ubl-1

id: P37164
gene_symbol: ubl-1
product_type: PROTEIN
status: INITIALIZED
taxon:
  id: NCBITaxon:6238
  label: Caenorhabditis briggsae
description: >-
  ubl-1 encodes a bifunctional ubiquitin-like protein 1-ribosomal protein eS31 fusion
  protein (the Caenorhabditis briggsae ortholog of the RPS27A/UBA80-type fusion). It is
  synthesized as a single precursor in which an N-terminal ubiquitin-like domain (residues
  1-70) is fused to the C-terminal small ribosomal subunit protein eS31 (40S ribosomal
  protein S27a; residues 71-163). The precursor is co-translationally cleaved by
  deubiquitinating enzymes to release two products with distinct functions. The N-terminal
  moiety is a ubiquitin-like protein that, once liberated, contributes to the cellular pool
  of free ubiquitin used to covalently tag substrate proteins, marking them for
  modification-dependent fates including proteasomal degradation. The C-terminal moiety is a
  zinc-finger-containing structural protein of the small (40S) ribosomal subunit that is
  required for translation; fusion to the ubiquitin-like domain is thought to aid its
  folding, stability, and incorporation into the ribosome. The mature ribosomal protein
  localizes to the cytosolic ribosome, and the released ubiquitin moiety acts in protein
  ubiquitination throughout the cell.
existing_annotations:
- term:
    id: GO:0005634
    label: nucleus
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: is_active_in
  review:
    summary: >-
      Phylogenetic (IBA) localization to the nucleus, propagated across the ribosomal protein
      eS31/ubiquitin fusion family. Ribosomal protein assembly begins in the nucleolus/nucleus
      and free ubiquitin acts throughout the cell including the nucleus, so a nuclear location
      is biologically plausible but is not a core, defining localization of this gene product.
      Kept as a non-core localization.
    action: KEEP_AS_NON_CORE
- term:
    id: GO:0003735
    label: structural constituent of ribosome
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: enables
  review:
    summary: >-
      Core molecular function of the C-terminal eS31 (RPS27a) moiety. After cleavage of the
      ubiquitin-like domain, the mature ribosomal protein is a structural constituent of the
      small (40S) ribosomal subunit. Strongly supported by family-wide phylogenetic evidence
      and by the conserved eS31 domain architecture (zinc-finger ribosomal fold). Accepted as
      a core function.
    action: ACCEPT
- term:
    id: GO:0022626
    label: cytosolic ribosome
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: is_active_in
  review:
    summary: >-
      Correct cellular location for the mature eS31 ribosomal protein, which functions as part
      of the cytosolic 40S ribosomal subunit during translation. Consistent with the structural
      constituent of ribosome function and the eS31 family. Accepted.
    action: ACCEPT
- term:
    id: GO:0031386
    label: protein tag activity
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: enables
  review:
    summary: >-
      Captures the core molecular function of the N-terminal ubiquitin-like moiety. After
      cleavage, the released ubiquitin-like protein is covalently conjugated to substrate
      lysines (an isopeptide crosslink is annotated at Gly70) and serves as a tag marking
      proteins for downstream fates. This is the canonical ubiquitin/ubiquitin-like function and
      a defining role of the gene's bifunctional product. Accepted as a core function.
    action: ACCEPT
- term:
    id: GO:0019941
    label: modification-dependent protein catabolic process
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: involved_in
  review:
    summary: >-
      The free ubiquitin released from the fusion contributes to the cellular ubiquitin pool used
      to target substrates for proteasomal (modification-dependent) degradation. This is a
      downstream process role of the ubiquitin moiety rather than the gene product's own defining
      molecular function, but it is a genuine and well-supported aspect of ubiquitin biology.
      Retained as a non-core process annotation.
    action: KEEP_AS_NON_CORE
- term:
    id: GO:0016567
    label: protein ubiquitination
  evidence_type: IBA
  original_reference_id: GO_REF:0000033
  qualifier: involved_in
  review:
    summary: >-
      The cleaved ubiquitin-like moiety supplies free ubiquitin for conjugation onto target
      proteins, so involvement in protein ubiquitination is correct. This is the biological-process
      counterpart of the protein tag activity function. Retained as a non-core process annotation
      reflecting the ubiquitin side of this bifunctional product.
    action: KEEP_AS_NON_CORE
- term:
    id: GO:0003735
    label: structural constituent of ribosome
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  qualifier: enables
  review:
    summary: >-
      InterPro-based electronic annotation (IPR002906, ribosomal eS31) corroborating the IBA
      structural constituent of ribosome call. Consistent with the C-terminal eS31 domain and the
      core ribosomal function. Accepted.
    action: ACCEPT
- term:
    id: GO:0005840
    label: ribosome
  evidence_type: IEA
  original_reference_id: GO_REF:0000002
  qualifier: located_in
  review:
    summary: >-
      InterPro-derived (IPR002906) localization to the ribosome. Correct but more general than the
      cytosolic ribosome (GO:0022626) term already annotated by IBA. The mature eS31 protein is a
      cytosolic 40S subunit component, so the more specific term better reflects the location.
    action: MODIFY
    proposed_replacement_terms:
    - id: GO:0022626
      label: cytosolic ribosome
- term:
    id: GO:0006412
    label: translation
  evidence_type: IEA
  original_reference_id: GO_REF:0000120
  qualifier: involved_in
  review:
    summary: >-
      Automated multi-method (ARBA/InterPro) annotation to translation, the biological process in
      which the eS31 ribosomal protein participates as a 40S subunit constituent. Correct and
      consistent with the structural constituent of ribosome function, though it is a broad process
      term rather than the gene's defining molecular function. Retained as a non-core process.
    action: KEEP_AS_NON_CORE
core_functions:
- description: >-
    Structural constituent of the small (40S) cytosolic ribosomal subunit. The mature C-terminal
    eS31 (RPS27a) moiety, released after cleavage of the ubiquitin-like domain, is a zinc-finger
    ribosomal protein that assembles into the 40S subunit and is required for translation.
  molecular_function:
    id: GO:0003735
    label: structural constituent of ribosome
  locations:
  - id: GO:0022626
    label: cytosolic ribosome
- description: >-
    Ubiquitin-like protein tag. The N-terminal ubiquitin-like moiety, after proteolytic release from
    the fusion, contributes free ubiquitin that is covalently conjugated to substrate proteins
    (isopeptide-linked via Gly70), tagging them for modification-dependent fates including proteasomal
    degradation.
  molecular_function:
    id: GO:0031386
    label: protein tag activity
references:
- id: GO_REF:0000002
  title: Gene Ontology annotation through association of InterPro records with GO
    terms
  findings: []
- id: GO_REF:0000033
  title: Annotation inferences using phylogenetic trees
  findings: []
- id: GO_REF:0000120
  title: Combined Automated Annotation using Multiple IEA Methods
  findings: []