Acetyl-CoA-dependent processes are preferentially supported by local metabolite synthesis.

The cell nucleus is an active metabolic site. Numerous enzymes best known for their roles in cytosolic or mitochondrial pathways also function in the nucleus, where they contribute to gene regulation and DNA replication and repair. Although metabolites can diffuse through nuclear pores, it remains unclear the extent to which the nucleus and cytosol operate as continuous versus distinct metabolic spaces. Both compartments require acetyl-CoA-for example, for histone acetylation and lipid synthesis-and the acetyl-CoA generating enzyme ATP-citrate lyase (ACLY) resides in both locations, but the significance of its dual localization is incompletely understood. Using cell lines in which ACLY is localized to either compartment, we find that ACLY in either location supports fatty acid synthesis and histone acetylation, yet compartment-localized ACLY enables finer control. Nuclear ACLY preserves histone H3K23 acetylation under glucose limitation and modulates specific transcriptional programs, whereas cytosolic ACLY most efficiently supports lipid biosynthetic fluxes. Thus, local synthesis defines a preferential metabolic fate, providing more precise regulation.