SLA2 is a 261 amino acid protein that exists as four alternatively spliced isoforms which localize to either the cytoplasm or to the cell membrane and contain one SH2 domain and one SH3 domain. Expressed predominately in tissues of the immune system, including thymus, spleen and lymph nodes, SLA2 functions as an adaptor protein that negatively regulates T-cell receptor (TCR) signaling and may inhibit T-cell activation. SLA2 interacts with Zap-70 and is subject to post-translational phosphorylation. The gene encoding SLA2 maps to human chromosome 20. Comprising approximately 2% of the human genome, chromosome 20 contains nearly 63 million bases that encode over 600 genes, some of which are associated with Creutzfeldt-Jakob disease, amyotrophic lateral sclerosis, spinal muscular atrophy, ring chromosome 20 epilepsy syndrome and Alagille syndrome.