Journal of Biological Chemistry
Volume 278, Issue 44, 31 October 2003, Pages 43051-43059
Journal home page for Journal of Biological Chemistry

Metabolism and Bioenergetics
Regulation of S-Adenosylmethionine Levels in Saccharomyces cerevisiae *

https://doi.org/10.1074/jbc.M308696200Get rights and content
Under a Creative Commons license
open access

Methylenetetrahydrofolate reductase (MTHFR) catalyzes the reduction of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate, used to methylate homocysteine in methionine biosynthesis. Methionine can be activated by ATP to give rise to the universal methyl donor, S-adenosylmethionine (AdoMet). Previously, a chimeric MTHFR (Chimera-1) comprised of the yeast Met13p N-terminal catalytic domain and the Arabidopsis thaliana MTHFR (AtMTHFR-1) C-terminal regulatory domain was constructed (Roje, S., Chan, S. Y., Kaplan, F., Raymond, R. K., Horne, D. W., Appling, D. R., and Hanson, A. D. (2002) J. Biol. Chem. 277, 4056–4061). Engineered yeast (SCY4) expressing Chimera-1 accumulated more than 100-fold more AdoMet and 7-fold more methionine than the wild type. Surprisingly, SCY4 showed no appreciable growth defect. The ability of yeast to hyperaccumulate AdoMet was investigated by studying the intracellular compartmentation of AdoMet as well as the mode of hyperaccumulation. Previous studies have established that AdoMet is distributed between the cytosol and the vacuole. A strain expressing Chimera-1 and lacking either vacuoles (vps33 mutant) or vacuolar polyphosphate (vtc1 mutant) was not viable when grown under conditions that favored AdoMet hyperaccumulation. The hyperaccumulation of AdoMet was a robust phenomenon when these cells were grown in medium containing glycine and formate but did not occur when these supplements were replaced by serine. The basis of the nutrient-dependent AdoMet hyperaccumulation effect is discussed in relation to homocysteine biosynthesis and sulfur metabolism.

Cited by (0)

*

This work was supported by National Institutes of Health Grant DK61428. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

Present address: Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Nine Cambridge Center, Cambridge, MA 02142-1479.