Abstract: SA-PO0252
Activation of Disease Mutant Polycystin-1 by Binding of Stalk-Derived Peptide Agonists
Session Information
- Pharmacology
November 08, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Pharmacology (PharmacoKinetics, -Dynamics, -Genomics)
- 2000 Pharmacology (PharmacoKinetics, -Dynamics, -Genomics)
Authors
- Joshi, Keya, The University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, United States
- Magenheimer, Brenda S., The University of Kansas Medical Center, Kansas City, Kansas, United States
- Haldane, Allan, Temple University, Philadelphia, Pennsylvania, United States
- Zhang, Yan, Michigan Technological University, Houghton, Michigan, United States
- Maser, Robin L., The University of Kansas Medical Center, Kansas City, Kansas, United States
- Miao, Yinglong, The University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, North Carolina, United States
Background
Mutation of Polycystin-1 (PC1), protein product of the PKD1 gene, is responsible for 85% of autosomal dominant polycystic kidney disease (ADPKD). PC1 is an atypical G protein-coupled receptor (GPCR) with an autocatalytic GAIN domain that cleaves PC1 into an extracellular N-terminal and a membrane-embedded C-terminal fragment (CTF). Signaling activation of the PC1 CTF is mediated by its short, N-terminal stalk tethered agonist (TA) via a mechanism resembling adhesion GPCRs and involves interactions between the stalk, TOP domain and putative pore loop (PL). ADPKD mutations within the TA inhibit signaling and prevent stalk-TOP and TOP-PL interactions. Synthetic peptides of 7-, 9- or 17- residues in length derived from the PC1 CTF stalk can re-activate signaling by stalkless CTF. Here we tested the ability of TA peptides to rescue signaling by the ADPKD stalk mutant, G3052R, and elucidated TA peptide binding/activation mechanisms.
Methods
HEK293T cells transiently transfected with wild type or mutant PC1 CTF expression constructs and a signaling reporter were treated with or without TA peptides. Three independent Peptide Gaussian accelerated Molecular Dynamics (Pep-GaMD) simulations (500 ns each) were performed on the CTF-G3052R mutant in the presence of TA peptides p9, p17 or p15.
Results
Cell signaling experiments showed rescue of PC1 CTF-G3052R-mediated promoter reporter activity by peptides p9 and p17, and lack of activation by p15. Pep-GaMD simulations revealed multiple low-energy conformations of the simulated systems, including the “Open”/Inactive, “Intermediate” and “Closed”/Active states. Binding of peptide agonists p9 and p17 to the TOP domain of CTF-G3052R induced close TOP-PL interactions, a characteristic feature of the wild-type PC1 CTF signaling activation mechanism. In contrast, p15 was unable to induce a low-energy “Closed” state with the CTF disease mutant.
Conclusion
Pep-GaMD simulation findings were consistent with the experimental cellular signaling data and revealed important structural dynamic insights into the activation rescue mechanism of PC1 ADPKD mutant by stalk-derived TA peptide agonists. These studies will help advance an in-depth understanding of PC1 signaling and facilitate therapeutic design of PC1 agonists for ADPKD treatment.
Funding
- Other NIH Support