The vacuolar Ca2+/H+ exchanger Vcx1p/Hum1p tightly controls cytosolic Ca2+ levels in S. cerevisiae.
It is well established that the vacuole plays an important role in the cellular adaptation to growth in the presence of elevated extracellular Ca2+ concentrations in Saccharomyces cerevisiae. The Ca2+ ATPase Pmc1p and the Ca2+/H+ exchanger Vcx1p/Hum1p have been shown to facilitate Ca2+ sequestration into the vacuole. However, the distinct physiological roles of these two vacuolar Ca2+ transporters remain uncertain. Here we show that Vcx1p can rapidly sequester a sudden pulse of cytosolic Ca2+ into the vacuole, while Pmc1p carries out this function much less efficiently. This finding is consistent with the postulated role of Vcx1p as a high capacity, low affinity Ca2+ transporter and suggests that Vcx1p may act to attenuate the propagation of Ca2+ signals in this organism.
Miseta
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A
Department of Microbiology, The University of Alabama at Birmingham, 35294, USA.
Kellermayer
R
R
Aiello
D P
DP
Fu
L
L
Bedwell
D M
DM
D000331:Aequorin / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D017920:Antiporters / Q000502:physiology*; D002118:Calcium / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000502:physiology*; D000252:Calcium-Transporting ATPases / Q000502:physiology; D027682:Cation Transport Proteins; D003600:Cytosol / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005656:Fungal Proteins / Q000502:physiology; D007474:Ion Exchange; D018942:Macrolides; D016296:Mutagenesis; D053499:Plasma Membrane Calcium-Transporting ATPases; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D013997:Time Factors; D014617:Vacuoles / Q000378:metabolism*
D000900:Anti-Bacterial Agents; D017920:Antiporters; D002135:Calcium-Binding Proteins; D027682:Cation Transport Proteins; D004791:Enzyme Inhibitors; D005656:Fungal Proteins; D018942:Macrolides; C085484:PMC1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C099946:VCX1 protein, S cerevisiae; C027614:calcium-hydrogen antiporters; D000331:Aequorin; C040929:bafilomycin A1; D053499:Plasma Membrane Calcium-Transporting ATPases; D000252:Calcium-Transporting ATPases; D002118:Calcium