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In vitro and in vivo characterization of modulation of the vacuolar cation channel TRPY 1 from Saccharomyces cerevisiae
Author(s) -
Hamamoto Shin,
Mori Yasuo,
Yabe Isamu,
Uozumi Nobuyuki
Publication year - 2018
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/febs.14399
Subject(s) - phosphatidylinositol , cytosol , transient receptor potential channel , saccharomyces cerevisiae , microbiology and biotechnology , phosphatidylinositol 4,5 bisphosphate , trpc1 , biochemistry , vacuole , biophysics , chemistry , biology , signal transduction , yeast , receptor , cytoplasm , enzyme
Saccharomyces cerevisiae possesses a transient receptor potential ( TRP ) channel homolog TRPY 1 in its vacuolar membrane, considered to be an ancestral TRP channel. So far, studies have focused on the channel properties of TRPY 1, but its regulation and physiologic role remained to be elucidated. Here, we investigated TRPY 1 channel function in vitro and in vivo . Patch‐clamp recording of TRPY 1 in yeast vacuolar membranes showed that Ca 2+ on the lumen side inhibited TRPY 1‐mediated channel activity, whereas luminal Zn 2+ increased the currents. TRPY 1 was activated in the presence of a reducing agent, 2‐mercaptoethanol. The cysteine at position 624 was identified as the target for this activating action. This activation was independent of the presence of cytosolic Ca 2+ . The amplitude of TRPY 1‐mediated current was reduced by addition of phosphatidylinositol 3‐phosphate on the cytosolic side but not by phosphatidylinositol (PI) or phosphatidylinositol 3,5‐phosphate. Measurement of the transient Ca 2+ increase in response to hyper‐osmotic shock in several yeast mutants defective in different steps of the PI phosphate biogenesis pathway supported this interpretation. Addition of a microtubule inhibitor strongly decreased the transient cytosolic Ca 2+ increase upon hyper‐osmotic shock. Taken together, the data indicate that the vacuolar TRPY 1 Ca 2+ channel mediates the perception of cytosolic signals that were induced by external changes in osmolarity, and participates in the modulation of cytosolic calcium signaling through Ca 2+ release from the vacuole to maintain intracellular Ca 2+ homeostasis in yeast.