Molecular dysregulation of ciliary polycystin-2 channels caused by variants in the TOP domain
Abstract
Genetic variants in PKD2 which encodes for the polycystin-2 ion channel are responsible for many clinical cases of autosomal dominant polycystic kidney disease (ADPKD). Despite our strong understanding of the genetic basis of ADPKD, we do not know how most variants impact channel function. Polycystin-2 is found in organelle membranes, including the primary cilium—an antennae-like structure on the luminal side of the collecting duct. In this study, we focus on the structural and mechanistic regulation of polycystin-2 by its TOP domain—a site with unknown function that is commonly altered by missense variants. We use direct cilia electrophysiology, cryogenic electron microscopy, and superresolution imaging to determine that variants of the TOP domain finger 1 motif destabilizes the channel structure and impairs channel opening without altering cilia localization and channel assembly. Our findings support the channelopathy classification of PKD2 variants associated with ADPKD, where polycystin-2 channel dysregulation in the primary cilia may contribute to cystogenesis.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Apr 24, 2020
- Source ID
- 10.1073/pnas.1920777117
Entities
People
- Erhu Cao
- Jinliang Wang
- Leo C T Ng
- Paul G. DeCaen
- Thuy N. Vien
Organizations
- ASN Foundation for Kidney Research
- National Institute of Diabetes and Digestive and Kidney Diseases
- Northwestern University
- The Pew Charitable Trusts
- United States Department of Defense
- University of Utah