Cloning and expression of a novel truncated calcium channel from non-excitable cells.
Calcium entry, via a dihydropyridine-sensitive pathway, is required for differentiation in murine erythroleukemia cells (MELC). Calcium channel currents have been identified physiologically in some non-excitable cells, but little is known regarding the structure of these channels. We show that a truncated form of the alpha 1 subunit of the cardiac voltage-gated calcium channel (dihydropyridine receptor, DHPR) is expressed in MELC. This MELC calcium channel lacks the first four transmembrane segments of the DHPR (IS1 to IS4). A MELC calcium channel/cardiac DHPR chimera, co-expressed with the alpha 2 and beta subunits of the DHPR, forms a functional calcium channel in Xenopus oocytes.
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Department of Medicine, Mount Sinai School of Medicine, New York, New York 10029.
Kobrinsky
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D000081:Acetamides / Q000494:pharmacology; D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D015220:Calcium Channels / Q000235:genetics* / Q000378:metabolism; D020746:Calcium Channels, L-Type; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D003001:Cloning, Molecular; D018076:DNA, Complementary; D004095:Dihydropyridines / Q000378:metabolism; D004915:Leukemia, Erythroblastic, Acute / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009124:Muscle Proteins / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014407:Tumor Cells, Cultured; D014982:Xenopus laevis
D000081:Acetamides; D015220:Calcium Channels; D020746:Calcium Channels, L-Type; D018076:DNA, Complementary; D004095:Dihydropyridines; D009124:Muscle Proteins; D012333:RNA, Messenger; C038806:1,4-dihydropyridine; C014026:hexamethylene bisacetamide