Adhesion GPCR, AGRA3, is expressed on the apical membrane of the renal DCT2 and CNT

ADGRA3 (GPR125) is an orphan receptor within the adhesion family of G-protein coupled receptors (GPCR). We recently found that ADGRA3 is highly expressed in the whole kidney (via RT-PCR); however, its exact localization and function in the kidney is unknown. To determine its localization, we took advantage of a specific antibody that detects human and mouse ADGRA3 and co-labeled it with known tubule markers. Using murine C57BL6 kidney sections, we determined that ADGRA3 is found on the apical membrane of cortical tubule segments. Robust co-labeling was detected with the calcium transporter Calbindin, which is located in the distal convoluted tubule (DCT) and connecting tubule (CNT). The DCT is divided into the earlier (DCT1) and later (DCT2) portions. To determine the specific localization of ADGRA3 in the DCT, we colocalized ADGRA3 with known DCT markers. Co-labeling was detected with plasma membrane calcium ATPase 1 (PMCA1) which is located in the DCT2 and connecting tubules, whereas no colocalization was observed with Parvalbumin, which is located in the DCT1. Additionally, a subset of tubules were positive for both ADGRA3 and Aquaporin-2 within the cortical collecting duct. No colocalization was detected with the Calcium Sensing Receptor, which is localized primarily in the Loop of Henle. This localization pattern was confirmed in human tissue sections indicating conserved localization across species. Thus, we confirmed that ADGRA3 is specifically expressed within the DCT2, CNT, and minimally within the cortical collecting duct. We have determined that ADGRA3 is self-activated by a tethered agonist. Previous findings have suggested that this GPCR is linked to developmental processes, including planar cell polarity in zebrafish and Wnt signaling. Thus, analysis of DCT2 and CNT-specific processes and renal cell development using an Adgra3 knockout mouse is ongoing. NIH This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.