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Claudin-16 and claudin-19 function in the thick ascending limb
Jianghui Hou1, Daniel A Goodenough
1Washington University School of Medicine, Division of Renal Diseases, St Louis, Missouri, USA.
Current Opinion in Nephrology and Hypertension
|July 10, 2010
Summary
Claudin-16 and claudin-19 proteins are essential for magnesium reabsorption in the kidney. Their cooperation forms channels crucial for preventing excessive magnesium loss.
Area of Science:
- Nephrology
- Molecular Biology
- Cell Biology
Background:
- Claudins are key tight junction proteins regulating paracellular transport.
- Magnesium reabsorption in the thick ascending limb (TAL) is critical for renal ion homeostasis.
- Disruptions in magnesium transport can lead to inherited renal disorders.
Purpose of the Study:
- To review recent findings on the physiological roles of claudin-16 and claudin-19.
- To elucidate their function in magnesium reabsorption within the TAL.
- To understand the molecular basis of familial hypomagnesemia with hypercalciuria and nephrocalcinosis.
Main Methods:
- Review of current literature on claudin function in renal tubules.
- Analysis of genetic mutations causing hypomagnesemia.
- Examination of mouse models with genetic alterations in claudin-16/19.
Main Results:
- Mutations in claudin-16 and claudin-19 genes cause familial hypomagnesemia with hypercalciuria and nephrocalcinosis.
- Claudin-16 and claudin-19 are required for cation selectivity in the TAL paracellular pathway.
- Co-assembly of claudin-16 and claudin-19 forms essential cation-selective channels for magnesium reabsorption.
- Loss of either claudin leads to excessive renal magnesium wasting in mice.
Conclusions:
- Claudin oligomeric complexes form epithelial paracellular channels.
- Claudin-16 and claudin-19 cooperate in the mouse TAL to facilitate magnesium reabsorption.
- Understanding claudin roles in nephron segments is vital for renal ion homeostasis.
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