The function of Ensembl gene identifier ENSG00000143669 (LYST, lysosomal trafficking regulator) is as follows. Adapter protein that regulates and/or fission of intracellular vesicles such as lysosomes (PubMed:11984006, PubMed:25216107). Might regulate trafficking of effectors involved in exocytosis (PubMed:25425525). In cytotoxic T-cells and natural killer (NK) cells, has role in the regulation of size, number and exocytosis of lytic granules (PubMed:26478006). In macrophages and dendritic cells, regulates phagosome maturation by controlling the conversion of early phagosomal compartments into late phagosomes (By similarity). In macrophages and dendritic cells, specifically involved in TLR3- and TLR4-induced production of pro-inflammatory cytokines by regulating the endosomal TLR3- TICAM1/TRIF and TLR4- TICAM1/TRIF signaling pathways (PubMed:27881733). {ECO:0000250|UniProtKB:P97412, ECO:0000269|PubMed:11984006, ECO:0000269|PubMed:25216107, ECO:0000269|PubMed:25425525, ECO:0000269|PubMed:26478006, ECO:0000269|PubMed:27881733}.