CASP-like protein 3A2 (PtCASPL3A2) 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 CASPL3A2 remain uncharacterized. The protein is predicted to form homodimers and heterodimers. In poplar, PtCASPL3A2 is phloem-enriched (~55 TPM) and is cold- and salt-induced in root/stem xylem (EBI Expression Atlas E-GEOD-81077 / E-MTAB-5540).
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005886 plasma membrane | IEA GO_REF:0000044 | ACCEPT | Summary: CASPL3A2 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. 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. Supporting Evidence: file:POPTR/CASPL3A2/CASPL3A2-uniprot.txt SUBCELLULAR LOCATION: Cell membrane file:POPTR/CASPL3A2/CASPL3A2-uniprot.txt DR GO; GO:0005886; C:plasma membrane; IEA:UniProtKB-SubCell. |
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Download this section (compressed HTML)Q: In which tissues is PtCASPL3A2 expressed, and does it organize a distinct plasma-membrane microdomain like the bona fide CASP proteins or serve a different role?
Experiment: Determine the expression pattern and subcellular localization of tagged PtCASPL3A2 across poplar tissues to identify where it acts and whether it forms membrane microdomains.
Type: expression and localization profiling
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