GUSB

Existing Annotations Review

GO Term	Evidence	Action	Reason
GO:0005576 extracellular region	IBA GO_REF:0000033	KEEP AS NON CORE	Summary: Phylogenetic (IBA) annotation to extracellular region. Beta-glucuronidase is primarily a lysosomal hydrolase, but it is secreted and detected in the extracellular space/exosomes, so the location is not wrong; it is peripheral to the core lysosomal catabolic function. Reason: GUSB is fundamentally a lysosomal enzyme; extracellular presence reflects secretion, granule exocytosis and exosomal release rather than its principal site of action. Retained as non-core.
GO:0004566 beta-glucuronidase activity	IBA GO_REF:0000033	ACCEPT	Summary: Phylogenetic (IBA) assignment of beta-glucuronidase activity (EC 3.2.1.31), the defining molecular function of GUSB. Supported across evidence types and by the catalytic reaction annotated in UniProt. Reason: This is the core molecular function. GUSB hydrolyses terminal non-reducing beta-D-glucuronic acid residues; the reaction is directly documented, and enzymatic activity was measured on human enzyme. Supporting Evidence: file:human/GUSB/GUSB-uniprot.txt Reaction=a beta-D-glucuronoside + H2O = D-glucuronate + an alcohol; PMID:3468507 the cDNA sequence for human placental beta-glucuronidase (beta-D-glucuronoside glucuronosohydrolase, EC 3.2.1.31)
GO:0030214 hyaluronan catabolic process	IBA GO_REF:0000033	KEEP AS NON CORE	Summary: Phylogenetic (IBA) annotation for hyaluronan catabolism. Purified human beta-glucuronidase is active on hyaluronic acid oligosaccharides, consistent with an exolytic role in stepwise hyaluronan degradation. Reason: GUSB contributes to hyaluronan turnover as one of the terminal exoglycosidases, but hyaluronan degradation is one of several GAG substrates; kept as a specific non-core catabolic process under the general glycosaminoglycan catabolic role. Supporting Evidence: PMID:7354065 Both forms of these enzymes are active on 4-methyl umbelliferyl-beta-D-glucuronide and on the hexasaccharides of chondroitin-6-SO4, chondroitin, and hyaluronic acid
GO:0030200 heparan sulfate proteoglycan catabolic process	IBA GO_REF:0000033	ACCEPT	Summary: Phylogenetic (IBA) annotation for heparan sulfate catabolism. GUSB removes terminal beta-D-glucuronic acid residues during the stepwise lysosomal degradation of heparan sulfate; deficiency causes glycosaminoglycan storage (MPS VII). Reason: Consistent with the enzyme's exolytic role in glycosaminoglycan degradation and with the lysosomal storage of undegraded GAGs on deficiency. A verified core catabolic process. Supporting Evidence: PMID:1465145 results from lysosomal storage of undegraded glycosaminoglycans in the spleen, liver, kidney, cornea, brain and skeletal system
GO:0030207 chondroitin sulfate proteoglycan catabolic process	IBA GO_REF:0000033	ACCEPT	Summary: Phylogenetic (IBA) annotation for chondroitin sulfate catabolism. Purified human beta-glucuronidase is active on chondroitin and chondroitin-6-sulfate oligosaccharides, supporting its role in exolytic chondroitin/dermatan sulfate degradation. Reason: Directly supported by measured enzymatic activity on chondroitin-6-SO4 and chondroitin oligosaccharides and by UniProt's degradation-of-dermatan-sulfate function. A verified core catabolic process. Supporting Evidence: PMID:7354065 Both forms of these enzymes are active on 4-methyl umbelliferyl-beta-D-glucuronide and on the hexasaccharides of chondroitin-6-SO4, chondroitin, and hyaluronic acid file:human/GUSB/GUSB-uniprot.txt FUNCTION: Plays an important role in the degradation of dermatan and
GO:0005102 signaling receptor binding	IBA GO_REF:0000033	MARK AS OVER ANNOTATED	Summary: Phylogenetic (IBA) annotation for signaling receptor binding. This is a bare protein-binding-type term that does not describe an informative molecular function of a lysosomal hydrolase; the underlying interaction is recognition of the enzyme's mannose-6-phosphate tag by the mannose-6-phosphate receptor, a trafficking event. Reason: "Signaling receptor binding" over-interprets the mannose-6-phosphate-receptor recognition that traffics GUSB to the lysosome; it does not represent a signaling function of GUSB. Marked as over-annotation per curation guidance to avoid uninformative binding terms.
GO:0030246 carbohydrate binding	IBA GO_REF:0000033	MARK AS OVER ANNOTATED	Summary: Phylogenetic (IBA) annotation for carbohydrate binding. Substrate (glycosaminoglycan) binding is intrinsic to the catalytic activity and is captured more informatively by the beta-glucuronidase activity term. Reason: Carbohydrate binding here reflects substrate engagement by the active site and is subsumed by GO:0004566 beta-glucuronidase activity; as a standalone binding term it is an over-annotation.
GO:0004553 hydrolase activity, hydrolyzing O-glycosyl compounds	IEA GO_REF:0000002	ACCEPT	Summary: InterPro2GO (IEA) mapping to the parent O-glycosyl hydrolase term based on GH2 domain signatures. Correct but less specific than the beta-glucuronidase activity term. Reason: A correct, more general parent of GO:0004566. Acceptable as a broader IEA mapping; the specific activity is captured separately.
GO:0004566 beta-glucuronidase activity	IEA GO_REF:0000120	ACCEPT	Summary: Automated (IEA, ARBA/EC/RHEA) assignment of beta-glucuronidase activity from EC 3.2.1.31 and RHEA:17633. Consistent with the core molecular function. Reason: Correct EC/RHEA-based electronic mapping of the defining catalytic activity. Supporting Evidence: file:human/GUSB/GUSB-uniprot.txt Reaction=a beta-D-glucuronoside + H2O = D-glucuronate + an alcohol;
GO:0005764 lysosome	IEA GO_REF:0000044	ACCEPT	Summary: UniProt SubCell (IEA) mapping to lysosome, matching the annotated lysosomal subcellular location. This is the core site of action. Reason: GUSB is a lysosomal hydrolase; localisation to the lysosome is well established and central to its catabolic function. Supporting Evidence: file:human/GUSB/GUSB-uniprot.txt SUBCELLULAR LOCATION: Lysosome.
GO:0005975 carbohydrate metabolic process	IEA GO_REF:0000002	ACCEPT	Summary: InterPro2GO (IEA) mapping to the broad carbohydrate metabolic process term. Correct but general; the specific glycosaminoglycan catabolic processes are more informative. Reason: A correct high-level parent process. Acceptable as broader IEA context.
GO:0030214 hyaluronan catabolic process	IEA GO_REF:0000117	KEEP AS NON CORE	Summary: ARBA (IEA) annotation for hyaluronan catabolism, duplicating the IBA/IDA assignments. Supported by measured activity on hyaluronic acid oligosaccharides. Reason: Correct but one of several GAG substrate processes; kept as a specific non-core catabolic process. Supporting Evidence: PMID:7354065 Both forms of these enzymes are active on 4-methyl umbelliferyl-beta-D-glucuronide and on the hexasaccharides of chondroitin-6-SO4, chondroitin, and hyaluronic acid
GO:0004566 beta-glucuronidase activity	TAS Reactome:R-HSA-2318373	ACCEPT	Summary: Reactome (TAS) assertion of beta-glucuronidase activity in the context of hyaluronan/GAG degradation reactions. Consistent with the core molecular function. Reason: Reactome-curated pathway assertion of the defining catalytic activity.
GO:0004566 beta-glucuronidase activity	TAS Reactome:R-HSA-9036068	ACCEPT	Summary: Reactome (TAS) assertion of beta-glucuronidase activity (GlcA-beta1,3-GlcNAc hydrolysis reaction). Consistent with the core molecular function. Reason: Reactome-curated assertion of the defining catalytic activity in CS/HS degradation.
GO:0004566 beta-glucuronidase activity	TAS Reactome:R-HSA-9036070	ACCEPT	Summary: Reactome (TAS) assertion of beta-glucuronidase activity (CS/HS precursor hydrolysis). Consistent with the core molecular function. Reason: Reactome-curated assertion of the defining catalytic activity.
GO:0004566 beta-glucuronidase activity	IDA PMID:7354065 Multiple kinetic forms of beta-glucuronidase.	ACCEPT	Summary: Direct assay (IDA) of beta-glucuronidase activity: highly purified human placental beta-glucuronidase hydrolyses 4-methylumbelliferyl-beta-D-glucuronide and GAG-derived oligosaccharides. This is direct experimental support for the core molecular function. Reason: Experimental demonstration of catalytic activity of the human enzyme on both a synthetic beta-D-glucuronide substrate and physiological GAG oligosaccharides. Supporting Evidence: PMID:7354065 Both forms of these enzymes are active on 4-methyl umbelliferyl-beta-D-glucuronide and on the hexasaccharides of chondroitin-6-SO4, chondroitin, and hyaluronic acid
GO:0030214 hyaluronan catabolic process	IDA PMID:7354065 Multiple kinetic forms of beta-glucuronidase.	KEEP AS NON CORE	Summary: Direct assay (IDA) supporting a role in hyaluronan catabolism: purified human beta-glucuronidase acts on hyaluronic acid oligosaccharides, consistent with exolytic participation in hyaluronan degradation. Reason: Supported by measured activity on hyaluronic acid hexasaccharides; retained as a specific non-core catabolic process (one of several GAG substrates). Supporting Evidence: PMID:7354065 Both forms of these enzymes are active on 4-methyl umbelliferyl-beta-D-glucuronide and on the hexasaccharides of chondroitin-6-SO4, chondroitin, and hyaluronic acid
GO:0005576 extracellular region	TAS Reactome:R-HSA-6798751	KEEP AS NON CORE	Summary: Reactome (TAS) annotation of extracellular localisation via neutrophil azurophil granule exocytosis (degranulation). Real but peripheral to the core lysosomal role. Reason: Reflects secretion/degranulation of the lysosomal enzyme; peripheral to the core lysosomal catabolic function.
GO:0005576 extracellular region	TAS Reactome:R-HSA-6800434	KEEP AS NON CORE	Summary: Reactome (TAS) annotation of extracellular localisation via ficolin-1-rich granule exocytosis. Peripheral to the core lysosomal role. Reason: Reflects granule exocytosis of the enzyme; peripheral to core function.
GO:0035578 azurophil granule lumen	TAS Reactome:R-HSA-6798751	KEEP AS NON CORE	Summary: Reactome (TAS) localisation to the azurophil granule lumen of neutrophils, consistent with GUSB being stored in these lysosome-related granules and released on degranulation. Reason: Azurophil granules are lysosome-related organelles; localisation is plausible but cell-type-specific and peripheral to the core lysosomal catabolic role.
GO:1904813 ficolin-1-rich granule lumen	TAS Reactome:R-HSA-6800434	KEEP AS NON CORE	Summary: Reactome (TAS) localisation to the ficolin-1-rich granule lumen of neutrophils. Cell-type-specific storage location, peripheral to the core lysosomal role. Reason: Neutrophil granule localisation; peripheral to the core catabolic function.
GO:0005576 extracellular region	IDA PMID:25645918 Human neutrophils secrete bioactive paucimannosidic proteins...	KEEP AS NON CORE	Summary: IDA localisation to the extracellular region, from a study of proteins secreted from neutrophil azurophilic granules into pathogen-infected sputum. Consistent with secretion of the enzyme; peripheral to the core lysosomal role. Reason: Extracellular detection reflects granule secretion; peripheral to core function.
GO:0005102 signaling receptor binding	IPI PMID:20028034 Residues essential for plasminogen binding by the cation-ind...	MARK AS OVER ANNOTATED	Summary: IPI annotation (with UniProtKB:P08169, the cation-independent mannose-6-phosphate receptor). In this study human beta-glucuronidase was used as a mannose-6-phosphate ligand purified on a CI-MPR affinity column; the interaction is receptor recognition of the enzyme's M6P tag for lysosomal trafficking, not a signaling function. This is a bare, uninformative binding term for GUSB. Reason: The M6P-receptor interaction is a trafficking/recognition event, not signaling receptor engagement by GUSB; annotating GUSB with "signaling receptor binding" over-interprets it. Retained as over-annotation rather than removed (experimental IPI). Per curation guidance, bare binding terms are uninformative. Supporting Evidence: PMID:20028034 a carbohydrate moiety, mannose 6-phosphate (Man-6-P) found on N-linked glycans of lysosomal enzymes
GO:0019904 protein domain specific binding	IPI PMID:20028034 Residues essential for plasminogen binding by the cation-ind...	MARK AS OVER ANNOTATED	Summary: IPI annotation (with UniProtKB:P08169) for protein domain specific binding. Same underlying CI-MPR/M6P recognition as above; a bare, uninformative binding term for a lysosomal hydrolase. Reason: Captures the mannose-6-phosphate-receptor recognition of GUSB; uninformative as a standalone binding function. Retained as over-annotation rather than removed (experimental IPI). Supporting Evidence: PMID:20028034 a carbohydrate moiety, mannose 6-phosphate (Man-6-P) found on N-linked glycans of lysosomal enzymes
GO:0070062 extracellular exosome	HDA PMID:23533145 In-depth proteomic analyses of exosomes isolated from expres...	KEEP AS NON CORE	Summary: High-throughput proteomics (HDA) detection of GUSB in urinary/prostatic exosomes. Consistent with the secreted/exosomal presence of the enzyme; peripheral to core function. Reason: Exosomal detection is a peripheral localisation typical of many lysosomal/secreted proteins; not the core site of action.
GO:0016020 membrane	HDA PMID:19946888 Defining the membrane proteome of NK cells.	MARK AS OVER ANNOTATED	Summary: High-throughput proteomics (HDA) detection of GUSB in an NK-cell membrane-proteome fraction. GUSB is a soluble lumenal enzyme; membrane co-fractionation is likely association with membrane-bounded compartments rather than an integral membrane role. Reason: GUSB has no transmembrane domain and is a soluble lysosomal/secreted enzyme; the generic "membrane" term from a membrane-fraction proteomics screen over-interprets a co-purification. Retained as over-annotation.
GO:0070062 extracellular exosome	HDA PMID:19056867 Large-scale proteomics and phosphoproteomics of urinary exos...	KEEP AS NON CORE	Summary: High-throughput proteomics (HDA) detection of GUSB in urinary exosomes, duplicating the exosome localisation. Peripheral to core function. Reason: Exosomal detection; peripheral localisation, not the core site of action.
GO:0043202 lysosomal lumen	TAS Reactome:R-HSA-2318373	ACCEPT	Summary: Reactome (TAS) localisation to the lysosomal lumen, the core compartment where GUSB acts as a soluble exoglycosidase in GAG degradation. Reason: Lysosomal lumen is the core site of action for this soluble lysosomal hydrolase. Supporting Evidence: file:human/GUSB/GUSB-uniprot.txt SUBCELLULAR LOCATION: Lysosome.
GO:0043202 lysosomal lumen	TAS Reactome:R-HSA-9036068	ACCEPT	Summary: Reactome (TAS) localisation to the lysosomal lumen (CS/HS degradation context). Core compartment of action. Reason: Core lysosomal lumen localisation. Supporting Evidence: file:human/GUSB/GUSB-uniprot.txt SUBCELLULAR LOCATION: Lysosome.
GO:0043202 lysosomal lumen	TAS Reactome:R-HSA-9036070	ACCEPT	Summary: Reactome (TAS) localisation to the lysosomal lumen (CS/HS degradation context). Core compartment of action. Reason: Core lysosomal lumen localisation. Supporting Evidence: file:human/GUSB/GUSB-uniprot.txt SUBCELLULAR LOCATION: Lysosome.
GO:0043202 lysosomal lumen	TAS Reactome:R-HSA-1678854	ACCEPT	Summary: Reactome (TAS) localisation to the lysosomal lumen (GUSB tetramer hydrolyses CS/HS precursor). Core compartment of action. Reason: Core lysosomal lumen localisation. Supporting Evidence: file:human/GUSB/GUSB-uniprot.txt SUBCELLULAR LOCATION: Lysosome.
GO:0043202 lysosomal lumen	TAS Reactome:R-HSA-2162226	ACCEPT	Summary: Reactome (TAS) localisation to the lysosomal lumen (GUSB tetramer hydrolyzes GlcA-beta1,3-GlcNAc). Core compartment of action. Reason: Core lysosomal lumen localisation. Supporting Evidence: file:human/GUSB/GUSB-uniprot.txt SUBCELLULAR LOCATION: Lysosome.
GO:0043202 lysosomal lumen	TAS Reactome:R-HSA-2162227	ACCEPT	Summary: Reactome (TAS) localisation to the lysosomal lumen (GUSB tetramer hydrolyses (HA)2). Core compartment of action. Reason: Core lysosomal lumen localisation. Supporting Evidence: file:human/GUSB/GUSB-uniprot.txt SUBCELLULAR LOCATION: Lysosome.
GO:0004566 beta-glucuronidase activity	TAS PMID:3468507 Cloning, sequencing, and expression of cDNA for human beta-g...	ACCEPT	Summary: TAS annotation of beta-glucuronidase activity from the cDNA cloning/expression paper, which expressed catalytically active human beta-glucuronidase (EC 3.2.1.31) in COS cells. Supports the core molecular function. Reason: Author-stated activity of the human enzyme; the same paper reports functional expression of active beta-glucuronidase. Supporting Evidence: PMID:3468507 the cDNA sequence for human placental beta-glucuronidase (beta-D-glucuronoside glucuronosohydrolase, EC 3.2.1.31)
GO:0005975 carbohydrate metabolic process	TAS PMID:3468507 Cloning, sequencing, and expression of cDNA for human beta-g...	ACCEPT	Summary: TAS annotation to the broad carbohydrate metabolic process term from the cloning paper. Correct but general; more specific GAG catabolic processes better capture the role. Reason: Correct high-level process; acceptable as broader context.
GO:0006027 glycosaminoglycan catabolic process	TAS PMID:1465145 Reversal of pathology in murine mucopolysaccharidosis type V...	ACCEPT	Summary: TAS annotation to glycosaminoglycan catabolic process. Beta-glucuronidase deficiency causes lysosomal accumulation of undegraded glycosaminoglycans (Sly syndrome / MPS VII), directly establishing its role in GAG catabolism. Reason: This is the core biological process. Loss of GUSB blocks stepwise GAG degradation and leads to lysosomal GAG storage, as shown genetically in the MPS VII model. Supporting Evidence: PMID:1465145 An inherited deficiency of beta-glucuronidase in humans, mice and dogs causes mucopolysaccharidosis VII (Sly syndrome), a progressive degenerative disease PMID:1465145 results from lysosomal storage of undegraded glycosaminoglycans in the spleen, liver, kidney, cornea, brain and skeletal system

Gene Description

Existing Annotations Review

Core Functions

Lysosomal beta-glucuronidase (EC 3.2.1.31): hydrolyses terminal, non-reducing beta-D-glucuronic acid residues from glycosaminoglycans, functioning as an exolytic exoglycosidase in the stepwise lysosomal degradation of heparan sulfate, dermatan sulfate, chondroitin sulfate and hyaluronan.

References

📚 Additional Documentation

Notes

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