Journal Article

Colocalization of the (Pro)renin Receptor/Atp6ap2 with H+-ATPases in Mouse Kidney but Prorenin Does Not Acutely Regulate Intercalated Cell H+-ATPase Activity

Gomes Moreira, Ana, Bourgeois, Soline, Danser, A. H. Jan, Figueiredo, Marta F. L., Daryadel, Arezoo, Oberli, Lisa, Lu, Xifeng, Meima, Marcel E., Mohebbi, Nilufar, Kampik, Nicole B., Wagner, Carsten A.

2016

Overview

The (Pro)renin receptor (P)RR/Atp6ap2 is a cell surface protein capable of binding and non-proteolytically activate prorenin. Additionally, (P)RR is associated with H(+)-ATPases and alternative functions in H(+)-ATPase regulation as well as in Wnt signalling have been reported. Kidneys express very high levels of H(+)-ATPases which are involved in multiple functions such as endocytosis, membrane protein recycling as well as urinary acidification, bicarbonate reabsorption, and salt absorption. Here, we wanted to localize the (P)RR/Atp6ap2 along the murine nephron, exmaine whether the (P)RR/Atp6ap2 is coregulated with other H(+)-ATPase subunits, and whether acute stimulation of the (P)RR/Atp6ap2 with prorenin regulates H(+)-ATPase activity in intercalated cells in freshly isolated collecting ducts. We localized (P)PR/Atp6ap2 along the murine nephron by qPCR and immunohistochemistry. (P)RR/Atp6ap2 mRNA was detected in all nephron segments with highest levels in the collecting system coinciding with H(+)-ATPases. Further experiments demonstrated expression at the brush border membrane of proximal tubules and in all types of intercalated cells colocalizing with H(+)-ATPases. In mice treated with NH4Cl, NaHCO3, KHCO3, NaCl, or the mineralocorticoid DOCA for 7 days, (P)RR/Atp6ap2 and H(+)-ATPase subunits were regulated but not co-regulated at protein and mRNA levels. Immunolocalization in kidneys from control, NH4Cl or NaHCO3 treated mice demonstrated always colocalization of PRR/Atp6ap2 with H(+)-ATPase subunits at the brush border membrane of proximal tubules, the apical pole of type A intercalated cells, and at basolateral and/or apical membranes of non-type A intercalated cells. Microperfusion of isolated cortical collecting ducts and luminal application of prorenin did not acutely stimulate H(+)-ATPase activity. However, incubation of isolated collecting ducts with prorenin non-significantly increased ERK1/2 phosphorylation. Our results suggest that the PRR/Atp6ap2 may form a complex with H(+)-ATPases in proximal tubule and intercalated cells but that prorenin has no acute effect on H(+)-ATPase activity in intercalated cells.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Acidification / Adenosine triphosphatase / Ammonium Chloride - pharmacology / Animals / Anion Transport Proteins - genetics / Anion Transport Proteins - metabolism / Aquaporin 2 - genetics / Aquaporin 2 - metabolism / Bicarbonates / Biology and Life Sciences / Carbonates / Cell Membrane - drug effects / Cell Membrane - metabolism / Cell surface / Dogs / Drinking water / Endocytosis / Experiments / Gene Expression Regulation / H+-transporting ATPase / Hydrogen / Hypertension / Immunohistochemistry / Internal medicine / Kidney Cortex - cytology / Kidney Cortex - drug effects / Kidney Cortex - metabolism / Kidney Medulla - cytology / Kidney Medulla - drug effects / Kidney Medulla - metabolism / Kidney Tubules, Collecting - cytology / Kidney Tubules, Collecting - drug effects / Kidney Tubules, Collecting - metabolism / Kidney Tubules, Proximal - cytology / Kidney Tubules, Proximal - drug effects / Kidney Tubules, Proximal - metabolism / Kidneys / Kinases / Localization / Madin Darby Canine Kidney Cells / Male / Medicine / Medicine and Health Sciences / Membrane Glycoproteins - genetics / Membrane Glycoproteins - metabolism / Membrane proteins / Membranes / Metabolism / Mice / Mice, Inbred C57BL / mRNA / Pharmacology / Phosphorylation / Physiology / Plasma / Protein turnover / Proteins / Proton-Translocating ATPases - genetics / Proton-Translocating ATPases - metabolism / Proximal tubules / Reabsorption / Receptors, Cell Surface - genetics / Receptors, Cell Surface - metabolism / Renin / Renin - pharmacology / Renin-Angiotensin System - drug effects / Research and Analysis Methods / Rodents / Salts / Signal Transduction / Signaling / Sodium Bicarbonate - pharmacology / Sodium chloride / Sodium Chloride - pharmacology / Sodium-Phosphate Cotransporter Proteins, Type IIa - genetics / Sodium-Phosphate Cotransporter Proteins, Type IIa - metabolism / Solute Carrier Family 12, Member 1 - genetics / Solute Carrier Family 12, Member 1 - metabolism / Solute Carrier Family 12, Member 3 - genetics / Solute Carrier Family 12, Member 3 - metabolism / Sulfate Transporters / Wnt protein