title: The outer mitochondrial membrane protein mitoNEET contains a novel redox-active 2Fe-2S cluster.
abstract: The outer mitochondrial membrane protein mitoNEET was discovered as a binding target of pioglitazone, an insulin-sensitizing drug of the thiazolidinedione class used to treat type 2 diabetes (Colca, J. R., McDonald, W. G., Waldon, D. J., Leone, J. W., Lull, J. M., Bannow, C. A., Lund, E. T., and Mathews, W. R. (2004) Am. J. Physiol. 286, E252-E260). We have shown that mitoNEET is a member of a small family of proteins containing a 39-amino-acid CDGSH domain. Although the CDGSH domain is annotated as a zinc finger motif, mitoNEET was shown to contain iron (Wiley, S. E., Murphy, A. N., Ross, S. A., van der Geer, P., and Dixon, J. E. (2007) Proc. Natl. Acad. Sci. U. S. A. 104, 5318-5323). Optical and electron paramagnetic resonance spectroscopy showed that it contained a redox-active pH-labile Fe-S cluster. Mass spectrometry showed the loss of 2Fe and 2S upon cofactor extrusion. Spectroscopic studies of recombinant proteins showed that the 2Fe-2S cluster was coordinated by Cys-3 and His-1. The His ligand was shown to be involved in the observed pH lability of the cluster, indicating that loss of this ligand via protonation triggered release of the cluster. mitoNEET is the first identified 2Fe-2S-containing protein located in the outer mitochondrial membrane. Based on the biophysical data and domain fusion analysis, mitoNEET may function in Fe-S cluster shuttling and/or in redox reactions.
authors.affiliation: Department of Pharmacology, University of California, San Diego, La Jolla, California 92093, USA.
authors.forename: Sandra E
authors.initials: SE
authors.lastname: Wiley
authors.forename: Mark L
authors.initials: ML
authors.lastname: Paddock
authors.forename: Edward C
authors.initials: EC
authors.lastname: Abresch
authors.forename: Larry
authors.initials: L
authors.lastname: Gross
authors.forename: Peter
authors.initials: P
authors.lastname: van der Geer
authors.forename: Rachel
authors.initials: R
authors.lastname: Nechushtai
authors.forename: Anne N
authors.initials: AN
authors.lastname: Murphy
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Jennings
authors.forename: Jack E
authors.initials: JE
authors.lastname: Dixon
mesh_terms: D001665:Binding Sites; D003545:Cysteine; D006639:Histidine; D006801:Humans; D006863:Hydrogen-Ion Concentration; D033862:Iron-Binding Proteins / Q000737:chemistry*; D007506:Iron-Sulfur Proteins / Q000737:chemistry*; D008565:Membrane Proteins / Q000737:chemistry*; D051336:Mitochondrial Membranes / Q000737:chemistry; D024101:Mitochondrial Proteins / Q000737:chemistry*; D010084:Oxidation-Reduction; D013057:Spectrum Analysis; D016335:Zinc Fingers
chemical_list: C525595:CISD1 protein, human; D033862:Iron-Binding Proteins; D007506:Iron-Sulfur Proteins; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D006639:Histidine; D003545:Cysteine