CCL3L1 Full-Length MS Protein Standard (NP_066286), Labeled with [U- 13C6, 15N4]-L-Arginine and [U- 13C6, 15N2]-L-Lysine, was produced in human 293 cells (HEK293) with fully chemically defined cell culture medium to obtain incorporation efficiency at Creative-Proteomics. This gene is one of several cytokine genes that are clustered on the q-arm of chromosome 17. Cytokines are a family of secreted proteins that function in inflammatory and immunoregulatory processes. The protein encoded by this gene binds to several chemokine receptors, including chemokine binding protein 2 and chemokine (C-C motif) receptor 5 (CCR5). CCR5 is a co-receptor for HIV, and binding of this protein to CCR5 inhibits HIV entry. The copy number of this gene varies among individuals, where most individuals have one to six copies, and a minority of individuals have zero or more than six copies. There are conflicting reports about copy number variation of this gene and its correlation to disease susceptibility. This record represents one of two copies that are present on the ALT_REF_LOCI_2 alternate haplotype of the GRCh38 human reference genome assembly. Alternative splicing of this gene results in multiple transcript variants.