ARSL (arylsulfatase L, formerly ARSE) is a glycosylated sulfatase that acts in the Golgi lumen. It promotes removal of the 4-O-sulfate from chondroitin sulfate chains during proteoglycan maturation, linking glycan sulfation to cartilage and bone development. Its full physiological substrate range remains incompletely defined. Activity depends on a conserved catalytic cysteine that undergoes formylglycine maturation. ARSL also hydrolyzes artificial aryl-sulfate substrates. Pathogenic loss of function causes X-linked recessive chondrodysplasia punctata, with abnormal cartilage development and skeletal mineralization.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0001501 skeletal system development | TAS PMID:7720070 A cluster of sulfatase genes on Xp22.3: mutations in chondro... | ACCEPT | Summary: Accept the role of ARSL in cartilage and skeletal development. Reason: The original human genetic study connects loss of ARSL activity to CDPX. Recent human-enzyme rescue in rat chondrocytes and experiments on the medaka ortholog support a catalytic contribution through matrix glycan maturation. This is a review of the existing developmental assertion; the animal models are not human cartilage experiments. Supporting Evidence: PMID:7720070 Point mutations in one of these genes were identified in five patients with CDPX. |
| GO:0004065 arylsulfatase activity | EXP PMID:7720070 A cluster of sulfatase genes on Xp22.3: mutations in chondro... | KEEP AS NON CORE | Summary: Retain the experimentally established aryl-sulfate assay activity. Reason: PMID:7720070 reports heat-labile activity after human-gene expression in COS cells. The shipped UniProt record identifies the artificial substrate as 4-methylumbelliferyl sulfate. The phenol-sulfate reaction defined by GO:0004065 is real assay chemistry; it is not the definition of physiological chondroitin desulfation. Supporting Evidence: file:human/ARSL/ARSL-uniprot.txt substrate 4-methylumbelliferyl sulfate |
| GO:0004065 arylsulfatase activity | IBA GO_REF:0000033 | KEEP AS NON CORE | Summary: Retain the inherited aryl-sulfate activity as non-core. Reason: The PAINT assertion is consistent with target-specific activity. P51690 appearing among the source entities is expected when target experiments informed an ancestral assertion; it is not circular evidence. The tree and alignment were not independently reanalyzed, and there is no target-specific evidence challenging the placement. The non-core distinction concerns substrate physiology, not donor count. Propagation Review Root cause: NO FAILURE NON CORE Sources checked: PANTHER:PTN000819263 UNRESOLVED Preserved PAINT ancestral assertion; human ARSL assays independently corroborate the transferred activity. Node topology and alignment were not independently replayed. |
| GO:0004065 arylsulfatase activity | IDA PMID:9497243 Biochemical characterization of arylsulfatase E and function... | KEEP AS NON CORE | Summary: Retain human ARSL arylsulfatase activity measured in transfected cells. Reason: The original abstract reports the assay and loss of activity in four of five patient substitutions, with one variant behaving like wild type. This supports real catalytic activity on the tested substrate without identifying an endogenous aryl sulfate or implying that every patient variant lacks activity. Supporting Evidence: PMID:9497243 All four of the other mutations resulted in a complete lack of arylsulfatase activity |
| GO:0004065 arylsulfatase activity | IEA GO_REF:0000120 | KEEP AS NON CORE | Summary: Retain the EC/Rhea mapping for the supported aryl-sulfate reaction. Reason: RHEA:17261 and EC:3.1.6.1 in the shipped record specify aryl-sulfate hydrolysis. They describe the established artificial-substrate activity and do not establish chondroitin specificity. The mapping is retained at its original scope. Propagation Review Root cause: NO FAILURE NON CORE Sources checked: RHEA:17261 SUPPORTS TRANSFER The shipped UniProt catalytic reaction explicitly identifies an aryl sulfate yielding a phenol and sulfate. EC:3.1.6.1 SUPPORTS TRANSFER The matching enzyme class describes the same experimentally supported assay reaction, without assigning a glycan substrate. |
| GO:0004065 arylsulfatase activity | TAS PMID:9192838 Identification by shotgun sequencing, genomic organization, ... | KEEP AS NON CORE | Summary: Retain the source-reported ARSE activity despite the ARSF-focused title. Reason: The complete abstract explicitly recounts ARSE expression and activity and distinguishes its warfarin response from ARSF. The historical ARSE name refers to ARSL. The title does not demonstrate a paralog misattribution; this activity remains an assay property rather than the physiological glycan reaction. Supporting Evidence: PMID:9192838 Expression of the ARSE gene in COS cells resulted in a heat-labile arylsulfatase activity |
| GO:0005788 endoplasmic reticulum lumen | IEA GO_REF:0000117 | KEEP AS NON CORE | Summary: Retain ER-lumen localization during sulfatase maturation. Reason: ARSL enters the secretory pathway and is a substrate of sulfatase maturation. The inspected Reactome precursor and modified human ARSE/P51690 participants are both placed in the ER lumen. This supports a processing-stage location, while mature enzyme activity is associated with the Golgi. Golgi localization does not negate transient ER residence. The exact ARBA rule predicates were not inspected; this judgment is independently supported by the human participant model. |
| GO:0005788 endoplasmic reticulum lumen | TAS Reactome:R-HSA-1614362 | KEEP AS NON CORE | Summary: Retain the modeled ER-lumen precursor and maturation location. Reason: ARSL enters the secretory pathway and is a substrate of sulfatase maturation. The inspected Reactome precursor and modified human ARSE/P51690 participants are both placed in the ER lumen. This supports a processing-stage location, while mature enzyme activity is associated with the Golgi. Golgi localization does not negate transient ER residence. SUMF1 performs the oxidation; ARSL is the protein being matured, not the enzyme activating other sulfatases. |
| GO:0005794 Golgi apparatus | IDA GO_REF:0000052 | ACCEPT | Summary: Accept the Golgi localization supported by curated immunofluorescence. Reason: The current HPA gene-level Golgi assignment is Supported. HPA060518 has Supported ICC validation and Golgi staining in Hep-G2; the displayed A-549 and U2OS entries report no staining. These are inspected site annotations, not an independent image-pixel assessment, and the conclusion does not assume positive staining in all tested lines. |
| GO:0005794 Golgi apparatus | IDA PMID:9497243 Biochemical characterization of arylsulfatase E and function... | ACCEPT | Summary: Accept Golgi localization of mature human ARSL. Reason: PMID:9497243 directly reports Golgi localization of glycosylated human ARSE expressed in Cos7 cells. Recent localization and protease-protection experiments reinforce a luminal Golgi role; the original human expression system and later rat-cell context remain distinct. |
| GO:0005795 Golgi stack | IEA GO_REF:0000044 | ACCEPT | Summary: Accept the Golgi-stack location mapped from UniProt. Reason: The shipped SL-0135 assignment is anchored to the human ARSE localization study. It agrees with the mature Golgi location and the newer cellular localization experiments. This is a vocabulary mapping, not an additional independent localization experiment. Propagation Review Root cause: NO FAILURE CORE Sources checked: UniProtKB-SubCell:SL-0135 SUPPORTS TRANSFER Shipped UniProt explicitly records Golgi apparatus, Golgi stack with PMID:9497243; no unobserved antibody experiment is attributed to this mapping. |
| GO:0070062 extracellular exosome | HDA PMID:19056867 Large-scale proteomics and phosphoproteomics of urinary exos... | MARK AS OVER ANNOTATED | Summary: Detected in an extracellular-vesicle proteome, but the detection does not establish that this protein is an EV constituent. Reason: Golgi-resident arylsulfatase. Mainly resident in an intracellular compartment that MISEV2018 (PMID:30637094) lists as not enriched in small EVs of plasma-membrane/endosomal origin (category 4), and its own review keeps no experimental cell-surface or plasma-membrane pool; an exosome annotation from a bulk EV proteome is not supported. (Manual re-review for OMICS_EVIDENCE, 2026-10-10; previous action: KEEP_AS_NON_CORE.) Supporting Evidence: PMID:19056867 Here, we used LC-MS/MS to profile the proteome of human urinary exosomes. file:human/ARSL/ARSL-notes.md The study-authored NIH/NHLBI Urinary Exosome Protein Database lists arylsulfatase E precursor (ARSE; current symbol ARSL), RefSeq NP_000038, with one displayed peptide and reference 2, which links to PMID19056867. |
| GO:0003943 N-acetylgalactosamine-4-sulfatase activity | IMP PMID:42103217 Arylsulfatase L is a Golgi chondroitin sulfatase regulating ... | NEW | Summary: Propose the physiological GalNAc 4-O-desulfation activity supported by human ARSL rescue. Reason: Human wild-type ARSL, but not catalytic mutant C86A, corrects CS/DS 4-O-hypersulfation in rat RCS knockout cells. Golgi-enriched fractions from knockout and human-rescue cells also differ in their desulfation of added chondroitin sulfate. These complementary perturbation and fraction-assay results support the specific glycan activity. IMP records the human-construct rescue evidence; the experiment is not purified human enzyme kinetics or a complete substrate-range/endo-exo analysis. The current official GO definition describes GalNAc 4-sulfate hydrolysis in chondroitin/dermatan and contains no lysosomal-lumen clause; Golgi localization is preserved. This term is a sibling, not an ancestor or descendant, of the existing artificial aryl-sulfate activity. No direct TGF-beta signaling or new biological-process assertion is inferred. Supporting Evidence: PMID:42103217 Reintroducing the wild-type but not the catalytically inactive hARSL (hARSL C86A) normalized 4-O-sulfation levels of CS/DS in RCS Arsl KO cells PMID:42103217 To assess the ability of Arsl to directly desulfate chondroitin sulfate, we incubated exogenous CS molecules with Golgi-enriched fractions isolated from three RCS cell conditions: wild-type (WT), Arsl knockout (KO), and Arsl KO cells reconstituted with human ARSL (hARSL) PMID:42103217 Subsequent HPLC analysis of CS sulfation patterns revealed that 4-O-sulfation levels of CS were significantly elevated following incubation with Golgi fractions from Arsl KO cells, compared to those incubated with fractions from WT or hARSL-reconstituted cells |
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Q: How should Golgi chondroitin desulfation during proteoglycan maturation be represented within biosynthetic-process terms, in comparison with other glycan-modifying enzymes?
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