In healthy individuals excess acid generated from metabolism is excreted into the urine by specialised alpha-Intercalated cells (α-IC) of the distal tubule. These cells require the co-ordinated action of several proteins to adequately acidify the urine. One such protein, located at the blood-facing surface (the basolateral membrane) of the α-IC, is kidney anion exchanger 1 (kAE1), a truncated isoform of the red blood cell anion exchanger 1 (eAE1, Band 3). Specific mutations of the AE1 gene cause distal renal tubular acidosis (dRTA) demonstrating its essential role in urine acidification. We are interested in characterising interactions between kAE1 and other proteins that may play a role in regulating kAE1 trafficking or stabilise it at its basolateral membrane location. In the erythrocyte AE1 is known to be a fundamental component of an AE1-Rh membrane protein macrocomplex, which includes the Rhesus associated protein, RhAG. Importantly, the α-IC contains two RhAG homologues, RhBG and RhCG, that are thought to be implicated in acid secretion via ammonia transport. We have created novel RhBG and RhCG cell lines and antibodies to test our hypothesis that a similar RhBG or RhCG:kAE1 complex may exist in the kidney. To independently confirm the location of RhBG and RhCG in the kidney we have created and polarised MDCKI cell lines stably expressing either human RhBG or RhCG tagged with C- or N-terminal GFP in the presence and absence of kAE1. We have shown that choice of location of the GFP tag on RhBG or RhCG can influence the polarised localisation of the proteins. The cell lines, and human kidney tissue, have been used to characterise novel antibodies to RhCG that are now being used to investigate RhCG distribution and putative in vivo kAE1 co-localisation in human and mouse kidney. We are now utilising these novel cell lines to investigate the existence of a putative RhBG or RhCG:kAE1 interaction in the basolateral membrane. This cell model system will also allow for future investigation to define the physiological function of these transporters.