The function of NOX5 (NADPH oxidase 5, ENSG00000255346) is as follows. Calcium-dependent NADPH oxidase that catalyzes the generation of superoxide from molecular oxygen utilizing NADPH as an electron donor (PubMed:12686516). Also synthesizes NAADP from its reduced NAADPH form which promotes Ca(2+) signaling during T cell activation (PubMed:34784249). May play a role in cell growth and apoptosis (PubMed:12686516). {ECO:0000269|PubMed:12686516, ECO:0000269|PubMed:34784249}. [Isoform v2]: Calcium-dependent NADPH oxidase that catalyzes the generation of superoxide from molecular oxygen utilizing NADPH as an electron donor (PubMed:11483596, PubMed:14982937, PubMed:17275676, PubMed:17587483, PubMed:21642394, PubMed:22387196, PubMed:22427510, PubMed:24505490, PubMed:36653838). Involved in endothelial generation of reactive oxygen species (ROS), proliferation and angiogenesis and contributes to endothelial response to thrombin (PubMed:17275676). Regulates redox-dependent processes in lymphocytes and spermatozoa (PubMed:11483596). {ECO:0000269|PubMed:11483596, ECO:0000269|PubMed:14982937, ECO:0000269|PubMed:17275676, ECO:0000269|PubMed:17587483, ECO:0000269|PubMed:21642394, ECO:0000269|PubMed:22387196, ECO:0000269|PubMed:22427510, ECO:0000269|PubMed:24505490, ECO:0000269|PubMed:36653838}. [Isoform v1]: Calcium-dependent NADPH oxidase that catalyzes the generation of superoxide from molecular oxygen utilizing NADPH as an electron donor. {ECO:0000269|PubMed:21319793, ECO:0000269|PubMed:22427510}. [Isoform v5]: This isoform lacks calcium-binding domains and was showed to present a NADPH oxidase activity in a calcium-independent manner (PubMed:17275676, PubMed:36653838). May be involved in endothelial generation of reactive oxygen species (ROS), proliferation and angiogenesis and contribute to endothelial response to thrombin (PubMed:17275676). However another study showed an absence of oxidase activity (PubMed:22427510). Subject to rapid degradation (PubMed:36653838). {ECO:0000269|PubMed:17275676, ECO:0000269|PubMed:22427510, ECO:0000269|PubMed:36653838}. [Isoform v3]: Lacks calcium-dependent NADPH oxidase activity. . [Isoform v4]: Lacks calcium-dependent NADPH oxidase activity. .