GABARAP deficiency modulates expression of NaPi-IIa in renal brush-border membranes
| Autor: | Heinrich Betz, Orson W. Moe, Gregory A. O'Sullivan, Sonja C. Reining, Serge M. Gisler, Heini Murer, Jürg Biber, Daniel Guido Fuster, Nati Hernando |
|---|---|
| Přispěvatelé: | University of Zurich, Hernando, N |
| Rok vydání: | 2009 |
| Předmět: |
2748 Urology
medicine.medical_specialty Sodium-Hydrogen Exchangers Brush border Physiology GABARAP Gene Expression Parathyroid hormone Biology Kidney Sodium-Phosphate Cotransporter Proteins Type IIa Cell Line Phosphates 10052 Institute of Physiology Kidney Tubules Proximal Mice Internal medicine medicine Animals Homeostasis Humans RNA Messenger 610 Medicine & health Embryonic Stem Cells Gene Library Microvilli Membrane Proteins Renal Reabsorption Epithelial Cells Articles 1314 Physiology Phosphoproteins Endocytosis Mice Mutant Strains Cytoskeletal Proteins Sodium–hydrogen antiporter medicine.anatomical_structure Endocrinology Membrane protein Parathyroid Hormone Phosphorus Dietary 570 Life sciences biology Apoptosis Regulatory Proteins Microtubule-Associated Proteins |
| Zdroj: | American Journal of Physiology-Renal Physiology. 296:F1118-F1128 |
| ISSN: | 1522-1466 1931-857X |
| Popis: | Renal reabsorption of inorganic phosphate (Pi) is mainly mediated by the Na+-dependent Pi-cotransporter NaPi-IIa that is expressed in the brush-border membrane (BBM) of renal proximal tubules. Regulation and apical expression of NaPi-IIa are known to depend on a network of interacting proteins. Most of the interacting partners identified so far associate with the COOH-terminal PDZ-binding motif (TRL) of NaPi-IIa. In this study GABAAreceptor-associated protein (GABARAP) was identified as a novel interacting partner of NaPi-IIa applying a membrane yeast-two-hybrid system (MYTH 2.0) to screen a mouse kidney library with the TRL-truncated cotransporter as bait. GABARAP mRNA and protein are present in renal tubules, and the interaction of NaPi-IIa and GABARAP was confirmed by using glutathione S-transferase pulldowns from BBM and coimmunoprecipitations from transfected HEK293 cells. Amino acids 36–68 of GABARAP were identified as the determinant for the described interaction. The in vivo effects of this interaction were studied in a murine model. GABARAP−/−mice have reduced urinary excretion of Pi, higher Na+-dependent32Piuptake in BBM vesicles, and increased expression of NaPi-IIa in renal BBM compared with GABARAP+/+mice. The expression of Na+/H+exchanger regulatory factor (NHERF)1, an important scaffold for the apical expression of NaPi-IIa, is also increased in GABARAP−/−mice. The absence of GABARAP does not interfere with the regulation of the cotransporter by either parathyroid hormone or acute changes of dietary Picontent. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|