title: Redox-regulated molecular chaperones.
abstract: The conserved heat shock protein Hsp33 functions as a potent molecular chaperone with a highly sophisticated regulation. On transcriptional level, the Hsp33 gene is under heat shock control; on posttranslational level, the Hsp33 protein is under oxidative stress control. This dual regulation appears to reflect the close but rather neglected connection between heat shock and oxidative stress. The redox sensor in Hsp33 is a cysteine center that coordinates zinc under reducing, inactivating conditions and that forms two intramolecular disulfide bonds under oxidizing, activating conditions. Hsp33's redox-regulated chaperone activity appears to specifically protect proteins and cells from the otherwise deleterious effects of reactive oxygen species. That redox regulation of chaperone activity is not restricted to Hsp33 became evident when the chaperone activity of protein disulfide isomerase was recently also shown to cycle between a low- and high-affinity substrate binding state, depending on the redox state of its cysteines.
authors.affiliation: Department of Molecular, Cellular and Developmental Biology, University of Michigan, 830 N. University Avenue, Ann Arbor, Michigan 48109-1048, USA.
authors.forename: P C F
authors.initials: PC
authors.lastname: Graf
authors.forename: U
authors.initials: U
authors.lastname: Jakob
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D001665:Binding Sites; D019281:Dimerization; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000737:chemistry* / Q000378:metabolism*; D010084:Oxidation-Reduction; D011487:Protein Conformation
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; C492165:HSP33 protein, E coli; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones