Anti-SIP1 receptor/Edg-1

S1PR1 (Sphingosine-1-phosphate receptor 1) is a G-protein coupled receptor, which binds the bioactive S1P (sphingolipid, sphingosine-1-phosphate) as a high affinity ligand. S1P is present at high levels in blood and lymph, and plays a critical role in the homeostasis of the vascular and immune systems. S1PR1 was originally identified as an abundant transcript in endothelial cells and plays a key role in regulating endothelial cell cytoskeletal structure, migration, capillary-like network formation and vascular maturation. In the immune system, S1PR1 signaling is important in the regulation of lymphocyte migration and trafficking. Inhibition of S1PR1 results in lymphocyte sequestration within lymphoid organs. S1PR1 may also regulate tumor cell functions in some types of B cell lymphoma. Inhibition of S1PR1 expression down regulates signal transducer and activator of transcription 3 activity, leading to inhibition of lymphoma tumor cell growth. S1PR1 signaling in T cells drives Treg accumulation in tumors, limits CD8+ T cell recruitment and activation, and promotes tumor growth. Protein function: G-protein coupled receptor for the bioactive lysosphingolipid sphingosine 1-phosphate (S1P) that seems to be coupled to the G(i) subclass of heteromeric G proteins. Signaling leads to the activation of RAC1, SRC, PTK2/FAK1 and MAP kinases. Plays an important role in cell migration, probably via its role in the reorganization of the actin cytoskeleton and the formation of lamellipodia in response to stimuli that increase the activity of the sphingosine kinase SPHK1. Required for normal chemotaxis toward sphingosine 1-phosphate. Required for normal embryonic heart development and normal cardiac morphogenesis. Plays an important role in the regulation of sprouting angiogenesis and vascular maturation. Inhibits sprouting angiogenesis to prevent excessive sprouting during blood vessel development. Required for normal egress of mature T-cells from the thymus into the blood stream and into peripheral lymphoid organs. Plays a role in the migration of osteoclast precursor cells, the regulation of bone mineralization and bone homeostasis. Plays a role in responses to oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3- phosphocholine by pulmonary endothelial cells and in the protection against ventilator-induced lung injury. [The UniProt Consortium]