Reduced nephrin tyrosine phosphorylation impairs podocyte force transmission and accelerates detachment in disease

Casey R Williamson; Claire E Martin; J Dinesh Kumar; Peihua Lu; Laura A New; Alice Y Wang; Nils M Kronenberg; Malte C Gather; Paul A Reynolds; Nina Jones

doi:10.1016/j.isci.2025.112673

Reduced nephrin tyrosine phosphorylation impairs podocyte force transmission and accelerates detachment in disease

iScience. 2025 May 14;28(6):112673. doi: 10.1016/j.isci.2025.112673. eCollection 2025 Jun 20.

Authors

Casey R Williamson¹, Claire E Martin¹, J Dinesh Kumar^{2

3}, Peihua Lu¹, Laura A New¹, Alice Y Wang¹, Nils M Kronenberg^{2

3

4}, Malte C Gather^{2

3

4

5}, Paul A Reynolds^{3

6}, Nina Jones¹

Affiliations

¹ Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada.
² SUPA, School of Physics and Astronomy, University of St. Andrews, KY16 9SS St. Andrews, UK.
³ Biomedical Sciences Research Complex, University of St. Andrews, KY16 9ST St. Andrews, UK.
⁴ Department of Chemistry, Humboldt Centre for Nano- and Biophotonics, University of Cologne, 50939 Cologne, Germany.
⁵ Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Disease (CECAD), University of Cologne, 50931 Cologne, Germany.
⁶ School of Medicine, University of St. Andrews, KY16 9TF St. Andrews, UK.

Abstract

Podocytes are specialized kidney cells that form the slit diaphragm (SD), an intercellular filtration barrier against plasma protein loss. The SD is subject to significant mechanical strain which can be amplified in disease, leading to podocyte detachment. One key SD protein that might intercept mechanical strain and transmit adhesion signals is nephrin, although its influence on podocyte force transmission remains uncharacterized. Using immunoblotting and elastic resonator interference stress microscopy (ERISM), we demonstrate that nephrin clustering induces rapid podocyte force transmission and adhesion protein activation (paxillin, FAK, and p130Cas), which require nephrin tyrosine phosphorylation at its three YDxV motifs. Furthermore, using a model of diabetic nephropathy to amplify mechanical stress in vivo, we show that abolishing phosphorylation at YDxV tyrosines leads to exacerbated proteinuria, glomerular hypertrophy, and podocyte detachment. Altogether, this study links nephrin phosphorylation with force transmission, which is likely critical to maintaining podocyte adhesion during many renal pathologies.

Keywords: Biochemistry; Biomechanics; Cell biology; Specialized functions of cells.