The catastrophic consequences of autosomal dominant polycystic kidney disease (ADPKD), are caused by two mutated genes working together to cause abnormal cell proliferation that ultimately leads to renal failure. New results published by Jing Zhou and colleagues in Nature Cell Biology unravel how these mutated genes operate. ADPKD is a hereditary affliction of the kidney affecting 1 in 1000 people.
ADPKD is caused by mutation of either the PC1 or the PC2 gene. These are membrane proteins that interact, and may form a signalling receptor and ion channel complex. Several signalling pathways are influenced by the PC1-PC2 complex, but it has remained unclear how mutation of these genes leads to derailed renal epithelial cell proliferation.
The Zhou group now demonstrates that PC2 associates with the important cell cycle and cell differentiation regulatory protein, Id2. This association prevents entry of Id2 into the cell nucleus, where it normally acts on cell cycle genes. PC1 turns out to be essential for the PC2-Id2 interaction, explaining why loss of either PC1 or PC2 leads to unchecked nuclear accumulation, and therefore derailed activation of the growth promoter Id2, in the kidney cells of ADPKD patients. Reduced Id2 expression in cells from a mouse model of ADPKD normalizes cell proliferation, although it remains to be seen if this prevents further kidney disease. Nevertheless, these data suggest that Id2 inhibition is a promising line of therapeutic intervention for this common and severe kidney disease.
Jing Zhou (Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA)
bstract available online.
(C) Nature Cell Biology press release.
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