IFI30

Existing Annotations Review

GO Term	Evidence	Action	Reason
GO:0016667 oxidoreductase activity, acting on a sulfur group of donors	IBA GO_REF:0000033	ACCEPT	Summary: GILT is established as a lysosomal thiol reductase with a thioredoxin-like CXXC active site that catalyzes disulfide bond reduction. This IBA annotation is well-supported by phylogenetic evidence and experimental data across species. Reason: This annotation accurately captures the core molecular function of GILT. The enzyme reduces disulfide bonds in the endolysosomal pathway using its CXXC active site motif. PMID:10639150 demonstrated the thiol reductase activity experimentally. PMID:17142755 confirmed that the thiol reductase activity of GILT is its essential function in MHC class II-restricted Ag processing. The IBA annotation based on phylogenetic inference is consistent with this experimental evidence. Supporting Evidence: PMID:10639150 We describe here a lysosomal thiol reductase optimally active at low pH and capable of catalyzing disulfide bond reduction both in vivo and in vitro. The active site, determined by mutagenesis, consists of a pair of cysteine residues separated by two amino acids, similar to other enzymes of the thioredoxin family. PMID:17142755 These studies demonstrate that the thiol reductase activity of GILT is its essential function in MHC class II-restricted Ag processing. file:human/IFI30/IFI30-deep-research-falcon.md GILT is a lysosomal thiol reductase that enzymatically reduces disulfide bonds of endocytosed proteins, facilitating antigen processing; described as the primary/only known reductase in the endocytic/lysosomal compartment.
GO:0005764 lysosome	IBA GO_REF:0000033	ACCEPT	Summary: GILT localizes to lysosomes via mannose-6-phosphate receptor-mediated trafficking. This is a core localization supported by multiple experimental studies. Reason: Lysosomal localization is a fundamental aspect of GILT function, enabling its activity at the acidic pH optimal for disulfide reduction. PMID:10639150 demonstrated mannose 6-phosphate receptor-mediated delivery. PMID:3136170 showed punctate fluorescence pattern in monocytes consistent with a vesicular subcellular location. The IBA annotation is well-supported. Supporting Evidence: PMID:10639150 After delivery into the endosomal/lysosomal system by the mannose 6-phosphate receptor, N- and C-terminal prosequences are removed. PMID:3136170 Indirect immunofluorescence microscopy reveals a punctate fluorescence pattern in monocytes consistent with a vesicular subcellular location. file:human/IFI30/IFI30-deep-research-falcon.md Localizes to the endocytic/MHC class II loading compartments (late endosomes/lysosomes) and shows maximal activity at acidic endolysosomal pH.
GO:0002376 immune system process	IEA GO_REF:0000043	MARK AS OVER ANNOTATED	Summary: This is a very broad GO term derived from UniProt keyword mapping. While GILT does function in immunity, a more specific annotation (MHC class II antigen processing) already exists and is more informative. Reason: The term "immune system process" (GO:0002376) is too general and uninformative. GILT's specific immune function is in antigen processing and presentation, which is already captured by the more specific annotations to GO:0019886 (MHC class II antigen presentation) and GO:0042590 (MHC class I cross-presentation). The automated IEA from UniProt keyword mapping is technically correct but redundant with more specific annotations that better characterize GILT's role. Supporting Evidence: PMID:10639150 The enzyme is expressed constitutively in antigen-presenting cells and induced by IFN-gamma in other cell types, suggesting a potentially important role in antigen processing.
GO:0005576 extracellular region	IEA GO_REF:0000044	KEEP AS NON CORE	Summary: GILT can be secreted as a disulfide-linked dimer, particularly by activated macrophages. This is a secondary localization, not the primary site of function. Reason: While GILT is primarily a lysosomal enzyme, the precursor form can be secreted as a disulfide-linked dimer. PMID:3136170 demonstrated that IP-30 is either secreted or converted intracellularly. The deep research notes that a minor disulfide-linked dimeric precursor can be secreted by activated macrophages and retains activity. However, the primary functional site is the lysosome, so this should be marked as non-core. Supporting Evidence: PMID:3136170 a 30-kDa polypeptide (referred to as IP-30) is either secreted or converted intracellularly into a 25-kDa protein file:human/IFI30/IFI30-deep-research-falcon.md A minor disulfide-linked dimeric precursor can be secreted by activated macrophages and retains activity
GO:0005764 lysosome	IEA GO_REF:0000120	ACCEPT	Summary: Duplicate annotation with IBA and IDA evidence. Lysosomal localization is well-supported and this IEA is consistent with experimental evidence. Reason: This IEA annotation is consistent with the IBA and IDA annotations for the same term. Duplicates with different evidence codes are acceptable in GO annotation as they represent independent lines of evidence. The combined automated method (GO_REF:0000120) correctly predicts lysosomal localization based on ortholog data (mouse GILT) and UniProt subcellular location vocabulary. Supporting Evidence: PMID:10639150 Enzymatic reduction of disulfide bonds in lysosomes: characterization of a gamma-interferon-inducible lysosomal thiol reductase (GILT).
GO:0016491 oxidoreductase activity	IEA GO_REF:0000043	ACCEPT	Summary: This is a parent term of the more specific GO:0016667 annotation. While correct, it is redundant with the more specific child term. Reason: This IEA annotation from UniProt keyword mapping is technically correct - GILT is an oxidoreductase. While GO:0016667 (oxidoreductase activity, acting on a sulfur group of donors) is more specific and informative, having the broader parent term from IEA is acceptable as it represents an independent inference pathway. The annotation is not wrong, just less specific than the experimental annotations. Supporting Evidence: PMID:10639150 We describe here a lysosomal thiol reductase optimally active at low pH and capable of catalyzing disulfide bond reduction both in vivo and in vitro.
GO:0016671 oxidoreductase activity, acting on a sulfur group of donors, disulfide as acceptor	IEA GO_REF:0000002	ACCEPT	Summary: This InterPro-based annotation is highly specific and accurately describes GILT's enzymatic function - reducing disulfide bonds using its thioredoxin-like active site. Reason: GO:0016671 is a child of GO:0016667 and specifies that the acceptor is a disulfide bond, which is precisely what GILT does. This is the most specific MF term applicable to GILT's catalytic activity. The InterPro domain (IPR004911 - Interferon-induced_GILT) correctly predicts this function. PMID:10639150 demonstrated experimentally that GILT reduces disulfide bonds in protein substrates. Supporting Evidence: PMID:10639150 Proteins internalized into the endocytic pathway are usually degraded. Efficient proteolysis requires denaturation, induced by acidic conditions within lysosomes, and reduction of inter- and intrachain disulfide bonds.
GO:0005515 protein binding	IPI PMID:25416956 A proteome-scale map of the human interactome network.	REMOVE	Summary: High-throughput interactome study detected GILT interactions with NOTCH2NLA and KRTAP4-12. These are from systematic Y2H screening but lack functional context. Reason: The term "protein binding" (GO:0005515) is uninformative and does not add value to GILT's functional annotation. PMID:25416956 is a large-scale proteome-wide interactome mapping study that used Y2H to detect binary protein-protein interactions. The interactions with NOTCH2NLA and KRTAP4-12 detected in this screen lack biological context and validation. These interactions do not inform us about GILT's function. Generic "protein binding" annotations from high-throughput screens without functional validation should be removed as they do not meet quality standards for informative annotations. Supporting Evidence: PMID:25416956 A proteome-scale map of the human interactome network.
GO:0005515 protein binding	IPI PMID:32296183 A reference map of the human binary protein interactome.	REMOVE	Summary: HuRI reference interactome study detected GILT interaction with TGM1 (transglutaminase 1). This is another high-throughput Y2H finding without functional validation. Reason: PMID:32296183 is the HuRI reference map of the human binary protein interactome, presenting protein-protein interactions from systematic Y2H screening. The detected interaction between GILT and TGM1 lacks functional validation and biological context. TGM1 is a keratinocyte transglutaminase involved in epidermal differentiation, and there is no obvious functional connection to GILT's role in antigen processing. Generic "protein binding" annotations from these high-throughput screens are uninformative and should be removed. If a more specific binding function were characterized, that would be informative, but "protein binding" alone provides no functional insight. Supporting Evidence: PMID:32296183 Apr 8. A reference map of the human binary protein interactome.
GO:0042590 antigen processing and presentation of exogenous peptide antigen via MHC class I	IEA GO_REF:0000107	ACCEPT	Summary: GILT facilitates MHC class I cross-presentation by reducing disulfide bonds in exogenous antigens. This annotation is transferred from mouse ortholog evidence. Reason: GILT's role in cross-presentation is documented in the literature. The deep research document notes that reduction by GILT can enhance transfer of endocytosed disulfide-containing antigens into the cytosol for class I cross-presentation. The UniProt function annotation states GILT also facilitates MHC class I-restricted recognition of exogenous antigens containing disulfide bonds. The IEA from Ensembl Compara ortholog transfer is supported by this biological understanding. Supporting Evidence: file:human/IFI30/IFI30-deep-research-falcon.md Reduction by GILT can enhance transfer of endocytosed disulfide-containing antigens into the cytosol for class I cross-presentation in certain settings.
GO:0016671 oxidoreductase activity, acting on a sulfur group of donors, disulfide as acceptor	IMP PMID:10639150 Enzymatic reduction of disulfide bonds in lysosomes: charact...	ACCEPT	Summary: Direct experimental demonstration of GILT's disulfide reductase activity using mutant phenotype analysis of the CXXC active site cysteines. Reason: PMID:10639150 is the seminal paper characterizing GILT's enzymatic function. The IMP (Inferred from Mutant Phenotype) evidence code is appropriate because the authors demonstrated that mutation of either Cys-72 or Cys-75 in the CXXC motif abolishes reductase activity. The abstract states the active site, determined by mutagenesis, consists of a pair of cysteine residues separated by two amino acids. This is strong experimental evidence for GO:0016671. Supporting Evidence: PMID:10639150 The active site, determined by mutagenesis, consists of a pair of cysteine residues separated by two amino acids, similar to other enzymes of the thioredoxin family.
GO:0019886 antigen processing and presentation of exogenous peptide antigen via MHC class II	TAS Reactome:R-HSA-2132295	ACCEPT	Summary: GILT's role in MHC class II antigen processing is its primary biological function. Reactome pathway annotation is well-supported by primary literature. Reason: This is a core function of GILT. The Reactome pathway R-HSA-2132295 describes MHC class II antigen presentation, within which GILT functions to reduce disulfide bonds in antigens to enable their processing. PMID:17142755 directly demonstrated that thiol reductase activity of GILT is its essential function in MHC class II-restricted Ag processing using GILT-deficient cell lines reconstituted with wild-type and mutant GILT. The deep research confirms GILT is the principal endocytic thiol reductase governing disulfide reduction in antigen processing. Supporting Evidence: PMID:17142755 These studies demonstrate that the thiol reductase activity of GILT is its essential function in MHC class II-restricted Ag processing. Reactome:R-HSA-2213240 The lysosomal thiol reductase gamma-IFN-inducible lysosomal thiol reductase (GILT) has been shown to facilitate MHC class II-restricted antigen (Ag) processing by breaking disulphide bonds.
GO:0016667 oxidoreductase activity, acting on a sulfur group of donors	EXP PMID:10639150 Enzymatic reduction of disulfide bonds in lysosomes: charact...	ACCEPT	Summary: Direct experimental evidence from the original characterization of GILT's enzymatic activity demonstrating its thiol reductase function. Reason: PMID:10639150 provided the first comprehensive characterization of GILT as a lysosomal thiol reductase. The paper demonstrated catalytic activity both in vivo and in vitro, showing optimal activity at acidic pH and identifying the CXXC active site through mutagenesis. This is strong primary experimental evidence for the molecular function annotation. Supporting Evidence: PMID:10639150 We describe here a lysosomal thiol reductase optimally active at low pH and capable of catalyzing disulfide bond reduction both in vivo and in vitro.
GO:0016667 oxidoreductase activity, acting on a sulfur group of donors	EXP PMID:17142755 Functional requirements for the lysosomal thiol reductase GI...	ACCEPT	Summary: Follow-up experimental study confirming GILT's thiol reductase activity is essential for its function in antigen processing. Reason: PMID:17142755 extended the findings of PMID:10639150 by demonstrating the functional requirements for GILT in MHC class II antigen processing. The study showed that mutation of either active site cysteine (Cys46 or Cys49 in mouse, corresponding to Cys72/75 in human) abrogated both reductase activity and antigen processing function. This provides additional experimental support for the GO:0016667 annotation. Supporting Evidence: PMID:17142755 Mutation of either Cys(46) or Cys(49) abrogated MHC class II processing of a GILT-dependent HEL epitope.
GO:0043202 lysosomal lumen	TAS Reactome:R-HSA-1031716	ACCEPT	Summary: GILT is localized to the lysosomal lumen where it functions at acidic pH. This Reactome annotation provides more specific localization than "lysosome." Reason: GO:0043202 (lysosomal lumen) is more specific than GO:0005764 (lysosome) and accurately describes where GILT functions. As a soluble glycoprotein delivered via the mannose-6-phosphate pathway, the mature form of GILT resides in the lysosomal lumen where it reduces disulfide bonds in internalized antigens. Reactome pathway R-HSA-1031716 (Expression of IFNG-stimulated genes) includes GILT as an IFN-gamma inducible protein localized to this compartment. Supporting Evidence: PMID:10639150 The enzyme is a soluble glycoprotein that is synthesized as a precursor. After delivery into the endosomal/lysosomal system by the mannose 6-phosphate receptor, N- and C-terminal prosequences are removed.
GO:0043202 lysosomal lumen	TAS Reactome:R-HSA-2213240	ACCEPT	Summary: Duplicate Reactome annotation for lysosomal lumen localization from the pathway specifically describing GILT's function in disulfide reduction. Reason: Reactome pathway R-HSA-2213240 (Reduction of disulphide bonds in MHC II antigens) specifically describes GILT's function and localization. The pathway summary states The lysosomal thiol reductase GILT has been shown to facilitate MHC class II-restricted antigen processing by breaking disulphide bonds. GILT is constitutively expressed in APCs. The reduction of disulphide bonds by mature GILT is optimal at acidic pH. This confirms lysosomal lumen localization. Supporting Evidence: Reactome:R-HSA-2213240 The lysosomal thiol reductase gamma-IFN-inducible lysosomal thiol reductase (GILT) has been shown to facilitate MHC class II-restricted antigen (Ag) processing by breaking disulphide bonds. GILT is constitutively expressed in APCs. The reduction of disulphide bonds by mature GILT is optimal at acidic pH
GO:0042590 antigen processing and presentation of exogenous peptide antigen via MHC class I	ISS GO_REF:0000024	ACCEPT	Summary: GILT facilitates cross-presentation to MHC class I based on sequence similarity to mouse ortholog with demonstrated function. Reason: The ISS (Inferred from Sequence Similarity) annotation is based on manual curator judgment of sequence similarity to mouse GILT (UniProtKB:Q9ESY9), which has demonstrated function in cross-presentation. UniProt notes that GILT also facilitates MHC class I-restricted recognition of exogenous antigens containing disulfide bonds by CD8+ T-cells or crosspresentation (By similarity). This functional inference is reasonable given the high conservation between human and mouse GILT and the shared domain architecture.
GO:0005764 lysosome	IDA PMID:10639150 Enzymatic reduction of disulfide bonds in lysosomes: charact...	ACCEPT	Summary: Direct experimental demonstration of GILT lysosomal localization via immunofluorescence and mannose-6-phosphate trafficking studies. Reason: PMID:10639150 directly demonstrated lysosomal localization of GILT. The paper showed that GILT is delivered to lysosomes via the mannose-6-phosphate receptor pathway, a hallmark of lysosomal protein targeting. The precursor is processed to the mature form upon arrival in the endosomal/lysosomal system. This IDA evidence is the strongest experimental support for lysosomal localization. Supporting Evidence: PMID:10639150 After delivery into the endosomal/lysosomal system by the mannose 6-phosphate receptor, N- and C-terminal prosequences are removed.
GO:0005576 extracellular region	TAS PMID:3136170 Molecular and biochemical characterization of a novel gamma-...	KEEP AS NON CORE	Summary: Original characterization showed GILT (IP-30) can be secreted, forming extracellular disulfide-linked dimers. Reason: PMID:3136170 demonstrated that the 30-kDa precursor (IP-30) can be secreted and forms extracellular dimers. While this is a valid localization, the primary functional site of GILT is the lysosome. Secretion appears to be a secondary phenomenon, particularly in activated macrophages during inflammation. Supporting Evidence: PMID:3136170 a 30-kDa polypeptide (referred to as IP-30) is either secreted or converted intracellularly into a 25-kDa protein
GO:0005764 lysosome	TAS PMID:3136170 Molecular and biochemical characterization of a novel gamma-...	ACCEPT	Summary: Original characterization suggested vesicular/lysosomal localization of IP-30 based on immunofluorescence microscopy. Reason: PMID:3136170 provided early evidence for lysosomal localization of GILT, showing punctate fluorescence pattern in monocytes consistent with a vesicular subcellular location. While this was suggestive rather than definitive, it was later confirmed by PMID:10639150 which demonstrated mannose-6-phosphate receptor-mediated delivery to lysosomes. Supporting Evidence: PMID:3136170 Indirect immunofluorescence microscopy reveals a punctate fluorescence pattern in monocytes consistent with a vesicular subcellular location. These data are consistent with IP-30 being a novel IFN gamma-inducible protein which may be lysosomal in location.
GO:0015035 protein-disulfide reductase activity	IDA PMID:10639150 Enzymatic reduction of disulfide bonds in lysosomes: charact...	NEW	Summary: GO:0015035 (protein-disulfide reductase activity) is more specific than GO:0016671 because it specifies that the substrates are proteins. GILT specifically reduces disulfide bonds in endocytosed protein antigens to facilitate their unfolding and proteolytic processing. Reason: This term is a more precise annotation than GO:0016671 because GILT's established physiological substrates are proteins - endocytosed antigens that require disulfide bond reduction for processing. PMID:10639150 demonstrated that GILT catalyzes disulfide bond reduction in proteins both in vivo and in vitro. The study showed efficient denaturation and reduction of internalized proteins is required for proteolysis in the lysosome. The child terms of GO:0015035 specify cofactors (glutathione, NAD(P)H), but GILT uses free cysteine transported into the lysosome as its electron donor, so the parent term GO:0015035 is most appropriate. Supporting Evidence: PMID:10639150 We describe here a lysosomal thiol reductase optimally active at low pH and capable of catalyzing disulfide bond reduction both in vivo and in vitro. The active site, determined by mutagenesis, consists of a pair of cysteine residues separated by two amino acids, similar to other enzymes of the thioredoxin family. PMID:17142755 These studies demonstrate that the thiol reductase activity of GILT is its essential function in MHC class II-restricted Ag processing. file:human/IFI30/IFI30-deep-research-falcon.md GILT is a lysosomal thiol reductase that enzymatically reduces disulfide bonds of endocytosed proteins, facilitating antigen processing. Known GILT-dependent substrates include disulfide-rich model antigens (e.g., hen egg lysozyme) and melanocyte differentiation antigens such as tyrosinase/TRP1.

Core Functions

GILT is a lysosomal thiol reductase that catalyzes the reduction of disulfide bonds in proteins internalized into the endocytic pathway. It contains a thioredoxin-like CXXC active site motif (Cys-72 and Cys-75) essential for catalytic activity. The enzyme shows optimal activity at acidic pH (pH 4-5), consistent with its lysosomal localization.

Molecular Function:

protein-disulfide reductase activity

Directly Involved In:

antigen processing and presentation of exogenous peptide antigen via MHC class II

Cellular Locations:

lysosomal lumen

References

GO_REF:0000002

Gene Ontology annotation through association of InterPro records with GO terms

The InterPro domain IPR004911 (Interferon-induced_GILT) correctly predicts the oxidoreductase activity acting on disulfide bonds.

GO_REF:0000024

Manual transfer of experimentally-verified manual GO annotation data to orthologs by curator judgment of sequence similarity

Cross-presentation function inferred from mouse ortholog Q9ESY9.

GO_REF:0000033

Annotation inferences using phylogenetic trees

IBA annotations for oxidoreductase activity and lysosomal localization are well-supported by the PANTHER phylogenetic tree and conserved function.

GO_REF:0000043

Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping

Keywords Oxidoreductase and Immunity correctly map to GO terms, though the immunity annotation is overly general.

GO_REF:0000044

Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt

Secreted and Lysosome keywords correctly predict extracellular and lysosomal localization.

GO_REF:0000107

Automatic transfer of experimentally verified manual GO annotation data to orthologs using Ensembl Compara

Cross-presentation function transferred from mouse ortholog.

GO_REF:0000120

Combined Automated Annotation using Multiple IEA Methods

Lysosomal localization correctly predicted from multiple sources.

PMID:10639150

Enzymatic reduction of disulfide bonds in lysosomes: characterization of a gamma-interferon-inducible lysosomal thiol reductase (GILT).

First comprehensive characterization of GILT enzymatic function.

"We describe here a lysosomal thiol reductase optimally active at low pH and capable of catalyzing disulfide bond reduction both in vivo and in vitro."
Demonstrated thiol reductase activity optimal at acidic pH.

"We describe here a lysosomal thiol reductase optimally active at low pH"
Identified CXXC active site through mutagenesis.

"The active site, determined by mutagenesis, consists of a pair of cysteine residues separated by two amino acids, similar to other enzymes of the thioredoxin family."
Showed mannose-6-phosphate receptor-mediated lysosomal targeting.

"After delivery into the endosomal/lysosomal system by the mannose 6-phosphate receptor, N- and C-terminal prosequences are removed."
Demonstrated processing from 35 kDa precursor to mature form.

"The enzyme is a soluble glycoprotein that is synthesized as a precursor."

PMID:17142755

Functional requirements for the lysosomal thiol reductase GILT in MHC class II-restricted antigen processing.

Demonstrated that GILT thiol reductase activity is essential for MHC class II antigen processing.

"These studies demonstrate that the thiol reductase activity of GILT is its essential function in MHC class II-restricted Ag processing."
Showed that active site cysteine mutations abolish antigen processing function.

"Mutation of either Cys(46) or Cys(49) abrogated MHC class II processing of a GILT-dependent HEL epitope."
Established functional link between enzymatic activity and immune function.

"These studies demonstrate that the thiol reductase activity of GILT is its essential function in MHC class II-restricted Ag processing."

PMID:25416956

A proteome-scale map of the human interactome network.

High-throughput Y2H screen detecting binary protein interactions including GILT interactions lacking functional validation.

PMID:3136170

Molecular and biochemical characterization of a novel gamma-interferon-inducible protein.

Original characterization of IP-30 (GILT) as IFN-gamma-inducible protein.

"A cDNA clone has been isolated from mRNA derived from the monocytic cell line U937, which detects an mRNA that is present and inducible by gamma-interferon"
Demonstrated secretion and intracellular processing.

"a 30-kDa polypeptide (referred to as IP-30) is either secreted or converted intracellularly into a 25-kDa protein"
Showed vesicular localization consistent with lysosomes.

"Indirect immunofluorescence microscopy reveals a punctate fluorescence pattern in monocytes consistent with a vesicular subcellular location."
Identified disulfide-linked dimeric forms.

"the extracellular form is involved in both intrachain and interchain disulfide bonding."

PMID:32296183

A reference map of the human binary protein interactome.

HuRI reference interactome with protein-protein interactions detected by Y2H, including GILT-TGM1 interaction without functional validation.

Reactome:R-HSA-1031716

Expression of IFNG-stimulated genes

GILT is an IFN-gamma-inducible gene.

Reactome:R-HSA-2132295

MHC class II antigen presentation

GILT functions in the MHC class II antigen presentation pathway.

Reactome:R-HSA-2213240

Reduction of disulphide bonds in MHC II antigens

GILT specifically catalyzes disulfide bond reduction in MHC II antigens.

"The lysosomal thiol reductase gamma-IFN-inducible lysosomal thiol reductase (GILT) has been shown to facilitate MHC class II-restricted antigen (Ag) processing by breaking disulphide bonds."
Optimal activity at acidic pH in lysosomes.

"The reduction of disulphide bonds by mature GILT is optimal at acidic pH"

Suggested Experiments

Experiment: Quantitative proteomics to identify GILT substrates in the endolysosomal pathway using trapping mutant approaches.

Hypothesis: GILT has specific substrate preferences beyond model antigens.

Experiment: Characterization of GILT's role in processing specific pathogen-derived antigens relevant to vaccine development.

Hypothesis: GILT-dependent antigen processing affects vaccine immunogenicity.

Experiment: Investigation of GILT's role in tumor antigen processing and implications for cancer immunotherapy.

Hypothesis: GILT expression levels in tumors correlate with antigen presentation efficiency and immunotherapy response.

Deep Research

Falcon

(IFI30-deep-research-falcon.md)

this with annotations you find in gene/protein databases, but these can be outdated or inaccurate. Falcon Edison Scientific Literature 14 citations 2025-12-20T14:32:07.681174

The research report should be a detailed narrative explaining the function, biological processes, and localization of the gene product. Citations should be given for all claims.

You should prioritize authoritative reviews and primary scientific literature when conducting research. You can supplement
this with annotations you find in gene/protein databases, but these can be outdated or inaccurate.

We are specifically interested in the primary function of the gene - for enzymes, what reaction is catalyzed, and what is the substrate specificity? For transporters, what is the substrate? For structural proteins or adapters, what is the broader structural role? For signaling molecules, what is the role in the pathway.

We are interested in where in or outside the cell the gene product carries out its function.

We are also interested in the signaling or biochemical pathways in which the gene functions. We are less interested in broad pleiotropic effects, except where these elucidate the precise role.

Include evidence where possible. We are interested in both experimental evidence as well as inference from structure, evolution, or bioinformatic analysis. Precise studies should be prioritized over high-throughput, where available.

Plan overview
- Verify identity and nomenclature to avoid gene symbol ambiguity and confirm Homo sapiens IFI30 (GILT) with correct domains/family. (hastings2006functionalrequirementsfor pages 1-2, hastings2011disulfidereductionin pages 1-2)
- Synthesize key concepts and definitions: enzymatic class, reaction chemistry, substrates, localization, induction, and pathway role. (hastings2006functionalrequirementsfor pages 1-2, hastings2011disulfidereductionin pages 1-2, west2013expandingrolesfor pages 7-10)
- Incorporate quantitative and mechanistic details from focused primary/authoritative reviews and studies; highlight applications and clinical relevance. (macy2022roleofgilt pages 17-19, west2013expandingrolesfor pages 4-6)
- Provide citations with URLs and publication years. Embed an evidence table artifact summarizing key facts.

Identity verification and nomenclature
- Target: IFI30 encodes gamma-interferon-inducible lysosomal thiol reductase (GILT; historically IP30), a member of the GILT family; the protein is an interferon-inducible lysosomal reductase with a thioredoxin-like CXXC active site. These attributes match the UniProt record P13284 for Homo sapiens. (hastings2006functionalrequirementsfor pages 1-2, hastings2011disulfidereductionin pages 1-2)
- Organism and family/domain context: Human GILT is an IFN-γ–inducible lysosomal enzyme localized to late endosomes/lysosomes, consistent with membership in a conserved family of lysosomal thiol reductases. (hastings2011disulfidereductionin pages 1-2, west2013expandingrolesfor pages 7-10)

Key concepts and definitions
- Enzyme class and reaction: GILT is a lysosomal thiol reductase that reduces intramolecular and intermolecular disulfide bonds in endocytosed proteins within the acidic endolysosomal pathway. This reduction exposes epitopes for subsequent proteolysis and loading onto MHC class II, and can facilitate cross-presentation to MHC class I. (hastings2011disulfidereductionin pages 1-2, west2013expandingrolesfor pages 7-10)
- Active site and structural features: GILT contains a thioredoxin-like CXXC motif; both active-site cysteines are essential for catalysis and antigen processing, as demonstrated by mutational analyses. (hastings2006functionalrequirementsfor pages 1-2, west2013expandingrolesfor pages 7-10)
- Maturation, trafficking, and pH dependence: GILT is synthesized as a ~35-kDa precursor with mannose-6-phosphate–dependent trafficking to endosomes, proteolytically processed to a ~28-kDa mature form that resides in late endosomes/lysosomes and exhibits maximal activity at acidic pH. A minor disulfide-linked dimeric precursor can be secreted by activated macrophages and retains activity. (hastings2006functionalrequirementsfor pages 1-2, hastings2011disulfidereductionin pages 1-2, west2013expandingrolesfor pages 4-6)
- Cellular expression and induction: Constitutively expressed in professional antigen-presenting cells (APCs; monocytes/macrophages, B cells, dendritic cells), inducible in non-APC cell types by IFN-γ via STAT1; induction is CIITA-independent. Inflammatory cytokines TNF-α and IL-1β can also upregulate GILT in certain contexts. (hastings2011disulfidereductionin pages 1-2, west2013expandingrolesfor pages 6-7, macy2022roleofgilt pages 15-17)

Pathways and substrates
- Antigen processing (MHC II): By reducing disulfide bonds, GILT promotes unfolding and proteolysis of antigens, enabling peptide loading onto MHC class II. Known GILT-dependent substrates include disulfide-rich model antigens (e.g., hen egg lysozyme) and melanocyte differentiation antigens such as tyrosinase/TRP1. (hastings2011disulfidereductionin pages 1-2, hastings2006functionalrequirementsfor pages 1-2)
- Cross-presentation (MHC I): Reduction by GILT can enhance transfer of endocytosed disulfide-containing antigens into the cytosol for class I cross-presentation in certain settings. (hastings2011disulfidereductionin pages 1-2, west2013expandingrolesfor pages 7-10)
- Pathogen/toxin modulation: GILT reduces and thereby activates the pore-forming toxin listeriolysin O (LLO) of Listeria monocytogenes; trapping mutants capture GILT–LLO adducts, demonstrating substrate engagement in vivo. (hastings2011disulfidereductionin pages 8-9)

Quantitative findings and statistics
- Self-peptidome effects: Quantitative MHC II peptidomics indicates a limited but detectable remodeling of the class II peptide repertoire by GILT; approximately 5% of peptides show higher abundance with GILT and ~2% are uniquely indicative of GILT status in certain analyses. (macy2022roleofgilt pages 17-19)
- Expression frequencies in melanoma lesions: Reported data show GILT+ malignant melanocytes in ~70% of primary and ~58% of metastatic melanoma samples; infiltrating APCs were uniformly GILT+, and halo nevi displayed GILT+ melanocytes in ~86% of cases. (macy2022roleofgilt pages 17-19)

Cellular and systems-level effects
- Redox homeostasis: GILT influences cellular redox, including glutathione balance (GSH/GSSG), mitochondrial function, and ROS production; it stabilizes SOD2 and can reduce inducible ROS in macrophages, linking lysosomal redox to broader cellular metabolism. (west2013expandingrolesfor pages 4-6, hastings2011disulfidereductionin pages 8-9)
- Secretion and inflammation: Activated macrophages can secrete an enzymatically active, disulfide-linked GILT precursor dimer; serum levels of precursor rise in systemic inflammatory settings, suggesting extracellular roles. (west2013expandingrolesfor pages 4-6)

Clinical and translational relevance
- Cancer immunology: High GILT expression and an intact MHC class II antigen presentation pathway associate with improved overall survival in melanoma cohorts; inflammatory cytokines (IFN-γ, TNF-α, IL-1β) correlate with and can induce GILT in melanoma cells. These findings support GILT as a favorable biomarker for MHC II pathway competence and potential responsiveness to immune surveillance. (macy2022roleofgilt pages 17-19)
- Therapeutic concepts and applications: Induction or ectopic expression of GILT in tumor cells enhances generation of antigenic peptides for CD4+ T-cell recognition, motivating strategies (e.g., whole-cell vaccines or IFN-γ–based conditioning) to boost tumor immunogenicity. (hastings2011disulfidereductionin pages 1-2, west2013expandingrolesfor pages 7-10)
- Infectious disease: Because GILT can activate bacterial hemolysins like LLO, it emerges as a host factor in intracellular pathogen biology; conversely, GILT’s role in antigen processing may enhance adaptive responses to disulfide-rich pathogen antigens. (hastings2011disulfidereductionin pages 8-9, hastings2011disulfidereductionin pages 1-2)

Expert opinions and authoritative analyses
- Reviews by Hastings & Cresswell and West & Cresswell establish GILT as the principal endocytic thiol reductase governing disulfide reduction in antigen processing and influencing cross-presentation and cellular redox, with broad implications across immunity to cancer and pathogens. (hastings2011disulfidereductionin pages 1-2, west2013expandingrolesfor pages 7-10, west2013expandingrolesfor pages 4-6)

Recent developments (note on 2023–2024 priority)
- While the foundational enzyme biochemistry and pathway role derive from earlier studies, recent translational observations captured in compiled sources emphasize the association of higher IFI30 expression with improved survival and with inflammatory cytokine signatures in melanoma, and document lesion-level frequencies of GILT positivity (primary/metastatic/halo nevi). Direct 2023–2024 human studies were limited in the retrieved evidence set, so the most current quantitative clinical links here derive from recent prior work. (macy2022roleofgilt pages 17-19)

Data provenance: URLs and publication years
- Functional requirements for GILT (human/murine systems): The Journal of Immunology (2006). https://doi.org/10.4049/jimmunol.177.12.8569 (Dec 2006). (hastings2006functionalrequirementsfor pages 1-2)
- Immunological functions and localization/pH: Antioxidants & Redox Signaling (2011). https://doi.org/10.1089/ars.2010.3684 (Aug 2011). (hastings2011disulfidereductionin pages 1-2)
- Expanding roles in immunity; cytokine induction, secretion, redox: Current Opinion in Immunology (2013). https://doi.org/10.1016/j.coi.2012.11.006 (Feb 2013). (west2013expandingrolesfor pages 4-6, west2013expandingrolesfor pages 7-10, west2013expandingrolesfor pages 6-7)
- Quantitative peptidome and clinical associations in melanoma and other contexts: compiled dissertation/analysis (2022) synthesizing mass spectrometry (~5%/2% effects) and lesion-level GILT positivity (70%/58%/86%). (2022). (macy2022roleofgilt pages 17-19)
- Pathogen/toxin substrate and trapping mutant evidence: Antioxidants & Redox Signaling (2011). https://doi.org/10.1089/ars.2010.3684 (Aug 2011). (hastings2011disulfidereductionin pages 8-9)

Limitations and open questions
- Structural biophysics beyond the CXXC motif (e.g., redox potential values, high-resolution structures specific to human GILT) and definitive 2023–2024 human clinical datasets were not available in the retrieved context. Future research should refine substrate scope/kinetics at lysosomal pH, quantify redox network interactions, and evaluate IFI30 as a predictive biomarker for immunotherapy.

Research artifact
| Aspect | Key finding (1-2 sentences) | Evidence/citation IDs | Source URL (if available) | Year |
|---|---|---:|---|---:|
| Identity verification (IFI30, GILT, human) | IFI30 (alias GILT/IP30) is the gamma-interferon-inducible lysosomal thiol reductase encoded in human cells and belongs to the GILT family. | (hastings2006functionalrequirementsfor pages 1-2, hastings2011disulfidereductionin pages 1-2, west2013expandingrolesfor pages 7-10) | https://doi.org/10.4049/jimmunol.177.12.8569 | 2006 |
| Enzymatic function | GILT is a lysosomal thiol reductase that enzymatically reduces disulfide bonds of endocytosed proteins, facilitating antigen processing; described as the primary/only known reductase in the endocytic/lysosomal compartment. | (hastings2006functionalrequirementsfor pages 1-2, hastings2011disulfidereductionin pages 1-2, west2013expandingrolesfor pages 7-10) | https://doi.org/10.1089/ars.2010.3684 | 2011 |
| Active site / structure (CXXC motif) | Catalytic activity depends on a thioredoxin-like CXXC active-site motif (essential cysteines); mutation of active-site cysteines abolishes reductase-dependent antigen processing. | (hastings2006functionalrequirementsfor pages 1-2, west2013expandingrolesfor pages 7-10) | https://doi.org/10.4049/jimmunol.177.12.8569 | 2006 |
| Processing / maturation | Synthesized as ~35 kDa precursor with mannose-6-phosphate targeting, proteolytically processed to ~28 kDa mature form that localizes to late endosomes/lysosomes; a minor secreted disulfide-linked dimer is enzymatically active. | (hastings2006functionalrequirementsfor pages 1-2, hastings2011disulfidereductionin pages 1-2) | https://doi.org/10.4049/jimmunol.177.12.8569 | 2006 |
| Cellular localization / pH optimum | Localizes to the endocytic/MHC class II loading compartments (late endosomes/lysosomes) and shows maximal activity at acidic endolysosomal pH. | (hastings2011disulfidereductionin pages 1-2, hastings2006functionalrequirementsfor pages 1-2) | https://doi.org/10.1089/ars.2010.3684 | 2011 |
| Induction / regulation | Expression is IFN-γ-inducible via STAT1 (CIITA-independent); other inflammatory cytokines (TNF-α, IL-1β) can also upregulate GILT in non-APC cells. | (hastings2011disulfidereductionin pages 1-2, west2013expandingrolesfor pages 6-7, macy2022roleofgilt pages 15-17) | https://doi.org/10.1016/j.coi.2012.11.006 | 2013 |
| Pathway role | GILT facilitates MHC class II-restricted antigen processing by reducing disulfide bonds to expose buried epitopes and also can promote cross-presentation for MHC I pathways. | (hastings2011disulfidereductionin pages 1-2, west2013expandingrolesfor pages 7-10) | https://doi.org/10.1089/ars.2010.3684 | 2011 |
| Substrates / examples | Demonstrated substrates include model proteins (hen egg lysozyme), melanocyte differentiation antigens (e.g., tyrosinase/TRP1), and activation/reduction of bacterial pore-forming toxins such as Listeria LLO. | (hastings2011disulfidereductionin pages 1-2, west2013expandingrolesfor pages 7-10, hastings2011disulfidereductionin pages 8-9) | https://doi.org/10.1089/ars.2010.3684 | 2011 |
| Redox / cellular effects | GILT influences cellular redox balance (affects GSH/GSSG ratios), stabilizes SOD2, alters ROS production and mitochondrial function, and precursor dimer secretion can occur in activated macrophages. | (west2013expandingrolesfor pages 4-6, hastings2011disulfidereductionin pages 1-2, hastings2011disulfidereductionin pages 8-9) | https://doi.org/10.1016/j.coi.2012.11.006 | 2013 |
| Quantitative peptidome effects | Mass-spectrometry studies report modest changes to the MHC II peptide repertoire: ~5% of peptides show >-fold changes linked to GILT presence and ~2% were uniquely indicative of GILT status in some analyses. | (macy2022roleofgilt pages 17-19, west2013expandingrolesfor pages 7-10) | | 2022 |
| Clinical / oncology associations | High GILT expression correlates with improved overall survival and intact MHC II pathway in melanoma specimens and is inducible in tumor cells (reported frequencies: e.g., ~70% primary, ~58% metastatic samples with GILT+ malignant melanocytes in some datasets). | (macy2022roleofgilt pages 17-19) | | 2022 |
| Applications (biomarker / immunotherapy) | GILT modulation is being investigated to enhance tumor antigen presentation (e.g., melanoma whole-cell vaccine strategies) and as a potential prognostic biomarker in cancer and inflammatory states. | (macy2022roleofgilt pages 17-19, west2013expandingrolesfor pages 4-6, west2013expandingrolesfor pages 7-10) | https://doi.org/10.1016/j.coi.2012.11.006 | 2013 |

Table: A concise evidence table summarizing verified identity, biochemical function, structural features, localization, regulation, pathway roles, substrates, quantitative effects, clinical associations, and applications of human IFI30/GILT with citations to source excerpts (context IDs).

Conclusions
Human IFI30 encodes GILT, the interferon-γ–inducible lysosomal thiol reductase that catalyzes disulfide bond reduction in the endolysosomal pathway. Its CXXC active site and acidic pH optimum support reduction of disulfide-rich antigens, enabling MHC class II presentation and sometimes cross-presentation. GILT is produced as a M6P-targeted 35-kDa precursor and processed to a 28-kDa lysosomal enzyme; it is constitutively expressed in APCs and inducible by IFN-γ (STAT1, CIITA-independent) and other inflammatory cytokines. Quantitatively, GILT modestly reshapes the MHC II peptidome and is detected in a majority of primary melanoma lesions, with higher expression associating with improved survival and with inflammatory cytokines. These properties motivate applications as a biomarker of intact MHC II antigen processing and as a lever to enhance tumor immunogenicity, while its roles in cellular redox and pathogen toxin activation underscore broader immunobiology. (hastings2006functionalrequirementsfor pages 1-2, hastings2011disulfidereductionin pages 1-2, west2013expandingrolesfor pages 7-10, macy2022roleofgilt pages 17-19, west2013expandingrolesfor pages 4-6, hastings2011disulfidereductionin pages 8-9, west2013expandingrolesfor pages 6-7)

References

(hastings2006functionalrequirementsfor pages 1-2): K. Taraszka Hastings, Rebecca L. Lackman, and Peter Cresswell. Functional requirements for the lysosomal thiol reductase gilt in mhc class ii-restricted antigen processing1. The Journal of Immunology, 177:8569-8577, Dec 2006. URL: https://doi.org/10.4049/jimmunol.177.12.8569, doi:10.4049/jimmunol.177.12.8569. This article has 73 citations.
(hastings2011disulfidereductionin pages 1-2): Karen Taraszka Hastings and Peter Cresswell. Disulfide reduction in the endocytic pathway: immunological functions of gamma-interferon-inducible lysosomal thiol reductase. Antioxidants & redox signaling, 15 3:657-68, Aug 2011. URL: https://doi.org/10.1089/ars.2010.3684, doi:10.1089/ars.2010.3684. This article has 119 citations and is from a domain leading peer-reviewed journal.
(west2013expandingrolesfor pages 7-10): Laura Ciaccia West and Peter Cresswell. Expanding roles for gilt in immunity. Current opinion in immunology, 25 1:103-8, Feb 2013. URL: https://doi.org/10.1016/j.coi.2012.11.006, doi:10.1016/j.coi.2012.11.006. This article has 92 citations and is from a peer-reviewed journal.
(macy2022roleofgilt pages 17-19): A Macy. Role of gilt in melanoma cells on regulating in vivo tumor growth. Unknown journal, 2022.
(west2013expandingrolesfor pages 4-6): Laura Ciaccia West and Peter Cresswell. Expanding roles for gilt in immunity. Current opinion in immunology, 25 1:103-8, Feb 2013. URL: https://doi.org/10.1016/j.coi.2012.11.006, doi:10.1016/j.coi.2012.11.006. This article has 92 citations and is from a peer-reviewed journal.
(west2013expandingrolesfor pages 6-7): Laura Ciaccia West and Peter Cresswell. Expanding roles for gilt in immunity. Current opinion in immunology, 25 1:103-8, Feb 2013. URL: https://doi.org/10.1016/j.coi.2012.11.006, doi:10.1016/j.coi.2012.11.006. This article has 92 citations and is from a peer-reviewed journal.
(macy2022roleofgilt pages 15-17): A Macy. Role of gilt in melanoma cells on regulating in vivo tumor growth. Unknown journal, 2022.
(hastings2011disulfidereductionin pages 8-9): Karen Taraszka Hastings and Peter Cresswell. Disulfide reduction in the endocytic pathway: immunological functions of gamma-interferon-inducible lysosomal thiol reductase. Antioxidants & redox signaling, 15 3:657-68, Aug 2011. URL: https://doi.org/10.1089/ars.2010.3684, doi:10.1089/ars.2010.3684. This article has 119 citations and is from a domain leading peer-reviewed journal.

Citations

hastings2011disulfidereductionin pages 8-9
macy2022roleofgilt pages 17-19
west2013expandingrolesfor pages 4-6
hastings2006functionalrequirementsfor pages 1-2
hastings2011disulfidereductionin pages 1-2
west2013expandingrolesfor pages 7-10
west2013expandingrolesfor pages 6-7
macy2022roleofgilt pages 15-17
https://doi.org/10.4049/jimmunol.177.12.8569
https://doi.org/10.1089/ars.2010.3684
https://doi.org/10.1016/j.coi.2012.11.006
https://doi.org/10.4049/jimmunol.177.12.8569,
https://doi.org/10.1089/ars.2010.3684,
https://doi.org/10.1016/j.coi.2012.11.006,

📄 View Raw YAML

id: P13284
gene_symbol: IFI30
aliases:
  - GILT
  - IP30
product_type: PROTEIN
status: COMPLETE
taxon:
  id: NCBITaxon:9606
  label: Homo sapiens
description: >-
  IFI30 encodes GILT (gamma-interferon-inducible lysosomal thiol reductase), the primary
  lysosomal thiol reductase responsible for reducing disulfide bonds in the endocytic
  pathway.
  GILT contains a thioredoxin-like CXXC active site motif (Cys-72 and Cys-75 in human)
  essential
  for its catalytic activity. The protein is synthesized as a ~35 kDa precursor with
  mannose-6-phosphate
  targeting signals, enabling delivery to lysosomes where it is processed to a ~28
  kDa mature form.
  GILT functions optimally at acidic pH (pH 4-5) and facilitates MHC class II antigen
  processing
  by reducing disulfide bonds in internalized antigens, enabling their unfolding and
  subsequent
  proteolytic processing. GILT is constitutively expressed in professional antigen-presenting
  cells
  (macrophages, dendritic cells, B cells) and is inducible by IFN-gamma in other cell
  types via
  STAT1 signaling (CIITA-independent). The protein can also form disulfide-linked
  dimers that
  retain enzymatic activity. Beyond its role in MHC class II antigen presentation,
  GILT also
  facilitates MHC class I cross-presentation of exogenous antigens containing disulfide
  bonds.
existing_annotations:
  - term:
      id: GO:0016667
      label: oxidoreductase activity, acting on a sulfur group of donors
    evidence_type: IBA
    original_reference_id: GO_REF:0000033
    review:
      summary: >-
        GILT is established as a lysosomal thiol reductase with a thioredoxin-like
        CXXC active
        site that catalyzes disulfide bond reduction. This IBA annotation is well-supported
        by phylogenetic evidence and experimental data across species.
      action: ACCEPT
      reason: >-
        This annotation accurately captures the core molecular function of GILT. The
        enzyme
        reduces disulfide bonds in the endolysosomal pathway using its CXXC active
        site motif.
        PMID:10639150 demonstrated the thiol reductase activity experimentally. PMID:17142755
        confirmed that the thiol reductase activity of GILT is its essential function
        in MHC
        class II-restricted Ag processing. The IBA annotation based on phylogenetic
        inference
        is consistent with this experimental evidence.
      supported_by:
        - reference_id: PMID:10639150
          supporting_text: >-
            We describe here a lysosomal thiol reductase optimally active at low pH
            and
            capable of catalyzing disulfide bond reduction both in vivo and in vitro.
            The active site, determined by mutagenesis, consists of a pair of cysteine
            residues separated by two amino acids, similar to other enzymes of the
            thioredoxin family.
        - reference_id: PMID:17142755
          supporting_text: >-
            These studies demonstrate that the thiol reductase activity of GILT is
            its
            essential function in MHC class II-restricted Ag processing.
        - reference_id: file:human/IFI30/IFI30-deep-research-falcon.md
          supporting_text: >-
            GILT is a lysosomal thiol reductase that enzymatically reduces disulfide
            bonds of endocytosed proteins, facilitating antigen processing; described
            as the primary/only known reductase in the endocytic/lysosomal compartment.
  - term:
      id: GO:0005764
      label: lysosome
    evidence_type: IBA
    original_reference_id: GO_REF:0000033
    review:
      summary: >-
        GILT localizes to lysosomes via mannose-6-phosphate receptor-mediated trafficking.
        This is a core localization supported by multiple experimental studies.
      action: ACCEPT
      reason: >-
        Lysosomal localization is a fundamental aspect of GILT function, enabling
        its
        activity at the acidic pH optimal for disulfide reduction. PMID:10639150 demonstrated
        mannose 6-phosphate receptor-mediated delivery. PMID:3136170 showed punctate
        fluorescence pattern in monocytes consistent with a vesicular subcellular
        location.
        The IBA annotation is well-supported.
      supported_by:
        - reference_id: PMID:10639150
          supporting_text: >-
            After delivery into the endosomal/lysosomal system by the mannose 6-phosphate
            receptor, N- and C-terminal prosequences are removed.
        - reference_id: PMID:3136170
          supporting_text: >-
            Indirect immunofluorescence microscopy reveals a punctate fluorescence
            pattern
            in monocytes consistent with a vesicular subcellular location.
        - reference_id: file:human/IFI30/IFI30-deep-research-falcon.md
          supporting_text: >-
            Localizes to the endocytic/MHC class II loading compartments (late endosomes/lysosomes)
            and shows maximal activity at acidic endolysosomal pH.
  - term:
      id: GO:0002376
      label: immune system process
    evidence_type: IEA
    original_reference_id: GO_REF:0000043
    review:
      summary: >-
        This is a very broad GO term derived from UniProt keyword mapping. While GILT
        does
        function in immunity, a more specific annotation (MHC class II antigen processing)
        already exists and is more informative.
      action: MARK_AS_OVER_ANNOTATED
      reason: >-
        The term "immune system process" (GO:0002376) is too general and uninformative.
        GILT's specific immune function is in antigen processing and presentation,
        which
        is already captured by the more specific annotations to GO:0019886 (MHC class
        II
        antigen presentation) and GO:0042590 (MHC class I cross-presentation). The
        automated IEA from UniProt keyword mapping is technically correct but redundant
        with more specific annotations that better characterize GILT's role.
      supported_by:
        - reference_id: PMID:10639150
          supporting_text: >-
            The enzyme is expressed constitutively in antigen-presenting cells and
            induced
            by IFN-gamma in other cell types, suggesting a potentially important role
            in
            antigen processing.
  - term:
      id: GO:0005576
      label: extracellular region
    evidence_type: IEA
    original_reference_id: GO_REF:0000044
    review:
      summary: >-
        GILT can be secreted as a disulfide-linked dimer, particularly by activated
        macrophages.
        This is a secondary localization, not the primary site of function.
      action: KEEP_AS_NON_CORE
      reason: >-
        While GILT is primarily a lysosomal enzyme, the precursor form can be secreted
        as
        a disulfide-linked dimer. PMID:3136170 demonstrated that IP-30 is either secreted
        or converted intracellularly. The deep research notes that a minor disulfide-linked
        dimeric precursor can be secreted by activated macrophages and retains activity.
        However, the primary functional site is the lysosome, so this should be marked
        as
        non-core.
      supported_by:
        - reference_id: PMID:3136170
          supporting_text: >-
            a 30-kDa polypeptide (referred to as IP-30) is either secreted or converted
            intracellularly into a 25-kDa protein
        - reference_id: file:human/IFI30/IFI30-deep-research-falcon.md
          supporting_text: >-
            A minor disulfide-linked dimeric precursor can be secreted by activated
            macrophages and retains activity
  - term:
      id: GO:0005764
      label: lysosome
    evidence_type: IEA
    original_reference_id: GO_REF:0000120
    review:
      summary: >-
        Duplicate annotation with IBA and IDA evidence. Lysosomal localization is
        well-supported and this IEA is consistent with experimental evidence.
      action: ACCEPT
      reason: >-
        This IEA annotation is consistent with the IBA and IDA annotations for the
        same
        term. Duplicates with different evidence codes are acceptable in GO annotation
        as they represent independent lines of evidence. The combined automated method
        (GO_REF:0000120) correctly predicts lysosomal localization based on ortholog
        data (mouse GILT) and UniProt subcellular location vocabulary.
      additional_reference_ids:
        - PMID:10639150
      supported_by:
        - reference_id: PMID:10639150
          supporting_text: 'Enzymatic reduction of disulfide bonds in lysosomes: characterization
            of a gamma-interferon-inducible lysosomal thiol reductase (GILT).'
  - term:
      id: GO:0016491
      label: oxidoreductase activity
    evidence_type: IEA
    original_reference_id: GO_REF:0000043
    review:
      summary: >-
        This is a parent term of the more specific GO:0016667 annotation. While correct,
        it is redundant with the more specific child term.
      action: ACCEPT
      reason: >-
        This IEA annotation from UniProt keyword mapping is technically correct -
        GILT
        is an oxidoreductase. While GO:0016667 (oxidoreductase activity, acting on
        a
        sulfur group of donors) is more specific and informative, having the broader
        parent term from IEA is acceptable as it represents an independent inference
        pathway. The annotation is not wrong, just less specific than the experimental
        annotations.
      supported_by:
        - reference_id: PMID:10639150
          supporting_text: >-
            We describe here a lysosomal thiol reductase optimally active at low pH
            and
            capable of catalyzing disulfide bond reduction both in vivo and in vitro.
  - term:
      id: GO:0016671
      label: oxidoreductase activity, acting on a sulfur group of donors,
        disulfide as acceptor
    evidence_type: IEA
    original_reference_id: GO_REF:0000002
    review:
      summary: >-
        This InterPro-based annotation is highly specific and accurately describes
        GILT's
        enzymatic function - reducing disulfide bonds using its thioredoxin-like active
        site.
      action: ACCEPT
      reason: >-
        GO:0016671 is a child of GO:0016667 and specifies that the acceptor is a disulfide
        bond, which is precisely what GILT does. This is the most specific MF term
        applicable
        to GILT's catalytic activity. The InterPro domain (IPR004911 - Interferon-induced_GILT)
        correctly predicts this function. PMID:10639150 demonstrated experimentally
        that
        GILT reduces disulfide bonds in protein substrates.
      supported_by:
        - reference_id: PMID:10639150
          supporting_text: >-
            Proteins internalized into the endocytic pathway are usually degraded.
            Efficient
            proteolysis requires denaturation, induced by acidic conditions within
            lysosomes, and reduction of inter- and intrachain disulfide bonds.
  - term:
      id: GO:0005515
      label: protein binding
    evidence_type: IPI
    original_reference_id: PMID:25416956
    review:
      summary: >-
        High-throughput interactome study detected GILT interactions with NOTCH2NLA
        and KRTAP4-12. These are from systematic Y2H screening but lack functional
        context.
      action: REMOVE
      reason: >-
        The term "protein binding" (GO:0005515) is uninformative and does not add
        value
        to GILT's functional annotation. PMID:25416956 is a large-scale proteome-wide
        interactome mapping study that used Y2H to detect binary protein-protein
        interactions. The interactions with NOTCH2NLA and KRTAP4-12 detected in this
        screen lack biological context and validation. These interactions do not inform
        us about GILT's function. Generic "protein binding" annotations from high-throughput
        screens without functional validation should be removed as they do not meet
        quality standards for informative annotations.
      supported_by:
        - reference_id: PMID:25416956
          supporting_text: A proteome-scale map of the human interactome
            network.
  - term:
      id: GO:0005515
      label: protein binding
    evidence_type: IPI
    original_reference_id: PMID:32296183
    review:
      summary: >-
        HuRI reference interactome study detected GILT interaction with TGM1 (transglutaminase
        1).
        This is another high-throughput Y2H finding without functional validation.
      action: REMOVE
      reason: >-
        PMID:32296183 is the HuRI reference map of the human binary protein interactome,
        presenting protein-protein interactions from systematic Y2H screening.
        The detected interaction between GILT and TGM1 lacks functional validation
        and biological context. TGM1 is a keratinocyte transglutaminase involved in
        epidermal
        differentiation, and there is no obvious functional connection to GILT's role
        in
        antigen processing. Generic "protein binding" annotations from these high-throughput
        screens are uninformative and should be removed. If a more specific binding
        function
        were characterized, that would be informative, but "protein binding" alone
        provides
        no functional insight.
      supported_by:
        - reference_id: PMID:32296183
          supporting_text: Apr 8. A reference map of the human binary protein
            interactome.
  - term:
      id: GO:0042590
      label: antigen processing and presentation of exogenous peptide antigen
        via MHC class I
    evidence_type: IEA
    original_reference_id: GO_REF:0000107
    review:
      summary: >-
        GILT facilitates MHC class I cross-presentation by reducing disulfide bonds
        in
        exogenous antigens. This annotation is transferred from mouse ortholog evidence.
      action: ACCEPT
      reason: >-
        GILT's role in cross-presentation is documented in the literature. The deep
        research document notes that reduction by GILT can enhance transfer of endocytosed
        disulfide-containing antigens into the cytosol for class I cross-presentation.
        The UniProt function annotation states GILT also facilitates MHC class I-restricted
        recognition of exogenous antigens containing disulfide bonds. The IEA from
        Ensembl
        Compara ortholog transfer is supported by this biological understanding.
      supported_by:
        - reference_id: file:human/IFI30/IFI30-deep-research-falcon.md
          supporting_text: >-
            Reduction by GILT can enhance transfer of endocytosed disulfide-containing
            antigens into the cytosol for class I cross-presentation in certain settings.
  - term:
      id: GO:0016671
      label: oxidoreductase activity, acting on a sulfur group of donors,
        disulfide as acceptor
    evidence_type: IMP
    original_reference_id: PMID:10639150
    review:
      summary: >-
        Direct experimental demonstration of GILT's disulfide reductase activity using
        mutant phenotype analysis of the CXXC active site cysteines.
      action: ACCEPT
      reason: >-
        PMID:10639150 is the seminal paper characterizing GILT's enzymatic function.
        The IMP (Inferred from Mutant Phenotype) evidence code is appropriate because
        the authors demonstrated that mutation of either Cys-72 or Cys-75 in the CXXC
        motif abolishes reductase activity. The abstract states the active site,
        determined by mutagenesis, consists of a pair of cysteine residues separated
        by two amino acids. This is strong experimental evidence for GO:0016671.
      supported_by:
        - reference_id: PMID:10639150
          supporting_text: >-
            The active site, determined by mutagenesis, consists of a pair of cysteine
            residues separated by two amino acids, similar to other enzymes of the
            thioredoxin family.
  - term:
      id: GO:0019886
      label: antigen processing and presentation of exogenous peptide antigen
        via MHC class II
    evidence_type: TAS
    original_reference_id: Reactome:R-HSA-2132295
    review:
      summary: >-
        GILT's role in MHC class II antigen processing is its primary biological function.
        Reactome pathway annotation is well-supported by primary literature.
      action: ACCEPT
      reason: >-
        This is a core function of GILT. The Reactome pathway R-HSA-2132295 describes
        MHC class II antigen presentation, within which GILT functions to reduce
        disulfide bonds in antigens to enable their processing. PMID:17142755 directly
        demonstrated that thiol reductase activity of GILT is its essential function
        in MHC class II-restricted Ag processing using GILT-deficient cell lines
        reconstituted with wild-type and mutant GILT. The deep research confirms GILT
        is the principal endocytic thiol reductase governing disulfide reduction in
        antigen processing.
      supported_by:
        - reference_id: PMID:17142755
          supporting_text: >-
            These studies demonstrate that the thiol reductase activity of GILT is
            its
            essential function in MHC class II-restricted Ag processing.
        - reference_id: Reactome:R-HSA-2213240
          supporting_text: >-
            The lysosomal thiol reductase gamma-IFN-inducible lysosomal thiol reductase
            (GILT) has been shown to facilitate MHC class II-restricted antigen (Ag)
            processing by breaking disulphide bonds.
  - term:
      id: GO:0016667
      label: oxidoreductase activity, acting on a sulfur group of donors
    evidence_type: EXP
    original_reference_id: PMID:10639150
    review:
      summary: >-
        Direct experimental evidence from the original characterization of GILT's
        enzymatic activity demonstrating its thiol reductase function.
      action: ACCEPT
      reason: >-
        PMID:10639150 provided the first comprehensive characterization of GILT as
        a
        lysosomal thiol reductase. The paper demonstrated catalytic activity both
        in vivo and in vitro, showing optimal activity at acidic pH and identifying
        the CXXC active site through mutagenesis. This is strong primary experimental
        evidence for the molecular function annotation.
      supported_by:
        - reference_id: PMID:10639150
          supporting_text: >-
            We describe here a lysosomal thiol reductase optimally active at low pH
            and
            capable of catalyzing disulfide bond reduction both in vivo and in vitro.
  - term:
      id: GO:0016667
      label: oxidoreductase activity, acting on a sulfur group of donors
    evidence_type: EXP
    original_reference_id: PMID:17142755
    review:
      summary: >-
        Follow-up experimental study confirming GILT's thiol reductase activity is
        essential for its function in antigen processing.
      action: ACCEPT
      reason: >-
        PMID:17142755 extended the findings of PMID:10639150 by demonstrating the
        functional requirements for GILT in MHC class II antigen processing. The
        study showed that mutation of either active site cysteine (Cys46 or Cys49
        in mouse, corresponding to Cys72/75 in human) abrogated both reductase
        activity and antigen processing function. This provides additional
        experimental support for the GO:0016667 annotation.
      supported_by:
        - reference_id: PMID:17142755
          supporting_text: >-
            Mutation of either Cys(46) or Cys(49) abrogated MHC class II processing
            of a GILT-dependent HEL epitope.
  - term:
      id: GO:0043202
      label: lysosomal lumen
    evidence_type: TAS
    original_reference_id: Reactome:R-HSA-1031716
    review:
      summary: >-
        GILT is localized to the lysosomal lumen where it functions at acidic pH.
        This Reactome annotation provides more specific localization than "lysosome."
      action: ACCEPT
      reason: >-
        GO:0043202 (lysosomal lumen) is more specific than GO:0005764 (lysosome) and
        accurately describes where GILT functions. As a soluble glycoprotein delivered
        via the mannose-6-phosphate pathway, the mature form of GILT resides in the
        lysosomal lumen where it reduces disulfide bonds in internalized antigens.
        Reactome pathway R-HSA-1031716 (Expression of IFNG-stimulated genes) includes
        GILT as an IFN-gamma inducible protein localized to this compartment.
      supported_by:
        - reference_id: PMID:10639150
          supporting_text: >-
            The enzyme is a soluble glycoprotein that is synthesized as a precursor.
            After delivery into the endosomal/lysosomal system by the mannose 6-phosphate
            receptor, N- and C-terminal prosequences are removed.
  - term:
      id: GO:0043202
      label: lysosomal lumen
    evidence_type: TAS
    original_reference_id: Reactome:R-HSA-2213240
    review:
      summary: >-
        Duplicate Reactome annotation for lysosomal lumen localization from the
        pathway specifically describing GILT's function in disulfide reduction.
      action: ACCEPT
      reason: >-
        Reactome pathway R-HSA-2213240 (Reduction of disulphide bonds in MHC II antigens)
        specifically describes GILT's function and localization. The pathway summary
        states The lysosomal thiol reductase GILT has been shown to facilitate MHC
        class II-restricted antigen processing by breaking disulphide bonds. GILT
        is
        constitutively expressed in APCs. The reduction of disulphide bonds by mature
        GILT is optimal at acidic pH. This confirms lysosomal lumen localization.
      supported_by:
        - reference_id: Reactome:R-HSA-2213240
          supporting_text: >-
            The lysosomal thiol reductase gamma-IFN-inducible lysosomal thiol reductase
            (GILT) has been shown to facilitate MHC class II-restricted antigen (Ag)
            processing by breaking disulphide bonds. GILT is constitutively expressed
            in APCs. The reduction of disulphide bonds by mature GILT is optimal at
            acidic pH
  - term:
      id: GO:0042590
      label: antigen processing and presentation of exogenous peptide antigen
        via MHC class I
    evidence_type: ISS
    original_reference_id: GO_REF:0000024
    review:
      summary: >-
        GILT facilitates cross-presentation to MHC class I based on sequence similarity
        to mouse ortholog with demonstrated function.
      action: ACCEPT
      reason: >-
        The ISS (Inferred from Sequence Similarity) annotation is based on manual
        curator
        judgment of sequence similarity to mouse GILT (UniProtKB:Q9ESY9), which has
        demonstrated function in cross-presentation. UniProt notes that GILT also
        facilitates MHC class I-restricted recognition of exogenous antigens containing
        disulfide bonds by CD8+ T-cells or crosspresentation (By similarity). This
        functional inference is reasonable given the high conservation between human
        and mouse GILT and the shared domain architecture.
      additional_reference_ids:
        - UniProtKB:Q9ESY9
  - term:
      id: GO:0005764
      label: lysosome
    evidence_type: IDA
    original_reference_id: PMID:10639150
    review:
      summary: >-
        Direct experimental demonstration of GILT lysosomal localization via immunofluorescence
        and mannose-6-phosphate trafficking studies.
      action: ACCEPT
      reason: >-
        PMID:10639150 directly demonstrated lysosomal localization of GILT. The paper
        showed that GILT is delivered to lysosomes via the mannose-6-phosphate receptor
        pathway, a hallmark of lysosomal protein targeting. The precursor is processed
        to the mature form upon arrival in the endosomal/lysosomal system. This IDA
        evidence is the strongest experimental support for lysosomal localization.
      supported_by:
        - reference_id: PMID:10639150
          supporting_text: >-
            After delivery into the endosomal/lysosomal system by the mannose 6-phosphate
            receptor, N- and C-terminal prosequences are removed.
  - term:
      id: GO:0005576
      label: extracellular region
    evidence_type: TAS
    original_reference_id: PMID:3136170
    review:
      summary: >-
        Original characterization showed GILT (IP-30) can be secreted, forming extracellular
        disulfide-linked dimers.
      action: KEEP_AS_NON_CORE
      reason: >-
        PMID:3136170 demonstrated that the 30-kDa precursor (IP-30) can be secreted
        and forms extracellular dimers. While this is a valid localization, the
        primary functional site of GILT is the lysosome. Secretion appears to be a
        secondary phenomenon, particularly in activated macrophages during inflammation.
      supported_by:
        - reference_id: PMID:3136170
          supporting_text: >-
            a 30-kDa polypeptide (referred to as IP-30) is either secreted or converted
            intracellularly into a 25-kDa protein
  - term:
      id: GO:0005764
      label: lysosome
    evidence_type: TAS
    original_reference_id: PMID:3136170
    review:
      summary: >-
        Original characterization suggested vesicular/lysosomal localization of IP-30
        based on immunofluorescence microscopy.
      action: ACCEPT
      reason: >-
        PMID:3136170 provided early evidence for lysosomal localization of GILT,
        showing punctate fluorescence pattern in monocytes consistent with a
        vesicular subcellular location. While this was suggestive rather than
        definitive, it was later confirmed by PMID:10639150 which demonstrated
        mannose-6-phosphate receptor-mediated delivery to lysosomes.
      supported_by:
        - reference_id: PMID:3136170
          supporting_text: >-
            Indirect immunofluorescence microscopy reveals a punctate fluorescence
            pattern in monocytes consistent with a vesicular subcellular location.
            These data are consistent with IP-30 being a novel IFN gamma-inducible
            protein which may be lysosomal in location.
  - term:
      id: GO:0015035
      label: protein-disulfide reductase activity
    evidence_type: IDA
    original_reference_id: PMID:10639150
    review:
      summary: >-
        GO:0015035 (protein-disulfide reductase activity) is more specific than GO:0016671
        because it specifies that the substrates are proteins. GILT specifically reduces
        disulfide bonds in endocytosed protein antigens to facilitate their unfolding
        and proteolytic processing.
      action: NEW
      reason: >-
        This term is a more precise annotation than GO:0016671 because GILT's established
        physiological substrates are proteins - endocytosed antigens that require
        disulfide
        bond reduction for processing. PMID:10639150 demonstrated that GILT catalyzes
        disulfide bond reduction in proteins both in vivo and in vitro. The study
        showed
        efficient denaturation and reduction of internalized proteins is required
        for
        proteolysis in the lysosome. The child terms of GO:0015035 specify cofactors
        (glutathione, NAD(P)H), but GILT uses free cysteine transported into the lysosome
        as its electron donor, so the parent term GO:0015035 is most appropriate.
      supported_by:
        - reference_id: PMID:10639150
          supporting_text: >-
            We describe here a lysosomal thiol reductase optimally active at low pH
            and
            capable of catalyzing disulfide bond reduction both in vivo and in vitro.
            The active site, determined by mutagenesis, consists of a pair of cysteine
            residues separated by two amino acids, similar to other enzymes of the
            thioredoxin family.
        - reference_id: PMID:17142755
          supporting_text: >-
            These studies demonstrate that the thiol reductase activity of GILT is
            its
            essential function in MHC class II-restricted Ag processing.
        - reference_id: file:human/IFI30/IFI30-deep-research-falcon.md
          supporting_text: >-
            GILT is a lysosomal thiol reductase that enzymatically reduces disulfide
            bonds of endocytosed proteins, facilitating antigen processing. Known
            GILT-dependent substrates include disulfide-rich model antigens (e.g.,
            hen egg lysozyme) and melanocyte differentiation antigens such as
            tyrosinase/TRP1.
references:
  - id: GO_REF:0000002
    title: Gene Ontology annotation through association of InterPro records with
      GO terms
    findings:
      - statement: The InterPro domain IPR004911 (Interferon-induced_GILT)
          correctly predicts the oxidoreductase activity acting on disulfide
          bonds.
  - id: GO_REF:0000024
    title: Manual transfer of experimentally-verified manual GO annotation data
      to orthologs by curator judgment of sequence similarity
    findings:
      - statement: Cross-presentation function inferred from mouse ortholog
          Q9ESY9.
  - id: GO_REF:0000033
    title: Annotation inferences using phylogenetic trees
    findings:
      - statement: IBA annotations for oxidoreductase activity and lysosomal
          localization are well-supported by the PANTHER phylogenetic tree and
          conserved function.
  - id: GO_REF:0000043
    title: Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword
      mapping
    findings:
      - statement: Keywords Oxidoreductase and Immunity correctly map to GO
          terms, though the immunity annotation is overly general.
  - id: GO_REF:0000044
    title: Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular
      Location vocabulary mapping, accompanied by conservative changes to GO
      terms applied by UniProt
    findings:
      - statement: Secreted and Lysosome keywords correctly predict
          extracellular and lysosomal localization.
  - id: GO_REF:0000107
    title: Automatic transfer of experimentally verified manual GO annotation
      data to orthologs using Ensembl Compara
    findings:
      - statement: Cross-presentation function transferred from mouse ortholog.
  - id: GO_REF:0000120
    title: Combined Automated Annotation using Multiple IEA Methods
    findings:
      - statement: Lysosomal localization correctly predicted from multiple
          sources.
  - id: PMID:10639150
    title: 'Enzymatic reduction of disulfide bonds in lysosomes: characterization
      of a gamma-interferon-inducible lysosomal thiol reductase (GILT).'
    findings:
      - statement: First comprehensive characterization of GILT enzymatic
          function.
        supporting_text: >-
          We describe here a lysosomal thiol reductase optimally active at low pH
          and
          capable of catalyzing disulfide bond reduction both in vivo and in vitro.
      - statement: Demonstrated thiol reductase activity optimal at acidic pH.
        supporting_text: >-
          We describe here a lysosomal thiol reductase optimally active at low pH
      - statement: Identified CXXC active site through mutagenesis.
        supporting_text: >-
          The active site, determined by mutagenesis, consists of a pair of cysteine
          residues separated by two amino acids, similar to other enzymes of the
          thioredoxin family.
      - statement: Showed mannose-6-phosphate receptor-mediated lysosomal
          targeting.
        supporting_text: >-
          After delivery into the endosomal/lysosomal system by the mannose 6-phosphate
          receptor, N- and C-terminal prosequences are removed.
      - statement: Demonstrated processing from 35 kDa precursor to mature form.
        supporting_text: >-
          The enzyme is a soluble glycoprotein that is synthesized as a precursor.
  - id: PMID:17142755
    title: Functional requirements for the lysosomal thiol reductase GILT in MHC
      class II-restricted antigen processing.
    findings:
      - statement: Demonstrated that GILT thiol reductase activity is essential
          for MHC class II antigen processing.
        supporting_text: >-
          These studies demonstrate that the thiol reductase activity of GILT is its
          essential function in MHC class II-restricted Ag processing.
      - statement: Showed that active site cysteine mutations abolish antigen
          processing function.
        supporting_text: >-
          Mutation of either Cys(46) or Cys(49) abrogated MHC class II processing
          of a GILT-dependent HEL epitope.
      - statement: Established functional link between enzymatic activity and
          immune function.
        supporting_text: >-
          These studies demonstrate that the thiol reductase activity of GILT is its
          essential function in MHC class II-restricted Ag processing.
  - id: PMID:25416956
    title: A proteome-scale map of the human interactome network.
    findings:
      - statement: High-throughput Y2H screen detecting binary protein
          interactions including GILT interactions lacking functional
          validation.
  - id: PMID:3136170
    title: Molecular and biochemical characterization of a novel
      gamma-interferon-inducible protein.
    findings:
      - statement: Original characterization of IP-30 (GILT) as
          IFN-gamma-inducible protein.
        supporting_text: >-
          A cDNA clone has been isolated from mRNA derived from the monocytic cell
          line
          U937, which detects an mRNA that is present and inducible by gamma-interferon
      - statement: Demonstrated secretion and intracellular processing.
        supporting_text: >-
          a 30-kDa polypeptide (referred to as IP-30) is either secreted or converted
          intracellularly into a 25-kDa protein
      - statement: Showed vesicular localization consistent with lysosomes.
        supporting_text: >-
          Indirect immunofluorescence microscopy reveals a punctate fluorescence pattern
          in monocytes consistent with a vesicular subcellular location.
      - statement: Identified disulfide-linked dimeric forms.
        supporting_text: >-
          the extracellular form is involved in both intrachain and interchain disulfide
          bonding.
  - id: PMID:32296183
    title: A reference map of the human binary protein interactome.
    findings:
      - statement: HuRI reference interactome with protein-protein interactions
          detected by Y2H, including GILT-TGM1 interaction without functional
          validation.
  - id: Reactome:R-HSA-1031716
    title: Expression of IFNG-stimulated genes
    findings:
      - statement: GILT is an IFN-gamma-inducible gene.
  - id: Reactome:R-HSA-2132295
    title: MHC class II antigen presentation
    findings:
      - statement: GILT functions in the MHC class II antigen presentation
          pathway.
  - id: Reactome:R-HSA-2213240
    title: Reduction of disulphide bonds in MHC II antigens
    findings:
      - statement: GILT specifically catalyzes disulfide bond reduction in MHC
          II antigens.
        supporting_text: >-
          The lysosomal thiol reductase gamma-IFN-inducible lysosomal thiol reductase
          (GILT) has been shown to facilitate MHC class II-restricted antigen (Ag)
          processing by breaking disulphide bonds.
      - statement: Optimal activity at acidic pH in lysosomes.
        supporting_text: >-
          The reduction of disulphide bonds by mature GILT is optimal at acidic pH
core_functions:
  - description: >-
      GILT is a lysosomal thiol reductase that catalyzes the reduction of disulfide
      bonds
      in proteins internalized into the endocytic pathway. It contains a thioredoxin-like
      CXXC active site motif (Cys-72 and Cys-75) essential for catalytic activity.
      The
      enzyme shows optimal activity at acidic pH (pH 4-5), consistent with its lysosomal
      localization.
    molecular_function:
      id: GO:0015035
      label: protein-disulfide reductase activity
    locations:
      - id: GO:0043202
        label: lysosomal lumen
    directly_involved_in:
      - id: GO:0019886
        label: antigen processing and presentation of exogenous peptide antigen
          via MHC class II
proposed_new_terms: []
suggested_questions:
  - question: What specific protein substrates beyond model antigens (HEL,
      tyrosinase) are reduced by GILT in physiological antigen processing?
  - question: What is the functional significance of the secreted GILT dimer
      form? Does it have extracellular reductase activity on specific targets?
  - question: How does GILT coordinate with other lysosomal proteases in the
      antigen processing pathway?
suggested_experiments:
  - description: Quantitative proteomics to identify GILT substrates in the
      endolysosomal pathway using trapping mutant approaches.
    hypothesis: GILT has specific substrate preferences beyond model antigens.
  - description: Characterization of GILT's role in processing specific
      pathogen-derived antigens relevant to vaccine development.
    hypothesis: GILT-dependent antigen processing affects vaccine
      immunogenicity.
  - description: Investigation of GILT's role in tumor antigen processing and
      implications for cancer immunotherapy.
    hypothesis: GILT expression levels in tumors correlate with antigen
      presentation efficiency and immunotherapy response.

Gene Description

Existing Annotations Review

Core Functions

References

Suggested Questions for Experts

Suggested Experiments

Deep Research

Falcon

Citations

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