A polycystin-2 protein with modified channel properties leads to an increased diameter of renal tubules and to renal cysts.

Journal of cell science 2021 Aug 15

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Mutations in the PKD2 gene cause autosomal-dominant polycystic kidney disease but the physiological role of polycystin-2, the protein product of PKD2, remains elusive. Polycystin-2 belongs to the transient receptor potential (TRP) family of non-selective cation channels. To test the hypothesis that altered ion channel properties of polycystin-2 compromise its putative role in a control circuit controlling lumen formation of renal tubular structures, we generated a mouse model in which we exchanged the pore loop of polycystin-2 with that of the closely related cation channel polycystin-2L1 (encoded by PKD2L1), thereby creating the protein polycystin-2poreL1. Functional characterization of this mutant channel in Xenopus laevis oocytes demonstrated that its electrophysiological properties differed from those of polycystin-2 and instead resembled the properties of polycystin-2L1, in particular regarding its permeability for Ca2+ ions. Homology modeling of the ion translocation pathway of polycystin-2poreL1 argues for a wider pore in polycystin-2poreL1 than in polycystin-2. In Pkd2poreL1 knock-in mice in which the endogenous polycystin-2 protein was replaced by polycystin-2poreL1 the diameter of collecting ducts was increased and collecting duct cysts developed in a strain-dependent fashion. © 2021. Published by The Company of Biologists Ltd.

Citation

Melanie Grosch, Katrin Brunner, Alexandr V Ilyaskin, Michael Schober, Tobias Staudner, Denise Schmied, Tina Stumpp, Kerstin N Schmidt, M Gregor Madej, Thaissa D Pessoa, Helga Othmen, Marion Kubitza, Larissa Osten, Uwe de Vries, Magdalena M Mair, Stefan Somlo, Markus Moser, Karl Kunzelmann, Christine Ziegler, Silke Haerteis, Christoph Korbmacher, Ralph Witzgall. A polycystin-2 protein with modified channel properties leads to an increased diameter of renal tubules and to renal cysts. Journal of cell science. 2021 Aug 15;134(16)