The function of ENSG00000167302 (TEPSIN, TEPSIN adaptor related protein complex 4 accessory protein) is as follows. Associates with the adapter-like complex 4 (AP-4) and may therefore play a role in vesicular trafficking of proteins at the trans-Golgi network. {ECO:0000305|PubMed:22472443, ECO:0000305|PubMed:26542808}.