Evidence for nuclear control of amino acid transport in cultured cells

Abstract

CELLS incubated in an amino acid-free Krebs–Ringer buffer, or grown in medium with a reduced amino acid concentration, respond by increasing their ability to actively transport amino acids^1–3. Studies using inhibitors of mRNA transcription and translocation suggested that this regulatory control involves mRNA transcription and the synthesis of protein intimately concerned with the transport process. We determined nuclear involvement using cells enucleated by prior treatment with the fungal metabolite cytochalasin B (ref. 4). The results presented here suggest that the nuclei of HeLa cells are important for maintaining and modifying their amino acid transport capacity in response to a reduction in the external amino acid concentration.