Discrete control of TRPV4 channel function in the distal nephron by protein kinases a and C

Mykola Mamenko, Oleg L. Zaika, Nabila Boukelmoune, Jonathan Berrout, Roger G. O'Neil, Oleh Pochynyuk

Research output: Contribution to journalArticle

24 Scopus citations

Abstract

We have recently documented that the Ca2+-permeable TRPV4 channel, which is abundantly expressed in distal nephron cells, mediates cellular Ca2+ responses to elevated luminal flow. In this study, we combined Fura-2-based [Ca2+]i imaging with immunofluorescence microscopy in isolated split-opened distal nephrons of C57BL/6 mice to probe the molecular determinants of TRPV4 activity and subcellular distribution. We found that activation of the PKC pathway with phorbol 12-myristate 13-acetate significantly increased [Ca2+] i responses to flow without affecting the subcellular distribution of TRPV4. Inhibition of PKC with bisindolylmaleimide I diminished cellular responses to elevated flow. In contrast, activation of the PKA pathway with forskolin did not affect TRPV4-mediated [Ca2+]i responses to flow but markedly shifted the subcellular distribution of the channel toward the apical membrane. These actions were blocked with the specific PKA inhibitor H-89. Concomitant activation of the PKA and PKC cascades additively enhanced the amplitude of flow-induced [Ca2+]i responses and greatly increased basal [Ca2+]i levels, indicating constitutive TRPV4 activation. This effect was precluded by the selective TRPV4 antagonist HC-067047. Therefore, the functional status of the TRPV4 channel in the distal nephron is regulated by two distinct signaling pathways. Although the PKA-dependent cascade promotes TRPV4 trafficking and translocation to the apical membrane, the PKC-dependent pathway increases the activity of the channel on the plasma membrane.

Original languageEnglish (US)
Pages (from-to)20306-20314
Number of pages9
JournalJournal of Biological Chemistry
Volume288
Issue number28
DOIs
StatePublished - Jul 12 2013
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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