Ca(2+) and H+ homeostasis in fission yeast: a role of Ca(2+)/H+ exchange and distinct V-H+-ATPases of the secretory pathway organelles.
We determined the H+ and Ca(2+) uptake by fission yeast membranes separated on sucrose gradient and found that (i) Ca(2+) sequestering is due to Ca(2+)/H+ antiporter(s) localized to secretory pathway organelles while Ca(2+)-ATPase activity is not detectable in their membranes; (ii) immunochemically distinct V-H+-ATPases acidify the lumen of the secretory pathway organelles. The data indicate that the endoplasmic reticulum, Golgi and vacuole form a network of Ca(2+) and H+ stores in the single cell, providing favorable conditions for such key processes as protein folding/sorting, membrane fusion, ion homeostasis and Ca(2+) signaling in a differential and local manner.
Okorokov
L A
LA
Laboratório de Fisiologia e Bioquímica de Microrganismos, Centro de Biociências e Biotecnologia, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes-RJ, CEP 28015-620, Brazil. okorokov@uenf.br
Silva
F E
FE
Okorokova Façanha
A L
AL
D000255:Adenosine Triphosphate / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000935:Antifungal Agents / Q000494:pharmacology; D017920:Antiporters / Q000378:metabolism / Q000502:physiology*; D002118:Calcium / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D027682:Cation Transport Proteins; D002462:Cell Membrane / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004721:Endoplasmic Reticulum / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism; D006859:Hydrogen / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D015151:Immunoblotting; D007476:Ionophores / Q000494:pharmacology; D018942:Macrolides; D017510:Protein Folding; D006180:Proton-Translocating ATPases / Q000502:physiology*; D012568:Schizosaccharomyces / Q000378:metabolism*; D015398:Signal Transduction; D013395:Sucrose / Q000378:metabolism; D025262:Vacuolar Proton-Translocating ATPases; D014617:Vacuoles / Q000378:metabolism
D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D017920:Antiporters; D002135:Calcium-Binding Proteins; D027682:Cation Transport Proteins; D007476:Ionophores; D018942:Macrolides; C027614:calcium-hydrogen antiporters; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; D013395:Sucrose; D006859:Hydrogen; C040929:bafilomycin A1; D000255:Adenosine Triphosphate; D025262:Vacuolar Proton-Translocating ATPases; D006180:Proton-Translocating ATPases; D002118:Calcium