TY - JOUR
T1 - Redox responses in yeast to acetate as the carbon source
AU - Minard, Karyl I.
AU - McAlister-Henn, L.
N1 - Funding Information:
This work was supported by NIH RO1 AG017477 and NIH RO1 GM051265. We thank Sondra L. Anderson for assistance with chronological lifespan assays.
PY - 2009/3/1
Y1 - 2009/3/1
N2 - Following a shift to medium with acetate as the carbon source, a parental yeast strain exhibited a transient moderate 20% reduction in total cellular [NAD+ + NADH] but showed a ∼10-fold increase in the ratio of [NAD+]:[NADH] after 36 h. A mutant strain (idhΔ) lacking the tricarboxylic acid cycle enzyme isocitrate dehydrogenase had 50% higher cellular levels of [NAD+ + NADH] relative to the parental strain but exhibited similar changes in cofactor concentrations following a shift to acetate medium, despite an inability to grow on that carbon source; essentially all of the cofactor was in the oxidized form within 36 h. The salvage pathway for NAD(H) biosynthesis was found to be particularly important for viability during early transition of the parental strain to stationary phase in acetate medium. However, oxygen consumption was not affected, suggesting that the NAD(H) produced during this time may support other cellular functions. The idhΔ mutant exhibited increased flux through the salvage pathway in acetate medium but was dependent on the de novo pathway for viability. Long-term chronological lifespans of the parental and idhΔ strains were similar, but viability of the mutant strain was dependent on both pathways for NAD(H) biosynthesis.
AB - Following a shift to medium with acetate as the carbon source, a parental yeast strain exhibited a transient moderate 20% reduction in total cellular [NAD+ + NADH] but showed a ∼10-fold increase in the ratio of [NAD+]:[NADH] after 36 h. A mutant strain (idhΔ) lacking the tricarboxylic acid cycle enzyme isocitrate dehydrogenase had 50% higher cellular levels of [NAD+ + NADH] relative to the parental strain but exhibited similar changes in cofactor concentrations following a shift to acetate medium, despite an inability to grow on that carbon source; essentially all of the cofactor was in the oxidized form within 36 h. The salvage pathway for NAD(H) biosynthesis was found to be particularly important for viability during early transition of the parental strain to stationary phase in acetate medium. However, oxygen consumption was not affected, suggesting that the NAD(H) produced during this time may support other cellular functions. The idhΔ mutant exhibited increased flux through the salvage pathway in acetate medium but was dependent on the de novo pathway for viability. Long-term chronological lifespans of the parental and idhΔ strains were similar, but viability of the mutant strain was dependent on both pathways for NAD(H) biosynthesis.
KW - Chronological lifespan
KW - Isocitrate dehydrogenase
KW - NAD(H) levels
KW - Redox status in stationary phase
KW - Redox status in yeast cells
KW - Salvage and de novo pathways for NAD(H) synthesis
KW - Tricarboxylic acid cycle
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U2 - 10.1016/j.abb.2008.12.014
DO - 10.1016/j.abb.2008.12.014
M3 - Article
C2 - 19138656
AN - SCOPUS:59849108597
VL - 483
SP - 136
EP - 143
JO - Archives of Biochemistry and Biophysics
JF - Archives of Biochemistry and Biophysics
SN - 0003-9861
IS - 1
ER -