SH2 Domain-Containing Protein 1A,(SH2D1A) contains one SH2 domain and a short tail and is localized in the cytoplasm. SH2D1A is expressed at a high level in the thymus and the lung, with lower expression levels in the spleen and the liver. SH2D1A acts as an inhibitor of the signaling lymphocyte activation molecule (SLAM) self-association. In addition, SH2D1A mediates interaction between FYN and SLAMF1. It is also thought to regulate the activity of the neurotrophin receptors NTRK1, NTRK2 and NTRK3.