Wtip- and gadd45a-interacting protein dendrin is not crucial for the development or maintenance of the glomerular filtration barrier

PLoS One. 2013 Dec 20;8(12):e83133. doi: 10.1371/journal.pone.0083133. eCollection 2013.

Abstract

Glomerular podocyte cells are critical for the function of the renal ultrafiltration barrier. Especially, the highly specialized cell-cell junction of podocytes, the slit diaphragm, has a central role in the filtration barrier. This is highlighted by the fact that mutations in molecular components of the slit diaphragm, including nephrin and Cd2-associated protein (Cd2ap), result in proteinuric diseases in man. Dendrin is a poorly characterized cytosolic component of the slit diaphragm in where it interacts with nephrin and Cd2ap. Dendrin is highly specific for the podocyte slit diaphragm, suggesting that it has a dedicated role in the glomerular filtration barrier. In this study, we have generated a dendrin knockout mouse line and explored the molecular interactions of dendrin. Dendrin-deficient mice were viable, fertile, and had a normal life span. Morphologically, the glomerulogenesis proceeded normally and adult dendrin-deficient mice showed normal glomerular histology. No significant proteinuria was observed. Following glomerular injury, lack of dendrin did not affect the severity of the damage or the recovery process. Yeast two-hybrid screen and co-immunoprecipitation experiments showed that dendrin binds to Wt1-interacting protein (Wtip) and growth arrest and DNA-damage-inducible 45 alpha (Gadd45a). Wtip and Gadd45a mediate gene transcription in the nucleus, suggesting that dendrin may have similar functions in podocytes. In line with this, we observed the relocation of dendrin to nucleus in adriamycin nephropathy model. Our results indicate that dendrin is dispensable for the function of the normal glomerular filtration barrier and that dendrin interacts with Wtip and Gadd45a.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Carrier Proteins / genetics*
  • Carrier Proteins / metabolism
  • Cell Cycle Proteins / genetics*
  • Cell Cycle Proteins / metabolism
  • Cell Nucleus / metabolism
  • Co-Repressor Proteins
  • Cytoskeletal Proteins
  • Female
  • Gene Expression Regulation, Developmental*
  • Glomerular Filtration Rate / physiology
  • Kidney Glomerulus / cytology
  • Kidney Glomerulus / growth & development
  • Kidney Glomerulus / metabolism*
  • Male
  • Mice
  • Mice, Knockout
  • Morphogenesis
  • Nerve Tissue Proteins / deficiency
  • Nerve Tissue Proteins / genetics*
  • Nuclear Proteins / genetics*
  • Nuclear Proteins / metabolism
  • Podocytes / cytology
  • Podocytes / metabolism*
  • Protein Binding
  • Protein Transport

Substances

  • Carrier Proteins
  • Cell Cycle Proteins
  • Co-Repressor Proteins
  • Cytoskeletal Proteins
  • Gadd45a protein, mouse
  • Nerve Tissue Proteins
  • Nuclear Proteins
  • Wtip protein, mouse
  • dendrin

Grants and funding

The study was supported by the Knut and Alice Wallenberg Foundation (CB and KT), the Swedish Research Council (CB, KT, and JP), the Swedish Child Diabetes Foundation (JP), and Diabetesfonden (the Diabetes Foundation) (JP). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.