Involved in the regulation of endocytosis and in several stages of intracellular trafficking (PubMed:12668730, PubMed:17994011, PubMed:32513819, PubMed:33468622). Plays a role in recycling endocytosed transferrin receptor and prevent its degradation (PubMed:17994011). Involved in autophagosome assembly by regulating trafficking and recycling of phospholipid scramblase ATG9A (PubMed:32513819, PubMed:33468622). {ECO:0000269|PubMed:12668730, ECO:0000269|PubMed:17994011, ECO:0000269|PubMed:32513819, ECO:0000269|PubMed:33468622}. This is the function of SNX4 (sorting nexin 4, Ensembl gene identifier ENSG00000114520).