Sulfate uptake in photosynthetic Euglena gracilis. Mechanisms of regulation and contribution to cysteine homeostasis

► Plasma membrane sulfate uptake was coupled to H+ gradient in Euglena gracilis. ► Sulfate transporter activity increased under sulfate-deficiency or Cd2+ stress. ► Sulfate uptake was strongly inhibited by Cys accumulation. ► Sulfate uptake exerted control on the Cys concentration under sulfate deficiency.