The function of ENSG00000125637 (PSD4, pleckstrin and Sec7 domain containing 4) is as follows. Guanine nucleotide exchange factor for ARF6 and ARL14/ARF7. Through ARL14 activation, controls the movement of MHC class II- containing vesicles along the actin cytoskeleton in dendritic cells. Involved in membrane recycling. Interacts with several phosphatidylinositol phosphate species, including phosphatidylinositol 3,4-bisphosphate, phosphatidylinositol 3,5-bisphosphate and phosphatidylinositol 4,5-bisphosphate. {ECO:0000269|PubMed:12082148, ECO:0000269|PubMed:21458045}.