Amiodarone induces a caffeine‐inhibited, MID1‐depedent rise in free cytoplasmic calcium in Saccharomyces cerevisiae

Abstract

SummaryCalcium signalling is involved in myriad cellular processes such as mating morphogenesis. Mating in yeast induces changes in cell morphology with a concomitant increase in calcium uptake that is dependent on the MID1 and CCH1 genes. Mid1p and Cch1p are believed to function in a capacitive calcium entry (CCE)-like process. Amiodarone alters mammalian calcium channel activity but, despite its clinical importance, its molecular mechanisms are not clearly defined. We have shown previously that amiodarone has fungicidal activity against a broad array of fungi. We show here that amiodarone causes a dramatic increase in cytoplasmic calcium ([Ca 2+ + + + ] cyt ) in Saccharomyces cerevisiae . The majority of this increase is dependent on extracellular Ca 2+ + + + nonetheless, a significant increase in [Ca 2+ + + + ] cyt is still induced by amiodarone when no uptake of extracellular Ca 2+ + + + can occur. The influx of extracellular Ca 2+ + + + may be a direct effect of amiodarone on a membrane transporter or may be by a CCE mechanism. Uptake of the extracellular Ca 2+ + + + is inhibited by caffeine and reduced in strains deleted for the mid1 gene, but not in cells deleted for cch1 . Our data are the first demonstrating control of yeast calcium channels by amiodarone and caffeine.

Cch1 and Mid1 Are Functionally Required for Vegetative Growth under Low-Calcium Conditions in the Phytopathogenic Ascomycete Botrytis cinerea

“…The functionality of the calcium detection system has been demonstrated, and future studies will focus on the different behaviors of mutants defective in different calcium cascade components under various stress conditions, such as Ca 2ϩ , pH, and oxidative stresses, or stresses induced by using calcium channel blockers (nifedipine, diltiazem), or the calcium ionophore A23187. However, we were unable to present data confirming the hypothesis of separate functions of Mid1 and Cch1 by AMD treatment, as shown by Courchesne and Ozturk for S. cerevisiae (50). Another study showed enhanced growth sensitivity of ⌬mid1 and ⌬cch1 mutants to AMD over that of the wild type, also revealing discrepancies between the effects of this drug on Mid1 and Cch1 protein functions (59).…”

“…However, these proteins can still respond to some stimuli differently, suggesting common but also individual functions of the two channels (24,50). Recently, it has been shown by a yeast two-hybrid approach that these proteins also interact in A. nidulans (55).…”

“…The light output was recorded in relative luminescence units (RLU). Amiodarone (AMD) (amiodarone hydrochloride; Sigma-Aldrich Chemie, Steinheim, Germany) was dissolved in 12% ethanol (EtOH) according to the method of Courchesne and Ozturk (50). GB5 medium containing 12% EtOH was used as a control for AMD treatment.…”

“…8). In yeast, it has been shown that amiodarone (AMD) affects calcium homeostasis and causes a dramatic increase in the cytoplasmic calcium concentration, leading to cell death after short exposures (50). The rise in [Ca 2ϩ ] cyt after AMD treatment appeared to result from both release of Ca 2ϩ from intracellular stores and stimulation of caffeine-sensitive calcium entry.…”

Derivatives of benzo[b]furan. Part II. Structural studies of derivatives of 2- and 3-benzo[b]furancarboxylic acids

“…Recently, it was proved that derivatives of the 2-and 3-benzo [b]furancarboxylic acids showed also selective cytotoxicity against the human cancer cell lines [8,9]. Moreover, the compounds containing the benzo [b]furan system show antiprotozoal and/or antifungal activity [10][11][12][13], e.g., amiodarone, a drug used as an antiarrhythmic agent, possess significant antifungal potential [14][15][16][17][18][19]. The derivatives of 2-and 3-benzo [b]furan-carboxylic acids, especially those containing halogen atom (Br or Cl) in their structure, are active against the Candida strains C. albicans and C. parapsilosis [20,21], Mycobacterium tuberculosis [22] and are selective Pim kinase inhibitors [23].…”