Author(s): Chen XZ, Vassilev PM, Basora N, Peng JB, Nomura H,
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Abstract Polycystic kidney diseases are genetic disorders in which the renal parenchyma is progressively replaced by fluid-filled cysts. Two members of the polycystin family (polycystin-1 and -2) are mutated in autosomal dominant polycystic kidney disease (ADPKD), and polycystin-L is deleted in mice with renal and retinal defects. Polycystins are membrane proteins that share significant sequence homology, especially polycystin-2 and -L (50\% identity and 71\% similarity). The functions of the polycystins remain unknown. Here we show that polycystin-L is a calcium-modulated nonselective cation channel that is permeable to sodium, potassium and calcium ions. Patch-clamp experiments revealed single-channel activity with a unitary conductance of 137 pS. Channel activity was substantially increased when either the extracellular or intracellular calcium-ion concentration was raised, indicating that polycystin-L may act as a transducer of calcium-mediated signalling in vivo. Its large single-channel conductance and regulation by calcium ions distinguish it from other structurally related cation channels.
This article was published in Nature
and referenced in Biochemistry & Physiology: Open Access