Abstract: FR-PO0090
Defining Regulators of PC2 Ciliary Trafficking Using Endogenous Pkd2-HaloTag Models
Session Information
- ADPKD and Cystic Kidney Disease - 2
October 23, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Genetic Diseases of the Kidneys
- 1201 Genetic Diseases of the Kidneys: Cystic (Monogenic)
Authors
- Li, Zhang, The University of Alabama at Birmingham Heersink School of Medicine, Birmingham, Alabama, United States
- Haycraft, Courtney J., The University of Alabama at Birmingham Heersink School of Medicine, Birmingham, Alabama, United States
- Croyle, Mandy J., The University of Alabama at Birmingham Heersink School of Medicine, Birmingham, Alabama, United States
- Yoder, Bradley K., The University of Alabama at Birmingham Heersink School of Medicine, Birmingham, Alabama, United States
Background
Mutations in PKD1 or PKD2, encoding polycystin-1(PC1) and polycystin-2 (PC2), account for most cases of Autosomal Dominant Polycystic Kidney Disease. Although the polycystin complex functions at primary cilia, the mechanisms that deliver PC2 to cilia and maintain its ciliary pool remain incompletely defined. We recently developed an endogenous Pkd2-HaloTag knock-in mouse and derived renal epithelial cell models, providing a platform to visualize and biochemically isolate endogenous PC2. Here, we used these models to identify regulators of PC2 ciliary trafficking.
Methods
To determine whether PC1 or TULP3 is required for PC2 ciliary localization in vivo, Pkd2-HaloTag mice were crossed with Pkd1 or Tulp3 mutant backgrounds, followed by HaloTag ligand labeling and analysis of PC2-Halo localization in kidney tissue. In parallel, we generated Pkd1- and Tulp3-knockout Pkd2-HaloTag renal epithelial cell lines using CRISPR/Cas9. To identify additional regulators of PC2 trafficking, we performed comparative mass spectrometry on HaloTag affinity-purified PC2 complexes from cell lines that are either competent (WT) or defective (Pkd1 or Tulp3 KO) for PC2 ciliary localization.
Results
Loss of either PC1 or TULP3 disrupted ciliary localization of endogenous PC2-Halo in kidney tissue and in established renal epithelial cell lines. Comparative mass spectrometry of HaloTag pulldowns identified candidate PC2-associated trafficking regulators, including CEP290 and other known ciliary trafficking proteins. CEP290 and additional candidates are being functionally tested using CRISPR-based perturbation in Pkd2-HaloTag cell models to determine their requirement for PC2 ciliary targeting.
Conclusion
These studies establish endogenous Pkd2-HaloTag mouse and cell models as powerful platforms for analyzing PC2 trafficking in vivo and in vitro. Our data support essential roles for PC1 and TULP3 in PC2 ciliary localization. Identifying additional regulators of PC2 trafficking will help define the mechanisms that deliver and maintain PC2 within primary cilia, providing new insight into how disrupted polycystin trafficking contributes to cyst initiation in ADPKD.
Funding
- NIDDK Support