id: A4GYT9
gene_symbol: psbN
product_type: PROTEIN
status: DRAFT
taxon:
  id: NCBITaxon:3694
  label: Populus trichocarpa
description: Chloroplast thylakoid membrane protein PsbN, a putative photosystem I/II biogenesis factor that is probably not a stable PSII core subunit.
existing_annotations:
- term:
    id: GO:0009535
    label: chloroplast thylakoid membrane
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  review:
    summary: Chloroplast thylakoid membrane is the correct localization for psbN.
    action: ACCEPT
    reason: UniProt places PsbN in the chloroplast thylakoid membrane.
    supported_by:
    - reference_id: file:POPTR/psbN/psbN-uniprot.txt
      supporting_text: 'SUBCELLULAR LOCATION: Plastid, chloroplast thylakoid membrane'
- term:
    id: GO:0015979
    label: photosynthesis
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  review:
    summary: Photosynthesis is broad pathway context for a putative photosystem biogenesis factor.
    action: KEEP_AS_NON_CORE
    reason: UniProt says PsbN may play a role in photosystem I and II biogenesis, but also cautions that it is probably not a PSII component.
    supported_by:
    - reference_id: file:POPTR/psbN/psbN-uniprot.txt
      supporting_text: May play a role in photosystem I and II biogenesis.
    - reference_id: file:POPTR/psbN/psbN-uniprot.txt
      supporting_text: Originally thought to be a component of PSII; based on experiments in Synechocystis, N.tabacum and barley, and its absence from PSII in T.elongatus and T.vulcanus, this is probably not true.
- term:
    id: GO:0016020
    label: membrane
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  review:
    summary: Membrane is correct but too broad for PsbN.
    action: MODIFY
    reason: Use the specific chloroplast thylakoid membrane localization supported by UniProt.
    supported_by:
    - reference_id: file:POPTR/psbN/psbN-uniprot.txt
      supporting_text: 'SUBCELLULAR LOCATION: Plastid, chloroplast thylakoid membrane'
    proposed_replacement_terms:
    - id: GO:0009535
      label: chloroplast thylakoid membrane
references:
- id: GO_REF:0000002
  title: Gene Ontology annotation through association of InterPro records with GO terms
  findings:
  - statement: GO_REF:0000002 supplied one or more source GOA annotations reviewed in this file.
- id: GO_REF:0000120
  title: Combined Automated Annotation using Multiple IEA Methods
  findings:
  - statement: GO_REF:0000120 supplied one or more source GOA annotations reviewed in this file.
- id: file:POPTR/psbN/psbN-uniprot.txt
  title: UniProtKB reviewed entry for psbN
  findings:
  - statement: UniProt identifies psbN as a chloroplast thylakoid membrane protein that may function in photosystem I and II biogenesis, with a caution that it is probably not a PSII component.
- id: file:POPTR/psbN/psbN-goa.tsv
  title: QuickGO GOA annotations for psbN
  findings:
  - statement: GOA rows supplied the existing_annotations reviewed in this file.
core_functions:
- description: Acts as a chloroplast thylakoid membrane protein with a probable role in photosystem biogenesis rather than as a stable photosystem II core subunit.
  locations:
  - id: GO:0009535
    label: chloroplast thylakoid membrane
  supported_by:
  - reference_id: file:POPTR/psbN/psbN-uniprot.txt
    supporting_text: May play a role in photosystem I and II biogenesis.
  - reference_id: file:POPTR/psbN/psbN-uniprot.txt
    supporting_text: 'SUBCELLULAR LOCATION: Plastid, chloroplast thylakoid membrane'
  - reference_id: file:POPTR/psbN/psbN-uniprot.txt
    supporting_text: Originally thought to be a component of PSII; based on experiments in Synechocystis, N.tabacum and barley, and its absence from PSII in T.elongatus and T.vulcanus, this is probably not true.
suggested_questions:
- question: Should Populus PsbN be annotated to a specific photosystem biogenesis or assembly process, and is the evidence strong enough despite the UniProt caution that it is probably not a PSII component?
suggested_experiments:
- description: Test PSI/PSII assembly and accumulation by blue-native PAGE and chlorophyll fluorescence in psbN perturbation or plastid-editing lines.
  experiment_type: targeted functional assay
proposed_new_terms: []