Gene Description

Equ c 1, the major horse allergen: a secreted lipocalin (calycin superfamily, lipocalin family) that binds small hydrophobic odorant ligands in its beta-barrel calyx. Produced in salivary, sublingual and liver tissue and shed in dander, it is the dominant horse allergen and a member of the cross-reactive mammalian lipocalin group (with cat Fel d 4, dog Can f 6 and bovine Bos d 2).

Existing Annotations Review

GO Term	Evidence	Action	Reason
GO:0005576 extracellular region	IBA GO_REF:0000033	ACCEPT	Summary: Equ c 1 is a secreted lipocalin; extracellular localization is well supported. Reason: Secretory lipocalin acting in the extracellular space. Supporting Evidence: file:HORSE/Equc1/Equc1-uniprot.txt SUBCELLULAR LOCATION: Secreted
GO:0005549 odorant binding	IBA GO_REF:0000033	ACCEPT	Summary: Equ c 1 binds small hydrophobic odorant ligands in its lipocalin calyx. Reason: Phylogenetic inference matching the odorant-binding lipocalin family. Supporting Evidence: file:HORSE/Equc1/Equc1-uniprot.txt Belongs to the calycin superfamily. Lipocalin family.
GO:0005576 extracellular region	IEA GO_REF:0000044	ACCEPT	Summary: Automated subcellular-location annotation consistent with secretion. Reason: Consistent with the secreted nature of the lipocalin. Supporting Evidence: file:HORSE/Equc1/Equc1-uniprot.txt SUBCELLULAR LOCATION: Secreted
GO:0036094 small molecule binding	IEA GO_REF:0000002	MARK AS OVER ANNOTATED	Summary: Generic parent of the more specific odorant binding already annotated. Reason: Uninformative broad parent; the specific odorant-binding activity is already captured.

Core Functions

Secreted odorant-binding lipocalin (major horse allergen, cross-reactive mammalian lipocalin group).

Molecular Function:

odorant binding

Cellular Locations:

extracellular region

Supporting Evidence:

file:HORSE/Equc1/Equc1-uniprot.txt
Belongs to the calycin superfamily. Lipocalin family.

References

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Suggested Experiments

Experiment: Compare ligand binding of recombinant Equ c 1, Fel d 4 and Can f 6 by fluorescent-probe displacement and map shared IgE epitopes by cross-inhibition.

Hypothesis: Equ c 1 shares ligand-binding specificity with the cross-reactive lipocalins Fel d 4 and Can f 6.

Type: biophysical / cross-reactivity assay

📚 Additional Documentation

Notes

(Equc1-notes.md)

Equc1 — curation notes (ALLERGENS backlog, mammalian inhalant cohort)

Equ c 1, major horse allergen; secreted odorant-binding lipocalin; cross-reactive lipocalin group (Fel d 4/Can f 6/Bos d 2). ACCEPT odorant binding+extracellular; over-annotated generic small molecule binding.

Equc1