Progesterone down-regulates the open probability of the amiloride-sensitive epithelial sodium channel via a Nedd4-2-dependent mechanism
- Michlig, Stéphanie Département de Pharmacologie et de Toxicologie, Université de Lausanne, Switzerland
- Harris, Michael Département de Pharmacologie et de Toxicologie, Université de Lausanne, Switzerland
- Loffing, Johannes Département de Médicine, Unité d'Anatomie, Université de Fribourg, Switzerland
- Rossier, Bernard C. Département de Pharmacologie et de Toxicologie, Université de Lausanne, Switzerland
- Firsov, Dmitri Département de Pharmacologie et de Toxicologie, Université de Lausanne, Switzerland
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19.09.2005
Published in:
- Journal of Biological Chemistry. - 2005, vol. 280, no. 46, p. 38264-38270
English
Activation of the mitogen-activated protein (MAP) kinase cascade by progesterone in Xenopus oocytes leads to a marked down-regulation of activity of the amiloride-sensitive epithelial sodium channel (ENaC). Here we have studied the signaling pathways involved in progesterone effect on ENaC activity. We demonstrate that: (i) the truncation of the C termini of the αβγENaC subunits results in the loss of the progesterone effect on ENaC; (ii) the effect of progesterone was also suppressed by mutating conserved tyrosine residues in the Pro-X-X-Tyr (PY) motif of the C termini of the βand γ ENaC subunits (βY618A and γY628A); (iii) the down-regulation of ENaC activity by progesterone was also suppressed by co-expression ENaC subunits with a catalytically inactive mutant of Nedd4-2, a ubiquitin ligase that has been previously demonstrated to decrease ENaC cell-surface expression via a ubiquitin-dependent internalization/degradation mechanism; (iv) the effect of progesterone was significantly reduced by suppression of consensus sites (βT613A and γT623A) for ENaC phosphorylation by the extracellular-regulated kinase (ERK), a MAP kinase previously shown to facilitate the binding of Nedd4 ubiquitin ligases to ENaC; (v) the quantification of cell-surface-expressed ENaC subunits revealed that progesterone decreases ENaC open probability (whole cell Po, wcP o) and not its cell-surface expression. Collectively, these results demonstrate that the binding of active Nedd4-2 to ENaC is a crucial step in the mechanism of ENaC inhibition by progesterone. Upon activation of ERK, the effect of Nedd4-2 on ENaC open probability can become more important than its effect on ENaC cell-surface expression.
- Faculty
- Faculté des sciences et de médecine
- Department
- Département de Médecine
- Language
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- English
- Classification
- Biology
- License
- License undefined
- Identifiers
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- RERO DOC 5440
- DOI 10.1074/jbc.M506308200
- Persistent URL
- https://folia.unifr.ch/unifr/documents/299883
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