Mouse TCA‑3 is a member of the CC beta family of chemokines, designated CCL1. The human chemokine I-309, which shares approximately 42% amino acid (aa) sequence identity, is the orthologue of mouse TCA‑3. Mouse TCA‑3 and human I-309 also share significant sequence homology in the 5' flanking region of their genes and each contain an extra pair of cysteine residues not found in most other chemokines.
TCA‑3 cDNA encodes a 92 aa precursor protein with a predicted 23 aa signal peptide that is cleaved to produce a 69 aa mature protein. The sequence of TCA‑3 contains one potential N-linked glycosylation site. Mouse TCA‑3 is found on the distal portion of mouse chromosome 11 in a cluster with MIP-1 alpha, MIP-1 beta and JE. TCA‑3 acts by binding to the seven transmembrane spanning G-protein-coupled receptor, CCR8. TCA‑3 has been shown to chemoattract T-cells.