Vba4p, a vacuolar membrane protein, is involved in the drug resistance and vacuolar morphology of Saccharomyces cerevisiae

• Published in: Bioscience, biotechnology, and biochemistry biotechnology, and biochemistry, 2016-02, Vol.80 (2), p.279-287
• Main Authors: Kawano-Kawada, Miyuki, Pongcharoen, Pongsanat, Kawahara, Rieko, Yasuda, Mayu, Yamasaki, Takashi, Akiyama, Koichi, Sekito, Takayuki, Kakinuma, Yoshimi
• Format: Article
• Language: English
• Subjects: Amino Acid Transport Systems, Basic - genetics; Amino Acid Transport Systems, Basic - metabolism; Amino Acids - metabolism; Antifungal Agents - pharmacology; azole; Biological Transport; Drug Resistance, Fungal - genetics; Fluconazole - pharmacology; Gene Expression; Intracellular Membranes - drug effects; Intracellular Membranes - metabolism; Intracellular Membranes - ultrastructure; Ketoconazole - pharmacology; Miconazole - pharmacology; multidrug resistance; Organelle Shape; Protein Isoforms - genetics; Protein Isoforms - metabolism; Protein Structure, Secondary; Protein Structure, Tertiary; Saccharomyces cerevisiae - drug effects; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae - ultrastructure; Salt-Tolerance; Sodium Chloride - pharmacology; vacuolar transporter; Vacuoles - drug effects; Vacuoles - metabolism; Vacuoles - ultrastructure
• ISSN: 0916-8451; 1347-6947
• DOI: 10.1080/09168451.2015.1083401

In the vacuolar basic amino acid (VBA) transporter family of Saccharomyces cerevisiae, VBA4 encodes a vacuolar membrane protein with 14 putative transmembrane helices. Transport experiments with isolated vacuolar membrane vesicles and estimation of the amino acid contents in vacuoles showed that Vba4p is not likely involved in the transport of amino acids. We found that the vba4Δ cells, as well as vba1Δ and vba2Δ cells, showed increased susceptibility to several drugs, particularly to azoles. Although disruption of the VBA4 gene did not affect the salt tolerance of the cells, vacuolar fragmentation observed under high salt conditions was less prominent in vba4Δ cells than in wild type, vba1Δ, and vba2Δ cells. Vba4p differs from Vba1p and Vba2p as a vacuolar transporter but is important for the drug resistance and vacuolar morphology of S. cerevisiae. Vba4p is a vacuolar membrane protein in the VBA transporter family of Saccharomyces cerevisiae (A). Disruption of VBA4 resulted in increased susceptibility to azoles (B).