Modulation of Potassium Channel Function by Methionine Oxidation and Reduction

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 94; no. 18; pp. 9932 - 9937
• Main Authors: Ciorba, Matthew A., Heinemann, Stefan H., Weissbach, Herbert, Brot, Nathan, Hoshi, Toshinori
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences of the United States of America 02.09.1997; National Acad Sciences; National Academy of Sciences; The National Academy of Sciences of the USA
• Subjects: Amino Acid Sequence; Amino acids; Animals; Biological Sciences; DNA; Enzymes; Ion Channel Gating; Methionine - metabolism; Molecular Sequence Data; Neurology; Neurons; Oocytes; Oocytes - metabolism; Oxidation; Oxidation-Reduction; Patch-Clamp Techniques; Potassium; Potassium channels; Potassium Channels - chemistry; Potassium Channels - metabolism; RNA; Sulfoxides; Time constants; Xenopus
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.94.18.9932

Oxidation of amino acid residues in proteins can be caused by a variety of oxidizing agents normally produced by cells. The oxidation of methionine in proteins to methionine sulfoxide is implicated in aging as well as in pathological conditions, and it is a reversible reaction mediated by a ubiquitous enzyme, peptide methionine sulfoxide reductase. The reversibility of methionine oxidation suggests that it could act as a cellular regulatory mechanism although no such in vivo activity has been demonstrated. We show here that oxidation of a methionine residue in a voltage-dependent potassium channel modulates its inactivation. When this methionine residue is oxidized to methionine sulfoxide, the inactivation is disrupted, and it is reversed by coexpression with peptide methionine sulfoxide reductase. The results suggest that oxidation and reduction of methionine could play a dynamic role in the cellular signal transduction process in a variety of systems.