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Implementing Patch Clamp and Live Fluorescence Microscopy to Monitor Functional Properties of Freshly Isolated PKD Epithelium
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Divergent function of polycystin 1 and polycystin 2 in cell size regulation

Amandine Viau1, Fruzsina Kotsis2, Christopher Boehlke3

  • 1Renal Department, University Medical Center, Freiburg, Germany; Faculty of Medicine, University of Freiburg, Freiburg, Germany.

Biochemical and Biophysical Research Communications
|November 1, 2019
PubMed

Insights

Polycystin-1 (PC1) uniquely regulates cell size in response to kidney tubule cilia bending, unlike polycystin-2 (PC2). This PC1 function links mechanical signals to cell growth, potentially explaining disease severity differences in autosomal dominant polycystic kidney disease (ADPKD).

Area of Science:

  • Cell Biology
  • Nephrology
  • Genetics

Background:

  • Autosomal dominant polycystic kidney disease (ADPKD) arises from mutations in PKD1 or PKD2, encoding polycystin 1 (PC1) and polycystin 2 (PC2).
  • PC1 and PC2 form a complex within primary cilia, crucial for signaling in renal tubular cells.
  • PKD1 mutations typically present with a more severe phenotype than PKD2 mutations, suggesting distinct PC1 functions.

Purpose of the Study:

  • To investigate divergent molecular functions of PC1 and PC2 in renal tubular cells.
  • To determine the role of PC1 in regulating cell size in response to mechanical stimuli, specifically cilium bending induced by fluid flow.

Main Methods:

  • Employed various in vitro approaches to study polycystin function.
  • Assessed the regulation of cell size under fluid flow conditions.
  • Investigated the coupling mechanism between ciliary mechanical deflection and cellular signaling pathways like mTOR.

Main Results:

  • PC1, but not PC2, was found to regulate tubular cell size under fluid flow, mimicking the effect of cilia loss.
  • PC1 is essential for transducing mechanical signals from ciliary bending to the mTOR pathway.
  • Demonstrated distinct roles for PC1 and PC2 in mechanotransduction within renal tubular cells.

Conclusions:

  • PC1 possesses unique functions in renal tubular cells, particularly in regulating cell size via mechanosensation.
  • The identified divergent functions of PC1 and PC2 provide a molecular basis for differential disease severity in ADPKD.
  • Understanding these distinct polycystin roles offers potential therapeutic targets for ADPKD.

Keywords:
ADPKDCiliaFlowPolycystinsmTOR

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