KANK deficiency leads to podocyte dysfunction and nephrotic syndrome

Gee, H.Y., Zhang, F., Ashraf, S., Kohl, S., Sadowski, C.E., Vega-Warner, V., Zhou, W., Lovric, S., Fang, H., Nettleton, M., Zhu, J.Y., Hoefele, J., Weber, L.T., Podracka, L., Boor, A., Fehrenbach, H., Innis, J.W., Washburn, J., Levy, S., Lifton, R.P., Otto, E.A., Han, Z., Hildebrandt, F.
The Journal of Clinical Investigation   125(6): 2375-84 (Journal)
Registered Authors
Zhou, Weibin
MeSH Terms
  • Animals
  • Cell Line
  • Drosophila Proteins/genetics
  • Drosophila Proteins/metabolism
  • Drosophila melanogaster
  • Female
  • Gene Knockdown Techniques
  • Humans
  • Male
  • Microfilament Proteins/genetics
  • Microfilament Proteins/metabolism
  • Mutation*
  • Nephrotic Syndrome*/genetics
  • Nephrotic Syndrome*/metabolism
  • Nephrotic Syndrome*/pathology
  • Podocytes*/metabolism
  • Podocytes*/pathology
  • Proteinuria*/genetics
  • Proteinuria*/metabolism
  • Proteinuria*/pathology
  • Rats
  • Tumor Suppressor Proteins*/deficiency
  • Tumor Suppressor Proteins*/metabolism
  • Zebrafish/genetics
  • Zebrafish/metabolism
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/metabolism
25961457 Full text @ Journal of Clin. Invest.
Steroid-resistant nephrotic syndrome (SRNS) is a frequent cause of progressive renal function decline and affects millions of people. In a recent study, 30% of SRNS cases evaluated were the result of monogenic mutations in 1 of 27 different genes. Here, using homozygosity mapping and whole-exome sequencing, we identified recessive mutations in kidney ankyrin repeat-containing protein 1 (KANK1), KANK2, and KANK4 in individuals with nephrotic syndrome. In an independent functional genetic screen of Drosophila cardiac nephrocytes, which are equivalents of mammalian podocytes, we determined that the Drosophila KANK homolog (dKank) is essential for nephrocyte function. RNAi-mediated knockdown of dKank in nephrocytes disrupted slit diaphragm filtration structures and lacuna channel structures. In rats, KANK1, KANK2, and KANK4 all localized to podocytes in glomeruli, and KANK1 partially colocalized with synaptopodin. Knockdown of kank2 in zebrafish recapitulated a nephrotic syndrome phenotype, resulting in proteinuria and podocyte foot process effacement. In rat glomeruli and cultured human podocytes, KANK2 interacted with ARHGDIA, a known regulator of RHO GTPases in podocytes that is dysfunctional in some types of nephrotic syndrome. Knockdown of KANK2 in cultured podocytes increased active GTP-bound RHOA and decreased migration. Together, these data suggest that KANK family genes play evolutionarily conserved roles in podocyte function, likely through regulating RHO GTPase signaling.
Genes / Markers
Show all Figures
Mutation and Transgenics
Human Disease / Model Data
Sequence Targeting Reagents
Engineered Foreign Genes
Errata and Notes