Characterization of the human monothiol glutaredoxin 3 (PICOT) as iron-sulfur protein.
Mammalian glutaredoxin 3 (Grx3/PICOT) is an essential protein involved in the regulation of signal transduction, for instance during immune cell activation and development of cardiac hypertrophy, presumably in response to redox signals. This function requires the sensing of such stresses by a hitherto unknown mechanism. Here, we characterized Grx3/PICOT as iron-sulfur protein. The protein binds two bridging [2Fe-2S] clusters in a homodimeric complex with the active site cysteinyl residues of its two monothiol glutaredoxin domains and glutathione bound non-covalently to the Grx domains. Co-immunoprecipitation of 55-iron with Grx3/PICOT from Jurkat cells suggested the presence of these cofactors under physiological conditions. The [2Fe-2S]2+ clusters were not redox active, instead they were lost upon treatment of the holo protein with ferricyanide or S-nitroso glutathione. This redox-induced dissociation of the Grx3/PICOT holo complex may be a mechanism of Grx3/PICOT activation in response to reactive oxygen and nitrogen species.
Institut für Klinische Zytobiologie und Zytopathologie, Fachbereich Medizin, Philipps Universität Marburg, Germany.
Petra
P
Haunhorst
Carsten
C
Berndt
Susanne
S
Eitner
José R
JR
Godoy
Christopher Horst
CH
Lillig
D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D005292:Ferricyanides / Q000378:metabolism; D006801:Humans; D047468:Immunoprecipitation; D007501:Iron / Q000378:metabolism*; D007504:Iron Radioisotopes / Q000378:metabolism; D007506:Iron-Sulfur Proteins / Q000737:chemistry / Q000378:metabolism*; D019169:Jurkat Cells; D010084:Oxidation-Reduction; D011487:Protein Conformation; D055550:Protein Stability; D017434:Protein Structure, Tertiary; D026422:S-Nitrosoglutathione / Q000378:metabolism
D002352:Carrier Proteins; D005292:Ferricyanides; C404105:GLRX3 protein, human; D007504:Iron Radioisotopes; D007506:Iron-Sulfur Proteins; C007931:hexacyanoferrate III; D026422:S-Nitrosoglutathione; D007501:Iron