OXGR1 (2-oxoglutarate receptor 1), also known as GPR99. is a class A G protein-coupled receptor (GPCR) that belongs to the α-ketoglutarate receptor family. It was initially identified as an orphan receptor until studies revealed its activation by α-ketoglutarate (α-KG), a tricarboxylic acid cycle intermediate, and other oxocarboxylic acids like succinate and fumarate. Structurally, OXGR1 contains seven transmembrane domains and signals primarily through Gq/11 proteins, leading to intracellular calcium mobilization. This receptor is expressed in various tissues, including the kidney, ovary, spleen, and immune cells, suggesting roles in pH homeostasis, inflammation, and cellular metabolism.
Antibodies targeting OXGR1/GPR99 are critical tools for studying its expression, localization, and function. They enable detection in complex biological samples via techniques like Western blotting, immunohistochemistry, and flow cytometry. Research using these antibodies has linked OXGR1 to renal tubular acidosis, asthma, and tumor microenvironment regulation. For instance, in the kidney, OXGR1 modulates bicarbonate transport, while in immune cells, it may influence inflammatory responses. Recent studies also explore its potential as a therapeutic target in metabolic disorders and cancer. However, challenges remain in characterizing its precise signaling mechanisms and ligand specificity, necessitating validated antibodies to minimize cross-reactivity with related GPCRs. Overall, OXGR1 antibodies advance understanding of its physiological and pathological roles, bridging gaps between receptor biology and disease intervention strategies.