May play a role as a negative regulatory factor in CD4-dependent T-cell activation. Interacts with CD4. Interacts with ALDH16A1. Partially localized in the cytosol but also accumulated on an intracellular vesicular compartment. Colocalizes with CD4 on endosomal/trans-Golgi network. Expressed in all tissues tested, including heart, brain, placenta, lung, liver, skeletal muscle, kidney and pancreas. Expressed in J.CaM1.6, HuT 78 and HeLa cell lines (at protein level). The disease is caused by variants affecting the gene represented in this entry. Belongs to the AB hydrolase superfamily.