LPA5 (GPR92) represents a putative orphan G protein coupled receptor with unknown functions. The mouse LPA5 receptor gene has an 81% homology to the human ortholog. Research has shown LPA5 to be expressed in the mouse intestine and upon stimulation with LPA, activates Na+/H+ exchanger 3 and stimulates sodium and fluid absorption. ESTs for LPA5 have been isolated from human normal brain, testis, and tonsil B-cell libraries and from a human blood cancer cell library (pre-B cell). LPA5 protein contains 372 amino acids and shared 36 to 40% sequence identity in the transmembrane regions with the G protein-coupled purinergic receptor P2Y5 (P2RY5), GPR23, and GPR17.