Ion-channel blocker sensitivity of voltage-gated calcium-channel homologue Cch1 in Saccharomyces cerevisiae

• Published in: Microbiology (Society for General Microbiology) Vol. 154; no. 12; pp. 3775 - 3781
• Main Authors: Teng, Jinfeng, Goto, Rika, Iida, Kazuko, Kojima, Itaru, Iida, Hidetoshi
• Format: Journal Article
• Language: English
• Published: Reading Soc General Microbiol 01.12.2008; Society for General Microbiology
• Subjects: Action of physical and chemical agents; Amino Acid Sequence; Animals; Biological and medical sciences; Calcium - metabolism; Calcium Channel Blockers - pharmacology; Calcium Channels - drug effects; Calcium Channels - genetics; Calcium Channels - metabolism; Calcium Channels, L-Type - drug effects; Calcium Channels, L-Type - genetics; Calcium Channels, L-Type - metabolism; Diltiazem - pharmacology; Fundamental and applied biological sciences. Psychology; Humans; Kinetics; Membrane Glycoproteins - drug effects; Membrane Glycoproteins - genetics; Membrane Glycoproteins - metabolism; Microbiology; Molecular Sequence Data; Mutation; Mycology; Nifedipine - pharmacology; Saccharomyces cerevisiae; Saccharomyces cerevisiae - drug effects; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - growth & development; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae Proteins - drug effects; Saccharomyces cerevisiae Proteins - genetics; Saccharomyces cerevisiae Proteins - metabolism; Up-Regulation; Verapamil - pharmacology; Ascomycota; Fungi; Blocking; Sensitivity; Ionic channel; Saccharomyces cerevisiae
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/mic.0.2008/021089-0

1 Department of Biology, Tokyo Gakugei University, 4-1-1 Nukui kita-machi, Koganei-shi, Tokyo 184-8501, Japan 2 Laboratory of Cell Biology, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma 371-8510, Japan 3 Biomembrane Signaling Project 2, Tokyo Metropolitan Institute of Medical Science, 3-18-22 Honkomagome, Bunkyo-ku, Tokyo 113-8613, Japan 4 Department of Bioenvironmental Science, Okazaki Institute for Integrative Bioscience, National Institutes of Natural Sciences, Higashiyama 5-1, Myodaiji, Okazaki, Aichi 444-8787, Japan Correspondence Hidetoshi Iida iida{at}u-gakugei.ac.jp The Cch1 protein of the yeast Saccharomyces cerevisiae is a homologue of the pore-forming 1 subunit of mammalian voltage-gated Ca 2+ channels (VGCCs), and it constitutes a high-affinity Ca 2+ -influx system with the Mid1 protein in this organism. Here, we characterized the kinetic property of a putative Cch1–Mid1 Ca 2+ channel overexpressed in S. cerevisiae cells, and showed that the L-type VGCC blockers nifedipine and verapamil partially inhibited Cch1–Mid1 activity, but typical P/Q-, N-, R- and T-type VGCC blockers did not inhibit activity. In contrast, a third L-type VGCC blocker, diltiazem, increased Cch1–Mid1 activity. Diltiazem did not increase Ca 2+ uptake in the cch1 and mid1 single mutants and the cch1 mid1 double mutant, indicating that the diltiazem-induced increase in Ca 2+ uptake is completely dependent on Cch1–Mid1. These results suggest that Cch1 is pharmacologically similar to L-type VGCCs, but the interactions between Cch1 and the L-type VGCC blockers are more complicated than expected. Abbreviations: BTZ, benzothiazepine; DHP, dihydropyridine; PAA, phenylalkylamine; TEA, tetraethylammonium; TTX, tetrodotoxin; VGCC, voltage-gated Ca 2+ channel These authors contributed equally to this work.