Selected accession A0A9L0T1D1; ordinary UniProt record is TrEMBL and cites genome sequencing/submission rather than a gene-specific functional experiment. Human evidence is summarized in the paired human investigation. Sequence comparison records the exact target gaps and transfer limits. Direct horse CXCR3 expression evidence exists (PMID:31256888), motivating a horse-specific Edison request; expression is not a ligand-binding validation.
CXCR3-A and CXCR3-B share the seven-transmembrane receptor core but differ at the N terminus and in signaling behavior. In the directly inspected Lasagni study, CXCR3-A supports cell survival/proliferation, whereas CXCR3-B supports endothelial growth inhibition and apoptosis; CXCL4 preferentially binds the B isoform. The paper explicitly includes a negative competition panel containing CCL3, CCL4 and CCL5/RANTES. That experiment is decisive against treating the named ligand list in the horse model output as established. It does not prove that every conceivable CC ligand fails to interact with every CXCR3 isoform. The C-C receptor/binding IBA annotations require tracing the curated ancestral claim and its actual experimental grounding, not counting donor proteins.
Sources: PMID:12782716(https://pubmed.ncbi.nlm.nih.gov/12782716/), PMID:31256888(https://pubmed.ncbi.nlm.nih.gov/31256888/).
The horse Falcon/Edison report completed and is preserved as CXCR3-deep-research-falcon.md with its artifact. It distinguishes direct horse expression evidence from mammalian receptor-mechanism transfer and identifies exercise-expression and EHV-1 chemokine studies as further source leads. The EHV-1 migration study does not directly block or disrupt CXCR3, so it is not treated as receptor-specific validation. The independently checked human ligand experiments remain the basis for the ProtNLM ligand-specificity assessment.