Acute regulation of renal Na +/H + exchanger NHE3 by dopamine: Role of protein phosphatase 2A

Ion A Bobulescu, Henry Quinones, Serge M. Gisler, Francesca Di Sole, Ming C Hu, Mingjun Shi, Jianning Zhang, Daniel G. Fuster, Nancy Wright, Marc Mumby, Orson W Moe

Research output: Contribution to journalArticle

21 Scopus citations

Abstract

Nephrogenic dopamine is a potent natriuretic paracrine/autocrine hormone that is central for mammalian sodium homeostasis. In the renal proximal tubule, dopamine induces natriuresis partly via inhibition of the sodium/ proton exchanger NHE3. The signal transduction pathways and mechanisms by which dopamine inhibits NHE3 are complex and incompletely understood. This manuscript describes the role of the serine/ threonine protein phosphatase 2A (PP2A) in the regulation of NHE3 by dopamine. The PP2A regulatory subunit B56δ (coded by the Ppp2r5d gene) directly associates with more than one region of the carboxy-terminal hydrophilic putative cytoplasmic domain of NHE3 (NHE3-cyto), as demonstrated by yeast-two-hybrid, coimmunoprecipitation, blot overlay, and in vitro pull-down assays. Phosphorylated NHE3-cyto is a substrate for purified PP2A in an in vitro dephosphorylation reaction. In cultured renal cells, inhibition of PP2A by either okadaic acid or by overexpression of the simian virus 40 (SV40) small T antigen blocks the ability of dopamine to inhibit NHE3 activity and to reduce surface NHE3 protein. Dopamine-induced NHE3 redistribution is also blocked by okadaic acid ex vivo in rat kidney cortical slices. These studies demonstrate that PP2A is an integral and critical participant in the signal transduction pathway between dopamine receptor activation and NHE3 inhibition.

Original languageEnglish (US)
Pages (from-to)F1205-F1213
JournalAmerican Journal of Physiology - Renal Physiology
Volume298
Issue number5
DOIs
StatePublished - May 1 2010

Keywords

  • Natriuresis
  • Signal transduction
  • Sodium transport

ASJC Scopus subject areas

  • Physiology
  • Urology

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