OXER1 is a G protein-coupled receptor primarily activated by the eicosanoid metabolite 5-oxo-ETE and related polyunsaturated fatty acids 1. The receptor couples to Gi/Go heteromeric G proteins and mediates diverse physiological functions across multiple tissue systems 1. In immune responses, OXER1 functions as a potent leukocyte chemoattractant 2. The 5-oxo-ETE/OXER1 axis is essential for early antimicrobial defense, with OXER1 deletion in zebrafish attenuating neutrophil recruitment and decreasing post-infection survival 2. Beyond immunity, OXER1 serves as a tissue redox sensor that protects intestinal epithelial barriers against oxidative stress by inducing DNA-protective Nudix hydrolases 3. In endocrine tissues, OXER1 activation enhances steroid production in adrenocortical and Leydig cells through ERK1/2 phosphorylation and StAR protein induction 1. OXER1 additionally functions as a membrane androgen receptor in cancer cells 4, where testosterone competes for 5-oxo-ETE binding and antagonizes its signaling 5. OXER1 is upregulated in cancer cell migration, with 5-oxo-ETE promoting epithelial cell migration through Gβγ-mediated actin cytoskeletal reorganization 6. In tumor microenvironments, the 5-oxo-ETE/OXER1 axis mediates macrophage recruitment and enhances cancer cell motility 7.