A0A2I4G8T1 is a UDP-glycosyltransferase from Juglans regia (English walnut), belonging to the UGT73C subfamily based on PANTHER classification (PTHR48047:SF229, UDP-GLYCOSYLTRANSFERASE 73C3-RELATED). The 488-amino-acid protein contains a GT1_Gtf-like catalytic domain and a C-terminal UDP-glycosyltransferase signature motif (UDPGT/Pfam PF00201), along with an N-terminal glycosyltransferase domain (Pfam PF26168). As a GT1 family glycosyltransferase, it catalyzes the transfer of sugar moieties from UDP-sugar donors to small-molecule acceptors. In plants, UGT73C family members are known to glycosylate diverse substrates including brassinosteroids, cytokinins, flavonoids, and other phenolic compounds, thereby modulating hormone homeostasis and secondary metabolism. The protein is encoded on chromosome 3 and its function is inferred entirely from homology, with no direct experimental characterization reported.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0035251 UDP-glucosyltransferase activity | IBA GO_REF:0000033 | ACCEPT | Summary: This IBA annotation is derived from phylogenetic inference (PANTHER) based on orthology to six Arabidopsis UDP-glucosyltransferases (AT1G73880/UGT73C3, AT2G36750, AT2G36790, AT2G36800, AT3G53160, AT5G03490). The protein contains all expected domains (GT1_Gtf-like catalytic domain, UDPGT Pfam domain, UDP-glycosyltransferase signature) and is classified in PANTHER subfamily SF229 (UDP-GLYCOSYLTRANSFERASE 73C3-RELATED). UDP-glucosyltransferase activity (GO:0035251) is more specific than the parent term UDP-glycosyltransferase activity, specifying glucose as the sugar donor. This is well supported by the phylogenetic context. Reason: The phylogenetic placement with multiple Arabidopsis UGT73 family members, combined with domain architecture (GT1_Gtf-like, UDPGT, UDP_glycos_trans_CS), strongly supports UDP-glucosyltransferase activity. This is the most specific and informative annotation among the three. |
| GO:0008194 UDP-glycosyltransferase activity | IEA GO_REF:0000002 | KEEP AS NON CORE | Summary: This IEA annotation comes from the InterPro domain IPR002213 (UDP-glucosyltransferase), which is present in the protein. The annotation to GO:0008194 (UDP-glycosyltransferase activity) is correct but is a parent term of the more specific GO:0035251 (UDP-glucosyltransferase activity) already assigned by IBA. It is redundant given the more specific annotation. Reason: This is a true parent term of GO:0035251. The protein does have UDP-glycosyltransferase activity, but the more specific UDP-glucosyltransferase activity better captures its function. Keeping as non-core since it is correct but less informative. |
| GO:0016757 glycosyltransferase activity | IEA GO_REF:0000117 | MARK AS OVER ANNOTATED | Summary: This IEA annotation from ARBA assigns the very broad parent term glycosyltransferase activity (GO:0016757). While correct, this is overly general given that more specific terms (GO:0035251, GO:0008194) are already assigned. GO:0016757 encompasses all glycosyltransferases regardless of donor substrate, while this protein clearly belongs to the UDP-dependent GT1 family. Reason: This is the broadest of the three molecular function annotations and adds no information beyond what is captured by the more specific terms. The protein's domain architecture and phylogenetic placement clearly place it in the UDP-glycosyltransferase family, making this overly general annotation uninformative. |
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Download this section (compressed HTML)Q: What are the in vivo acceptor substrates of this UGT73C-related glucosyltransferase in Juglans regia? Walnut produces abundant naphthoquinones (e.g. juglone) and phenolics that could be glycosylation targets.
Q: Does this enzyme glycosylate juglone (5-hydroxy-1,4-naphthoquinone), the characteristic allelochemical of walnut, potentially serving a detoxification or storage role?
Experiment: In vitro substrate screening of recombinant A0A2I4G8T1 with UDP-glucose and candidate acceptors including juglone, quercetin, kaempferol, brassinolide, and trans-zeatin to determine substrate specificity.
Hypothesis: Given its UGT73C subfamily classification and the prominence of juglone in walnut metabolism, the enzyme may glycosylate juglone or related naphthoquinones as a detoxification mechanism.
Experiment: Expression profiling of LOC109005703 across walnut tissues (leaves, roots, hull, bark) and developmental stages to identify where glycosylation activity is most needed.
Hypothesis: Expression may be highest in tissues with active secondary metabolism or juglone production, suggesting a role in phenolic compound homeostasis.
These computational predictions are reviewed separately from the GOA annotation set used for this review. The assessments below are from this project and do not constitute official GO annotations or endorsement by GO/UniProt. They are not included in the existing annotation review above.
View prediction review YAML · A0A2I4G8T1-protnlm-predictions-review.yaml · Review status: COMPLETE
ProtNLM2 made no predictions (GO or subcellular location) for UDP-glycosyltransferase 73C1. The model returned only a protein name.
Source documents: genes/JUGRE/A0A2I4G8T1/A0A2I4G8T1-uniprot.txt · genes/JUGRE/A0A2I4G8T1/A0A2I4G8T1-goa.tsv
No GO/EC predictions in the reviewed source.
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