GABARAP deficiency modulates expression of NaPi-IIa in renal brush-border membranes

Sonja C. Reining, Serge M. Gisler, Daniel Fuster, Orson W. Moe, Gregory A. O'Sullivan, Heinrich Betz, Jürg Biber, Heini Murer, Nati Hernando

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

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 GABAA receptor-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+-dependent 32P i uptake 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 Pi content.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Renal Physiology
Volume296
Issue number5
DOIs
StatePublished - May 2009

Fingerprint

Protein Deficiency
GABA-A Receptors
Microvilli
Kidney
Membranes
Proteins
Proximal Kidney Tubule
Two-Hybrid System Techniques
HEK293 Cells
Glutathione Transferase
Parathyroid Hormone
Phosphates
Amino Acids

Keywords

  • Epithelial transport
  • Phosphate homeostasis
  • Renal proximal tubules

ASJC Scopus subject areas

  • Physiology
  • Urology

Cite this

GABARAP deficiency modulates expression of NaPi-IIa in renal brush-border membranes. / Reining, Sonja C.; Gisler, Serge M.; Fuster, Daniel; Moe, Orson W.; O'Sullivan, Gregory A.; Betz, Heinrich; Biber, Jürg; Murer, Heini; Hernando, Nati.

In: American Journal of Physiology - Renal Physiology, Vol. 296, No. 5, 05.2009.

Research output: Contribution to journalArticle

Reining, SC, Gisler, SM, Fuster, D, Moe, OW, O'Sullivan, GA, Betz, H, Biber, J, Murer, H & Hernando, N 2009, 'GABARAP deficiency modulates expression of NaPi-IIa in renal brush-border membranes', American Journal of Physiology - Renal Physiology, vol. 296, no. 5. https://doi.org/10.1152/ajprenal.90492.2008
Reining, Sonja C. ; Gisler, Serge M. ; Fuster, Daniel ; Moe, Orson W. ; O'Sullivan, Gregory A. ; Betz, Heinrich ; Biber, Jürg ; Murer, Heini ; Hernando, Nati. / GABARAP deficiency modulates expression of NaPi-IIa in renal brush-border membranes. In: American Journal of Physiology - Renal Physiology. 2009 ; Vol. 296, No. 5.
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AU - Reining, Sonja C.

AU - Gisler, Serge M.

AU - Fuster, Daniel

AU - Moe, Orson W.

AU - O'Sullivan, Gregory A.

AU - Betz, Heinrich

AU - Biber, Jürg

AU - Murer, Heini

AU - Hernando, Nati

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KW - Phosphate homeostasis

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