Cleaves phosphorylated sphingoid bases (PSBs), such as sphingosine-1-phosphate, into fatty aldehydes and phosphoethanolamine (PubMed:9464245, PubMed:20097939). Elevates stress-induced ceramide production and apoptosis (PubMed:9464245). Required for global lipid homeostasis in liver and cholesterol homeostasis in fibroblasts (PubMed:20097939, PubMed:28262793). Involved in the regulation of pro-inflammatory response and neutrophil trafficking (PubMed:21173151). Modulates neuronal autophagy via phosphoethanolamine production which regulates accumulation of aggregate-prone proteins such as APP (PubMed:28521611). Seems to play a role in establishing neuronal contact sites and axonal maintenance (By similarity). sphinganine 1-phosphate = hexadecanal + phosphoethanolamine sphing-4-enine 1-phosphate = (2E)-hexadecenal + phosphoethanolamine Lipid metabolism; sphingolipid metabolism. Highest levels are found in liver, small intestine and thymus, followed by kidney, lung, heart, spleen and brain (at protein level). Also detected in stomach, testis and skeletal muscle (at protein level). Expressed throughout mouse embryogenesis.A transient increase is observed from 5.5 dpc to 7.5 dpc. Mutant animals have a shortened lifespan (PubMed:21173151). Mutant mice show an increase of sphingoid base phosphates, but also other sphingolipids (including sphingosine, ceramide, and sphingomyelin) in the serum and/or liver, resulting in changes in the levels of serum and liver lipids not directly within the sphingolipid pathway, including phospholipids, triacyglycerol, diacylglycerol, and cholesterol (PubMed:20097939). They are deficient in B and T lymphocytes yet have high blood levels of neutrophils and monocytes along with elevated expression of pro-inflammatory cytokines. Their tissues are largely clear of infiltrating leukocytes and their neutrophils are defective in migration to chemotactic stimulus (PubMed:21173151). Mice lacking Sgpl1 exhibit complete podocyte foot process effacement and absence of slit diaphragms in kidney (PubMed:9464245, PubMed:28165339). They display hypoalbuminemia and an elevated urinary albumin/creatinine ratio (PubMed:28165339). They also display abnormal adrenal gland morphology and defective expression of enzymes involved in steroidogenesis in this tissue (PubMed:28165343). Conditional knockout in brain significantly reduces phosphoethanolamine levels with alterations in basal and stimulated autophagy involving decreased conversion of LC3-I to LC3-II, increased levels of lysosomal markers and aggregate-prone proteins such as APP and SNCA. Animals show profound deficits in cognitive skills (PubMed:28521611). Belongs to the group II decarboxylase family. Sphingosine-1-phosphate lyase subfamily.