Mouse Sphingosine 1 Phosphate Receptor 1 (S1PR1) Protein

Background

S1PR1 is a G protein-coupled receptor that binds sphingosine-1-phosphate (S1P), a bioactive lipid involved in immune regulation, vascular development, and cellular migration. S1PR1 is widely expressed in endothelial cells, lymphocytes, and smooth muscle cells, where it regulates vascular barrier integrity, immune cell trafficking, and angiogenesis. Activation of S1PR1 by S1P triggers signaling pathways involving Gi proteins, leading to activation of PI3K/Akt, MAPK, and Rac, which regulate cell survival, proliferation, and cytoskeletal dynamics. In the immune system, S1PR1 is critical for lymphocyte egress from lymphoid tissues into circulation, making it a key target for immunosuppressive therapies, such as fingolimod, used in treating multiple sclerosis. In the vasculature, S1PR1 maintains endothelial barrier function and regulates vascular permeability. Dysregulation of S1PR1 signaling is associated with inflammatory diseases, cardiovascular disorders, and cancer, where it promotes tumor angiogenesis and immune evasion. Therapeutically, S1PR1 modulators are being developed for autoimmune diseases, inflammatory conditions, and cancer, highlighting its critical role in immune and vascular homeostasis.