/ERO1A/ERO1A-uniprot.txt
    Efficiently reoxidizes P4HB/PDI, the enzyme catalyzing protein disulfide formation, in order to allow P4HB to sustain additional rounds of disulfide formation.
  • PMID:11707400
    both human Ero1-Lalpha and Ero1-Lbeta (hEROs) facilitate disulfide bond formation in immunoglobulin subunits by selectively oxidizing PDI

Sets and balances the redox state of the ER lumen, with activity tightly regulated by intramolecular regulatory disulfides (and FAM20C phosphorylation) to sustain oxidative protein folding while limiting reactive-oxygen-species accumulation.

Supporting Evidence:
  • file:human/ERO1A/ERO1A-uniprot.txt
    Enzyme activity is tightly regulated to prevent the accumulation of reactive oxygen species in the endoplasmic reticulum.

References

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Suggested Questions for Experts

Q: How is ERO1A activity coordinated with ERO1B and with PRDX4/peroxiredoxin-based H2O2 clearance to balance oxidative folding capacity against oxidative damage in different secretory tissues?

Q: What is the in vivo significance of the secreted/Golgi pools of ERO1A relative to its ER-lumenal oxidase role, and is FAM20C phosphorylation the main switch controlling them?

Suggested Experiments

Experiment: Reconstitute the ERO1A-PDI oxidation cycle in vitro with purified FAD-loaded ERO1A and P4HB, measuring O2 consumption and H2O2 production to quantify catalytic turnover and the effect of the regulatory disulfides and S145 phosphorylation.

Experiment: CRISPR knockout of ERO1A (and double knockout with ERO1B) in antibody-secreting cells followed by redox proteomics and immunoglobulin folding/secretion assays to define non-redundant substrate requirements.

Deep Research

Falcon

(ERO1A-deep-research-falcon.md)

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πŸ“š Additional Documentation

Notes

(ERO1A-notes.md)

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Pn Notes

(ERO1A-pn-notes.md)

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πŸ“„ View Raw YAML

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