Activation and significance of vacuolar H+-ATPase in Saccharomyces cerevisiae adaptation and resistance to the herbicide 2,4-dichlorophenoxyacetic acid.
The stimulation of the activity of the H(+)-ATPase present in the vacuolar membrane (V-ATPase) of Saccharomyces cerevisiae is here described in response to a moderate stress induced by 2,4-dichlorophenoxyacetic acid (2,4-D). This in vivo activation (up to 5-fold) took place essentially during the adaptation period, preceding cell division under herbicide stress, in coordination with a marked activation of plasma membrane H(+)-ATPase (PM-ATPase) (up to 30-fold) and the decrease of intracellular and vacuolar pH values, suggesting that activation may be triggered by acidification. Single deletion of VMA1 and genes encoding other V-ATPase subunits led to a more extended period of adaptation and to slower growth under 2,4-D stress. Results suggest that a functional V-ATPase is required to counteract, more rapidly and efficiently, the dissipation of the physiological H(+)-gradient across vacuolar membrane registered during 2,4-D adaptation.
Fernandes
A R
AR
Biological Sciences Research Group, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, 1049-001, Lisbon, Portugal.
Durão
P J
PJ
Santos
P M
PM
Sá-Correia
I
I
D015084:2,4-Dichlorophenoxyacetic Acid / Q000494:pharmacology*; D000222:Adaptation, Physiological / Q000502:physiology*; D000595:Amino Acid Sequence; D002462:Cell Membrane / Q000737:chemistry / Q000187:drug effects / Q000201:enzymology; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004351:Drug Resistance / Q000502:physiology; D004361:Drug Tolerance / Q000502:physiology*; D004789:Enzyme Activation / Q000187:drug effects; D006540:Herbicides / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D009154:Mutation; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development*; D013329:Structure-Activity Relationship; D025262:Vacuolar Proton-Translocating ATPases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
D006540:Herbicides; D015084:2,4-Dichlorophenoxyacetic Acid; D025262:Vacuolar Proton-Translocating ATPases