Organellar mechanosensitive channels in fission yeast regulate the hypo-osmotic shock response.
A key molecule of sensing machineries essential for survival upon hypo-osmotic shock is the mechanosensitive channel. The bacterial mechanosensitive channel MscS functions directly for this purpose by releasing cytoplasmic solutes out of the cell, whereas plant MscS homologues are found to function in chloroplast organization. Here we show that the fission yeast MscS homologues, designated Msy1 and Msy2, participate in the hypo-osmotic shock response by a mechanism different from that operated by the bacterial MscS. Upon hypo-osmotic shock, msy2(-) and msy1(-)                 msy2(-) cells display greater cell swelling than wild-type cells and undergo cell death. Cell swelling precedes an intracellular Ca(2+) increase, which was greater in msy1(-) and msy1(-)                 msy2(-) cells than in wild-type cells. Fluorescent microscopy showed that Msy1 and Msy2 localize mainly to the endoplasmic reticulum. These observations suggest that organellar Msy1 and Msy2 regulate intracellular Ca(2+) and cell volume for survival upon hypo-osmotic shock.
Department of Biology, Tokyo Gakugei University, 4-1-1 Nukui Kita-machi, Koganei-shi, Tokyo 184-8501, Japan. y_nakayama9339@nifty.com
Yoshitaka
Y
Nakayama
Kenjiro
K
Yoshimura
Hidetoshi
H
Iida
D000595:Amino Acid Sequence; D002118:Calcium / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000235:genetics / Q000378:metabolism*; D005658:Fungi / Q000145:classification / Q000235:genetics / Q000378:metabolism; D040542:Mechanotransduction, Cellular; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009997:Osmotic Pressure; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D012568:Schizosaccharomyces / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment
D004268:DNA-Binding Proteins; D008565:Membrane Proteins; C486643:Msc1 protein, S pombe; C577897:Msy1 protein, S pombe; C577898:Msy2 protein, S pombe; D029702:Schizosaccharomyces pombe Proteins; D002118:Calcium