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Phospholipase C is required for glucose‐induced calcium influx in budding yeast
Author(s) -
Tisi Renata,
Baldassa Simona,
Belotti Fiorella,
Martegani Enzo
Publication year - 2002
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(02)02806-5
Subject(s) - aequorin , calcium , photoprotein , phospholipase c , calcium in biology , second messenger system , intracellular , snf3 , biochemistry , biology , saccharomyces cerevisiae , glucose transporter , microbiology and biotechnology , chemistry , yeast , receptor , insulin , endocrinology , bioluminescence , organic chemistry
Intracellular calcium is a second messenger involved in several processes in yeast, such as mating, nutrient sensing, stress response and cell cycle events. It was reported that glucose addition stimulates a rapid increase in free calcium level in yeast. To investigate the calcium level variations induced by different stimuli we used a reporter system based on the photoprotein aequorin. Glucose addition (50 mM) to nutrient‐starved cells induced an increase in free intracellular calcium concentration, mainly due to an influx from external medium. The increase of calcium reached its maximum 100–120 s after the stimulus. A concentration of about 20 mM glucose was required for a 50% increase in intracellular calcium. This response was completely abolished in strain plc1 Δ and in the isogenic wild‐type strain treated with 3‐nitrocoumarin, a phosphatidylinositol‐specific phospholipase C inhibitor, suggesting that Plc1p is essential for glucose‐induced calcium increase. This suggests that Plc1p should have a significant role in transducing glucose signal. The calcium influx induced by addition of high glucose on cells previously stimulated with low glucose levels was inhibited in strains with a deletion in the GPR1 or GPA2 genes, which suggests that glucose would be detected through the Gpr1p/Gpa2p receptor/G protein‐coupled (GPCR) complex. Moreover, the signal was completely abolished in a strain unable to phosphorylate glucose, which is consistent with the reported requirement of glucose phosphorylation for GPCR complex activation.