Proton receptors are G protein-coupled receptors that accept protons as ligands and
function as pH sensors. One of the proton receptors, GPR4, is relatively abundant in the
kidney, but its potential role in acid-base homeostasis is unknown. In this study, we
examined the distribution of GPR4 in the kidney, its function in kidney epithelial cells, and
the effects of its deletion on acid-base homeostasis. We observed GPR4 expression in the
kidney cortex, in the outer and inner medulla, in isolated kidney collecting ducts, and in …