CASPL2B2

id: B9HD38
gene_symbol: CASPL2B2
product_type: PROTEIN
status: DRAFT
taxon:
  id: NCBITaxon:3694
  label: Populus trichocarpa
description: CASP-like protein 2B2 (PtCASPL2B2) 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 CASPL2B2 remain uncharacterized.
  The protein is predicted to form homodimers and heterodimers. In poplar, PtCASPL2B2 is expressed in
  developing xylem (xylem fiber cells, ~39 TPM) and phloem (EBI Expression Atlas E-GEOD-81077).
existing_annotations:
- term:
    id: GO:0005886
    label: plasma membrane
  evidence_type: IEA
  original_reference_id: GO_REF:0000044
  qualifier: located_in
  review:
    summary: CASPL2B2 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/CASPL2B2/CASPL2B2-uniprot.txt
      supporting_text: 'SUBCELLULAR LOCATION: Cell membrane'
    - reference_id: file:POPTR/CASPL2B2/CASPL2B2-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/CASPL2B2/CASPL2B2-uniprot.txt
  title: UniProtKB reviewed entry for CASPL2B2
  findings:
  - statement: UniProt identifies CASPL2B2 as a CASP-like protein of the Casparian strip membrane proteins
      family, a multi-pass cell membrane protein.
- id: file:POPTR/CASPL2B2/CASPL2B2-goa.tsv
  title: QuickGO GOA annotations for CASPL2B2
  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: PtCASPL2B2 is xylem-fiber/phloem-enriched, consistent with a wood/vascular role.
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/CASPL2B2/CASPL2B2-uniprot.txt
    supporting_text: 'SUBCELLULAR LOCATION: Cell membrane'
  - reference_id: file:POPTR/CASPL2B2/CASPL2B2-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 PtCASPL2B2 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 PtCASPL2B2 across
    poplar tissues to identify where it acts and whether it forms membrane microdomains.
  experiment_type: expression and localization profiling