CCL-9

Mouse CCL9/10 (also named MIP1γ and MRP2) is an 11 kDa, secreted, monomeric polypeptide that belongs to the β (or CC) intercrine family of chemokines. Based on its activity and amino acid (aa) sequence, it is further classified as a member of the NC6 or six cysteinecontaining CC subfamily of chemokines. This subfamily contains four Nterminally extended chemokines, two human (CCL15 and CCL23) and two mouse (CCL9 and CCL10) . Within this subfamily, there are no humanto rodent interspecies orthologs. Mouse CCL9/10 is synthesized as a 122 aa precursor that contains a 21 aa signal sequence and a 101 aa mature region with six cysteines. As noted, the mature region has an expanded Nterminus relative to other CC family members, and it forms a third intrachain disulfide bond with its two extra cysteines. Mouse CCL9/10 is 75% aa identical to rat CCL9/10. Chemokines are known to undergo proteolytic processing to generate multiple isoforms. NC6 chemokines are usually only marginally active at fulllength, but are converted to highly active forms upon Nterminal truncation. Mature CCL9, in the presence of inflammatory fluids, is naturally truncated by 28, 29 or 30 aa at the Nterminus, generating a highly active, 8 kDa, 71 73 aa CCR1 ligand. In contrast, other CCR1 ligands, CCL3/MIP1α and CCL5/RANTES, lose their potency when proteolytically processed. CCL9/10 is constitutively secreted, and circulates as a fulllength molecule. Any onset of inflammation with subsequent enzyme release may act on local NC6 chemokines, generating early, potent leukocyte chemoattractants.