Der p 23, a major house dust mite allergen associated with the peritrophic matrix of mite faecal pellets. It contains a peritrophin-A-type (ChtBD2) chitin-binding domain fold, but direct assays found no chitin binding in vitro, so its molecular function is unresolved. Despite its small size and minor abundance it is a major allergen, recognized by IgE in a large fraction of dust-mite-allergic patients.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005576 extracellular region | IEA GO_REF:0000120 | ACCEPT | Summary: Der p 23 is secreted/excreted with mite faecal pellets (peritrophic matrix); extracellular localization is correct. Reason: Excreted allergen of the faecal-pellet peritrophic matrix. |
| GO:0005783 endoplasmic reticulum | IEA GO_REF:0000044 | KEEP AS NON CORE | Summary: ER localization reflects the secretory route in mite gut cells. Reason: Biosynthetic/secretory-route compartment; not the functional site. |
| GO:0031410 cytoplasmic vesicle | IEA GO_REF:0000044 | KEEP AS NON CORE | Summary: Vesicular localization reflects the secretory route. Reason: Secretory-route compartment; not the functional site. |
| GO:0005576 extracellular region | IDA PMID:23460742 Identification of Der p 23, a peritrophin-like protein, as a... | ACCEPT | Summary: Der p 23 was experimentally localized to the peritrophic matrix of mite faecal pellets (excreted). Reason: Experimental support for extracellular/excreted localization. Supporting Evidence: PMID:23460742 peritrophic matrix of mite fecal pellets |
| GO:0008061 chitin binding | IDA NOT PMID:26602749 Serological, genomic and structural analyses of the major mi... | ACCEPT | Summary: This is a NOT (negated) annotation: GOA records that Der p 23 does NOT bind chitin. Despite its peritrophin-A (ChtBD2) chitin-binding-domain fold, direct assays (PMID:26602749) found no chitin binding in vitro, as also stated in UniProt. The negation is correct and informative. Reason: The negated annotation accurately captures the experimental finding that Der p 23 lacks chitin-binding activity in vitro; it correctly prevents domain-based over-annotation of chitin binding. Supporting Evidence: file:DERPT/Derp23/Derp23-uniprot.txt Does not bind chitin in vitro. |
| GO:0019863 IgE binding | IMP PMID:24733847 Conversion of Der p 23, a new major house dust mite allergen... | KEEP AS NON CORE | Summary: Der p 23 binds IgE (basis of its allergenicity and hypoallergen-vaccine design); this reflects allergenicity toward humans, not its endogenous mite function. Reason: Allergen/IgE-reactivity property, not the protein's endogenous molecular function. |
| GO:0031410 cytoplasmic vesicle | IDA PMID:23460742 Identification of Der p 23, a peritrophin-like protein, as a... | KEEP AS NON CORE | Summary: Experimental vesicular localization consistent with the secretory route. Reason: Secretory-route compartment; not the functional site. |
| GO:0005783 endoplasmic reticulum | IDA PMID:23460742 Identification of Der p 23, a peritrophin-like protein, as a... | KEEP AS NON CORE | Summary: Experimental ER localization consistent with the secretory route. Reason: Biosynthetic/secretory-route compartment; not the functional site. |
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Download this section (compressed HTML)Q: If Der p 23 does not bind chitin, what is the endogenous ligand/function of its peritrophin-A domain in the mite peritrophic matrix?
Experiment: Screen recombinant Der p 23 for binding to peritrophic-matrix glycans/glycoproteins by pull-down and glycan-array assays.
Hypothesis: Der p 23's peritrophin domain binds a peritrophic-matrix component other than chitin (e.g. a glycoprotein or glycan).
Type: ligand identification / binding assay
Der p 23, major mite allergen of faecal-pellet peritrophic matrix. Chitin binding is a NOT (negated) GOA annotation -> ACCEPT negation (does NOT bind chitin in vitro PMID:26602749) despite peritrophin-A domain. IgE binding KEEP_AS_NON_CORE. Function gap: true ligand/activity unknown.
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