A0A804UIX9

UniProt ID: A0A804UIX9
Organism: Zea mays
Review Status: DRAFT
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Gene Description

A0A804UIX9 is an uncharacterized PGG domain-containing protein from Zea mays (B73), encoded by gene model Zm00001eb381380 on chromosome 9 (canonical transcript T001, 375 amino acids; the alternative transcript T002 encodes A0A804R394). It has a disordered, polar N-terminal region (residues 1-44) followed by two tandem PGG domains (Pfam PF13962; residues 50-157 and 217-294) that carry six predicted transmembrane helices, so it is a predicted multi-pass integral membrane protein. Residues 1-297 are nearly identical to the neighbouring tandem paralog Zm00001eb380900 (A0A804R017), but the C-terminal ~78 residues are not conserved and appear to be a frame-shifted read-through, so the second PGG domain of this gene model probably lacks its final membrane-spanning segment. PANTHER places the protein in PTHR24177 (named CASKIN, but composed exclusively of plant PGG and ankyrin-PGG proteins), subfamily SF432, a grass/monocot-specific clade with no experimentally characterized member. The functionally studied PGG proteins of Arabidopsis and rice (ACD6, ITN1, NPR4) belong to a different PANTHER family (PTHR24186) and carry ankyrin repeats that this protein lacks. No experimental data exist for A0A804UIX9, and its molecular function and biological role are unknown.

Core Functions

Predicted multi-pass integral membrane protein built from two tandem PGG domains, with no experimentally established or phylogenetically transferable molecular activity. Its PANTHER family (PTHR24177) and subfamily (SF432) contain no characterized member. The characterized PGG proteins (ACD6, ITN1, NPR4) sit in a different PANTHER family and carry ankyrin repeats, so their activities are not transferred. The root molecular_function term records that the activity is unknown. Membrane localization rests on Phobius transmembrane predictions only.

Molecular Function:
molecular_function
Cellular Locations:
membrane
Supporting Evidence:
  • file:MAIZE/A0A804UIX9/A0A804UIX9-uniprot.txt
    FT TRANSMEM 54..73
  • file:MAIZE/A0A804UIX9/A0A804UIX9-uniprot.txt
    FT TRANSMEM 269..290
  • file:MAIZE/A0A804UIX9/A0A804UIX9-bioinformatics/RESULTS-rereview.md
    No member of PTHR24177 is a reviewed (Swiss-Prot) entry, and no member has experimentally
  • file:MAIZE/A0A804UIX9/A0A804UIX9-hypotheses/core-function-1-go-0003674/openscientist.md
    The assignment of GO:0003674 (the root molecular_function term) as the molecular function annotation for A0A804UIX9 is correct and reflects genuine uncertainty rather than annotation neglect.

References

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Suggested Questions for Experts

Q: What is the molecular function of PGG-only membrane proteins (PANTHER PTHR24177, Pfam PF13962 without ankyrin repeats)? Do they form channels or transporters like ACD6 does, even though they lack ankyrin repeats, or do they act as membrane scaffolds or partners of ankyrin-PGG proteins?

Q: Which Zm00001eb381380 transcript structure is real? The canonical T001 model ends in a non-conserved, apparently frame-shifted C-terminal tail. T002 splices out part of the conserved second PGG motif. Neither matches the tandem paralog Zm00001eb380900 along its whole length. Full-length cDNA or long-read evidence would settle the model.

Q: Why is the plant-only PANTHER family PTHR24177 named CASKIN, when it contains no metazoan members and human CASKIN1 is classified in PTHR24174?

Suggested Experiments

Experiment: Sequence full-length transcripts of Zm00001eb381380 by RT-PCR or Iso-Seq from B73 tissues where it is expressed. Compare them with T001 and T002, and with the tandem paralog Zm00001eb380900, to define the true coding sequence and the extent of the second PGG domain.

Hypothesis: The Zm00001eb381380 gene model is incorrect at its 3' end.

Type: transcript structure determination

Experiment: Express GFP-tagged A0A804UIX9 (corrected coding sequence) in maize protoplasts or Nicotiana benthamiana leaf epidermal cells. Image by confocal microscopy and co-stain with organelle markers for the ER, Golgi, plasma membrane and tonoplast.

Hypothesis: A0A804UIX9 is an integral membrane protein localized to a specific cellular membrane.

Type: fluorescence microscopy

Experiment: Generate CRISPR/Cas9 single and double knockouts of Zm00001eb381380 and Zm00001eb380900 in maize. Phenotype the lines under normal growth and under biotic and abiotic stress.

Hypothesis: A0A804UIX9 and its tandem paralog have a role in maize development or stress response.

Type: reverse genetics

External Prediction Reviews

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.

ProtNLM External predictions

View prediction review YAML · A0A804UIX9-protnlm-predictions-review.yaml · Review status: COMPLETE

ProtNLM2 made no predictions (GO or subcellular location) for PGG domain-containing protein. The model returned only a protein name. This absence is assessed as appropriate. The gene has no GOA annotations, no experimental data, and no PubMed literature (searches for the accession, gene model Zm00001eb381380, and PGG domain proteins in maize return nothing). The gene review describes a predicted multi-pass membrane protein built from two tandem PGG domains in a grass-specific PANTHER subfamily (PTHR24177:SF432) with no characterized member, and retains only the root molecular_function term, so there is no supported specific GO term the model missed. A membrane location could have been inferred from the predicted transmembrane helices, but no GO or location prediction was made to assess.

Source documents: genes/MAIZE/A0A804UIX9/A0A804UIX9-uniprot.txt · genes/MAIZE/A0A804UIX9/A0A804UIX9-goa.tsv

No GO/EC predictions in the reviewed source.

Deep Research

Falcon

(A0A804UIX9-deep-research-falcon.md)

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OpenScientist

(A0A804UIX9-hypotheses/core-function-1-go-0003674/openscientist.md)

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📚 Additional Documentation

Notes

(A0A804UIX9-notes.md)

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📄 View Raw YAML

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