Metabolic cycles provide building blocks and energy currency for the cell, but also signaling molecules that regulate diverse physiological responses from differentiation to aging. The metabolite S-adenosylmethionine (SAM) is one such factor that is used to regulate gene expression in the stress response, a key part of the aging process. We have discovered that individual SAM synthases has distinct effects and hypothesize that uncovering the mechanisms regulating local production of SAM will produce novel insights into stress-responses and aging.