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Kidney Week

Abstract: TH-PO737

MAGED2 (Re)wires G-Protein Coupled Receptor Signaling in Renal Collecting Duct Cells

Session Information

Category: Genetic Diseases of the Kidney

  • 1002 Genetic Diseases of the Kidney: Non-Cystic

Authors

  • Bartram, Malte P., University Hospital Cologne, Cologne, Germany
  • Reusch, Björn, University of Cologne Medical Center, Cologne, Germany
  • Schermer, Bernhard, University Hospital Cologne, Cologne, Germany
  • Benzing, Thomas, University Hospital Cologne, Cologne, Germany
  • Beck, Bodo B., University of Cologne Medical Center, Cologne, Germany
  • Rinschen, Markus M., University Hospital Cologne, Cologne, Germany
Background

Recently mutations in MAGED2 were identified as a genetic cause of very severe X-linked polyhydramnios and transient antenatal Bartter syndrome. Since MAGED2 does not code for a transmembrane protein, the molecular mechanisms that contribute to the antenatal Bartter syndrome remain elusive. First results suggest that MAGED2 acts indirectly on ion channels and transporter expression in the kidney tubule system.

Methods

The role of MAGED2 in renal cell culture systems was studied by analyzing the proteome and phospho-proteome after MAGED2 depletion and by analyzing the influence of MAGED2 on vasopressin induced signaling in mouse collecting duct cells using Western Blot, qPCR and proteomic analyses.

Results

We show that MAGED2 ablation in HEK293T cells induced large effects on the phosphoproteome, without affecting protein levels. Since MAGED2 is expressed during development in collecting duct cells of newborn mice, we analyzed the effects of MAGED2 knockdown on vasopressin-dependent signaling in renal collecting duct cells. We found that MAGED2 knockdown altered V2R-induced cAMP-generation kinetics, phosphoproteome rewiring, and blunted phosphorylation on downstream nodes such as phosphorylated CREB. V2R induced ERK inhibition and aquaporin-2 phosphorylation were not affected. Interestingly, these alterations resulted in a marked increase in aquaporin-2 abundance during long-term V2R activation, that was mediated transcriptionally, potentially through the mediator complex.

Conclusion

In conclusion, we show that MAGED2 is a novel modulator of G-protein coupled signaling, that might control important signaling events involved in ion transport and nephron plasticity in the distal nephron. The relevance of these findings needs to be recapitulated in vivo.