Recombinant Human GPR15L protein

**Background of GPR15L Recombinant Protein**

GPR15L (G Protein-Coupled Receptor 15 Ligand) is a recently identified protein that serves as the endogenous ligand for the orphan receptor GPR15. a class A G protein-coupled receptor (GPCR). Initially discovered through bioinformatic and functional screening approaches, GPR15L is encoded by the *C10orf99* gene in humans and shares structural homology with prokineticin family proteins, though it lacks their conserved N-terminal sequence. This secreted glycoprotein plays a critical role in regulating immune responses, particularly in T-cell trafficking and tissue-specific homing.

GPR15L binds to GPR15. which is highly expressed in immune cells, including regulatory T cells (Tregs) and effector lymphocytes, as well as in epithelial and mucosal tissues. The GPR15L-GPR15 axis is implicated in mucosal immunity, inflammation, and immune tolerance. For instance, it facilitates the homing of T cells to the colon, influencing inflammatory bowel disease (IBD) pathogenesis, and modulates skin immune responses. Dysregulation of this pathway has been linked to autoimmune disorders and cancer progression.

Recombinant GPR15L is produced using engineered host systems (e.g., mammalian cells or *E. coli*) to ensure proper post-translational modifications and bioactivity. It is purified via affinity chromatography, often with tags for enhanced stability. This protein is widely used in vitro and in vivo to study receptor-ligand interactions, signaling mechanisms (e.g., cAMP or MAPK pathways), and therapeutic targeting. Its applications extend to drug discovery for autoimmune diseases, colitis, and cancer immunotherapy.

Current research focuses on elucidating its structural determinants, tissue-specific functions, and potential as a biomarker or therapeutic target, highlighting its emerging significance in immunology and translational medicine.