Abstract: TH-PO560

Angiomotin Is a Novel Interaction Partner of the Polycystin-1 C-Terminal Tail

Session Information

Category: Genetic Diseases of the Kidney

  • 801 Cystic Kidney Diseases

Authors

  • Mistry, Kavita, Yale University School of Medicine, New Haven, Connecticut, United States
  • Gresko, Nikolay P., Yale University School of Medicine, New Haven, Connecticut, United States
  • Caplan, Michael J., Yale University School of Medicine, New Haven, Connecticut, United States
Background

Autosomal dominant polycystic kidney disease (ADPKD) is the fourth leading cause of adult end-stage renal disease. The majority of ADPKD cases are caused by mutations in the PKD1 gene, which codes for the membrane protein polycystin-1 (pc1). Pc1 is thought to play both direct and indirect roles in modulating gene expression; specifically, portions of the C- terminal tail of pc1, including a ~200 residue fragment ("p200"), are cleaved and may translocate to the nucleus, where they are hypothesized to regulate gene transcription. Previous work in our lab has focused on the transcriptional co-activator TAZ, and demonstrated that p200 stimulates the transcription of TAZ-target genes.

Methods

Using a mass spectrometry-based approach in HEK cells, we have identified angiomotin (AMOT) and Merlin (NF2) as novel interaction partners of the polycystin-1 C-terminal tail. AMOT and NF2 are critical upstream regulators of the Hippo pathway, and they exert their effects via direct binding to the downstream transcriptional co-activators YAP and TAZ, as well as to the inhibitory upstream Hippo kinases.

Results

We have shown using co-immunoprecipitation that AMOT and p200 interact with each other in the nucleus, and that deletion of the p200 nuclear localization sequence, which prevents nuclear trafficking of p200, abrogates the p200-AMOT interaction. In addition, we have shown using CRISPR/Cas9 knockout that AMOT is involved in the biochemical interaction between p200 and TAZ. Furthermore, the expression of several putative transcriptional targets of p200 is altered in AMOT knockout HEK cells. We have shown using co-immunoprecipitation that NF2 and p200 interact, and that NF2 phosphorylation status is altered in the setting of p200 overexpression.

Conclusion

In summary, our data show that the C-terminal tail of pc1 binds to AMOT and NF2, forming a nuclear protein complex that may facilitate target gene transcription.

Funding

  • NIDDK Support