CASP-like protein 1B2 (AtCASPL1B2, At4g20390) is a small tetraspan (four-transmembrane) plasma-membrane protein of the CASP-like (CASPL) subfamily of the MARVEL-related Casparian strip membrane domain protein family (CASPL1 clade). It is exclusively expressed in suberized endodermal cells and is one of four CASPLs (with CASPL1B1, CASPL1D1, CASPL1D2) that interact with the aquaporin PIP2;1, consistent with a membrane scaffold/adaptor role in the suberizing endodermis. Its experimentally determined location is the plasma membrane; no specific molecular function has been characterized, and CASPL loss of function does not detectably alter whole-root hydraulic conductivity.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005886 plasma membrane | IEA GO_REF:0000120 | ACCEPT | Summary: Correct, well-supported plasma-membrane localization for this multi-pass CASP-like protein. Reason: UniProt annotates a multi-pass cell-membrane protein and the localization is independently confirmed experimentally (IDA, PMID:24920445). Supporting Evidence: file:ARATH/CASPL1B2/CASPL1B2-uniprot.txt SUBCELLULAR LOCATION: Cell membrane |
| GO:0003674 molecular_function | ND GO_REF:0000015 | ACCEPT | Summary: Root-level placeholder reflecting that no specific molecular function has been characterized. Reason: No catalytic or transport activity is known for this CASP-like scaffold protein; the ND root annotation accurately reflects the absence of molecular-function data. Supporting Evidence: file:ARATH/CASPL1B2/CASPL1B2-goa.tsv molecular_function |
| GO:0005886 plasma membrane | IDA PMID:24920445 Functional and evolutionary analysis of the CASPARIAN STRIP ... | ACCEPT | Summary: Experimentally determined plasma-membrane localization; the core, well-grounded annotation. Reason: Direct assay in the family-defining study localizes this CASPL to the plasma membrane, consistent with the UniProt multi-pass topology. Supporting Evidence: file:ARATH/CASPL1B2/CASPL1B2-uniprot.txt SUBCELLULAR LOCATION: Cell membrane |
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Download this section (compressed HTML)Q: Does CASPL1B2 contribute, redundantly with CASPL1B1, to PIP2;1 regulation in the suberizing endodermis?
Experiment: Test CASPL1B2-PIP2;1 interaction and aquaporin regulation, and profile expression across endodermal differentiation zones.
Type: protein interaction and expression profiling
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