The KEF C15 is a potassium efflux system that is primarily found in Escherichia coli, functioning in the exchange of intracellular potassium (K+) for external protons (H+) in response to environmental stresses. It operates under the mechanism of glutathione (GSH)-gated K+ efflux, where the activity of the transporter is regulated by the presence of GSH and its adducts. The KEF transporter is part of the CPA2 superfamily, and it plays a critical role in maintaining cellular homeostasis by modulating intracellular potassium levels, particularly during oxidative stress. The KefC protein, a key component of this system, consists of multiple transmembrane helices and regulatory domains that facilitate its ion transport functions. Structural insights suggest that the transport mechanism involves conformational changes driven by ion binding and regulatory interactions.
