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Calcium channels.

A S Yu
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Abstract

A key step in renal calcium reabsorption is dihydropyridine-sensitive calcium entry across the apical membrane of the distal tubule. Electrophysiologic studies have confirmed the existence of calcium channels that may mediate this pathway. Molecular studies of voltage-dependent calcium channels have revealed a surprising degree of heterogeneity. The pore-forming alpha 1 subunit is encoded by multiple genes, each directing the synthesis of several alternatively spliced transcripts whose products may in turn be posttranslationally cleaved to yield multiple differently-sized peptides. Further heterogeneity is afforded by the presence of accessory subunits, such as the beta subunit, which is also encoded by a multigene family. Site-directed mutagenesis studies of the alpha 1 subunit have begun to explore the molecular structure of the calcium pore. Molecular cloning of rat renal calcium channel transcripts has identified alpha 1 and beta subunit genes that are expressed in the distal tubule. Future studies will address the structure-function relationship of various physiologic properties associated with the channels expressed by these genes.

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AnimalsBiological TransportCalciumCalcium ChannelsCell MembraneHumansKidneyModels, ChemicalMolecular StructureJournal ArticleResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, P.H.S.Review

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A S Yu. 1994. Calcium channels.. https://doi.org/10.1097/00041552-199409000-00004

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