CASPL4D1

id: B9NBE5
gene_symbol: CASPL4D1
product_type: PROTEIN
status: DRAFT
taxon:
  id: NCBITaxon:3694
  label: Populus trichocarpa
description: CASP-like protein 4D1 (PtCASPL4D1) is a small tetraspan membrane protein belonging to the
  CASP-like (CASPL) subfamily, the more divergent relatives of the bona fide Casparian strip membrane
  domain proteins (CASP1-5). Like other family members it has a central MARVEL-like four-transmembrane
  domain and is predicted to reside in the plasma membrane as a multi-pass protein. CASP-like proteins
  are not enzymes; by analogy with the characterized CASP scaffolds they are thought to organize plasma-membrane
  microdomains, but the specific biological role and tissue context of CASPL4D1 remain uncharacterized.
  The protein is predicted to form homodimers and heterodimers. In poplar, PtCASPL4D1 shows low, primary-root-enriched
  baseline expression and is strongly drought-induced in stem xylem (log2FC +5.1) while repressed by cold/heat
  in root (EBI Expression Atlas E-MTAB-5540).
existing_annotations:
- term:
    id: GO:0005886
    label: plasma membrane
  evidence_type: IEA
  original_reference_id: GO_REF:0000044
  qualifier: located_in
  review:
    summary: CASPL4D1 is a multi-pass membrane protein of the CASP-like family; plasma membrane localization
      is the supported cellular component and the only well-grounded annotation for this otherwise uncharacterized
      protein.
    action: ACCEPT
    reason: UniProt reports cell membrane (plasma membrane) localization as a multi-pass membrane protein,
      consistent with the CASP/CASPL family and the four predicted transmembrane helices in the sequence
      record.
    supported_by:
    - reference_id: file:POPTR/CASPL4D1/CASPL4D1-uniprot.txt
      supporting_text: 'SUBCELLULAR LOCATION: Cell membrane'
    - reference_id: file:POPTR/CASPL4D1/CASPL4D1-uniprot.txt
      supporting_text: DR   GO; GO:0005886; C:plasma membrane; IEA:UniProtKB-SubCell.
references:
- id: GO_REF:0000044
  title: Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping,
    accompanied by conservative changes to GO terms applied by UniProt
  findings:
  - statement: GO_REF:0000044 supplied the plasma membrane GOA annotation reviewed in this file.
- id: file:POPTR/CASPL4D1/CASPL4D1-uniprot.txt
  title: UniProtKB reviewed entry for CASPL4D1
  findings:
  - statement: UniProt identifies CASPL4D1 as a CASP-like protein of the Casparian strip membrane proteins
      family, a multi-pass cell membrane protein.
- id: file:POPTR/CASPL4D1/CASPL4D1-goa.tsv
  title: QuickGO GOA annotations for CASPL4D1
  findings:
  - statement: GOA supplied the plasma membrane annotation reviewed in this file.
- id: PMID:24920445
  title: Functional and evolutionary analysis of the CASPARIAN STRIP MEMBRANE DOMAIN PROTEIN family.
  findings:
  - statement: Defines the CASP/CASPL family and distinguishes the divergent, largely uncharacterized
      CASP-like subfamily from the bona fide Casparian strip CASP proteins.
  reference_review:
    relevance: HIGH
    correctness: VERIFIED
    review_notes: PubMed-verified; family-defining paper that establishes the CASP/CASPL nomenclature
      and the uncharacterized status of the CASP-like subfamily to which this protein belongs.
- id: file:projects/CASPL_FAMILY/bioinformatics/expression/RESULTS.md
  title: Poplar CASPL expression analysis (EBI Expression Atlas) - RESULTS
  findings:
  - statement: PtCASPL4D1 is root-enriched and markedly drought-responsive in xylem.
core_functions:
- description: Predicted plasma-membrane CASP-like family protein of uncharacterized specific function,
    inferred to act in organizing plasma-membrane microdomains.
  supported_by:
  - reference_id: file:POPTR/CASPL4D1/CASPL4D1-uniprot.txt
    supporting_text: 'SUBCELLULAR LOCATION: Cell membrane'
  - reference_id: file:POPTR/CASPL4D1/CASPL4D1-uniprot.txt
    supporting_text: Belongs to the Casparian strip membrane proteins (CASP)
  locations:
  - id: GO:0005886
    label: plasma membrane
proposed_new_terms: []
suggested_questions:
- question: In which tissues is PtCASPL4D1 expressed, and does it organize a distinct plasma-membrane
    microdomain like the bona fide CASP proteins or serve a different role?
suggested_experiments:
- description: Determine the expression pattern and subcellular localization of tagged PtCASPL4D1 across
    poplar tissues to identify where it acts and whether it forms membrane microdomains.
  experiment_type: expression and localization profiling