title: Taurine chloramine-induced inactivation of cofilin protein through methionine oxidation.
abstract: Cofilin regulates reorganization of actin filaments (F-actin) in eukaryotes. A recent finding has demonstrated that oxidation of cofilin by taurine chloramine (TnCl), a physiological oxidant derived from neutrophils, causes cofilin to translocate to the mitochondria inducing apoptosis (F. Klamt et al. Nat. Cell Biol.11:1241-1246; 2009). Here we investigated the effect of TnCl on biological activities of cofilin in vitro. Our data show that TnCl-induced oxidation of recombinant human cofilin-1 inhibits its F-actin-binding and depolymerization activities. Native cofilin contains four free Cys and three Met residues. Incubation of oxidized cofilin with DTT does not lead to its reactivation. A double Cys to Ala mutation on the two C-terminal Cys shows similar biological activities as the wild type, but does not prevent the TnCl-induced inactivation. In contrast, incubation of oxidized cofilin with methionine sulfoxide reductases results in its reactivation. Phosphorylation is known to inhibit cofilin activities. We found that Met oxidation also prevents phosphorylation of cofilin, which is reversed by incubating oxidized cofilin with methionine sulfoxide reductases. Interestingly, intact protein mass spectrometry of the oxidized mutant indicated one major oxidation product with an additional mass of 16 Da, consistent with oxidation of one specific Met residue. This residue was identified as Met-115 by peptide mapping and tandem mass spectrometry. It is adjacent to Lys-114, a known residue on globular-actin-binding site, implying that oxidation of Met-115 disrupts the globular-actin-binding site of cofilin, which causes TnCl-induced inactivation. The findings identify Met-115 as a redox switch on cofilin that regulates its biological activity.
authors: Division of Therapeutic Proteins, Office of Biotechnology Products, Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA. Electronic address: shen.luo@fda.hhs.gov.
authors: Shen
authors: S
authors: Luo
authors: Division of Therapeutic Proteins, Office of Biotechnology Products, Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA. Electronic address: hiroshi.uehara@fda.hhs.gov.
authors: Hiroshi
authors: H
authors: Uehara
authors: Division of Therapeutic Proteins, Office of Biotechnology Products, Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, MD 20993, USA. Electronic address: emily.shacter@thinkfda.com.
authors: Emily
authors: E
authors: Shacter
mesh_terms: D051339:Actin Depolymerizing Factors / Q000737:chemistry* / Q000235:genetics; D000199:Actins / Q000378:metabolism*; D019943:Amino Acid Substitution; D001665:Binding Sites; D004229:Dithiothreitol / Q000737:chemistry; D006801:Humans; D008715:Methionine / Q000378:metabolism*; D051150:Methionine Sulfoxide Reductases / Q000378:metabolism; D008958:Models, Molecular; D010084:Oxidation-Reduction; D010766:Phosphorylation; D011485:Protein Binding; D013654:Taurine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology
chemical_list: D051339:Actin Depolymerizing Factors; D000199:Actins; D013654:Taurine; C043410:N-chlorotaurine; D008715:Methionine; D051150:Methionine Sulfoxide Reductases; D004229:Dithiothreitol
keywords: Actin; Cofilin; G-actin-binding site; Mass spectrometry; Methionine oxidation; Methionine sulfoxide reductases; Oxidative stress; Phosphorylation; Taurine chloramine