S1PR4 (Sphingosine-1-Phosphate Receptor 4): S1PR4 is a G protein-coupled receptor for sphingosine-1-phosphate (S1P), a lipid signaling molecule that influences immune cell migration, angiogenesis, and endothelial barrier integrity. S1PR4 is predominantly expressed in hematopoietic cells and plays a role in regulating immune responses and inflammation. Alterations in S1PR4 signaling can contribute to immune disorders and inflammatory diseases, emphasizing its role in immune regulation and inflammation....