Molecular chaperone machines: chaperone activities of the cyclophilin Cyp-40 and the steroid aporeceptor-associated protein p23.
Molecular chaperones are essential proteins that participate in the regulation of steroid receptors in eukaryotes. The steroid aporeceptor complex contains the molecular chaperones Hsp90 and Hsp70, p48, the cyclophilin Cyp-40, and the associated proteins p23 and p60. In vitro folding assays showed that Cyp-40 and p23 functioned as molecular chaperones in a manner similar to that of Hsp90 or Hsp70. Although neither Cyp-40 nor p23 could completely refold an unfolded substrate, both proteins interacted with the substrate to maintain a nonnative folding-competent intermediate. Thus, the steroid aporeceptor complexes have multiple chaperone components that maintain substrates in an intermediate folded state.
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Department of Biochemistry, Molecular Biology and Cell Biology, Rice Institute for Biomedical Research, Northwestern University, 2153 North Campus Drive, Evanston, IL 60208, USA. r-morimoto@nwu.edu
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Morimoto
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D000591:Amino Acid Isomerases / Q000378:metabolism / Q000502:physiology*; D002352:Carrier Proteins / Q000378:metabolism / Q000502:physiology*; D000081406:Peptidyl-Prolyl Isomerase F; D021983:Cyclophilins; D050883:HSC70 Heat-Shock Proteins; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000378:metabolism; D006358:Hot Temperature; D018832:Molecular Chaperones / Q000378:metabolism / Q000502:physiology*; D019696:Peptidylprolyl Isomerase; D010750:Phosphoproteins / Q000378:metabolism / Q000502:physiology*; D000071876:Prostaglandin-E Synthases; D011487:Protein Conformation; D011489:Protein Denaturation; D017510:Protein Folding; D012995:Solubility; D001616:beta-Galactosidase / Q000737:chemistry
D002352:Carrier Proteins; D000081406:Peptidyl-Prolyl Isomerase F; D050883:HSC70 Heat-Shock Proteins; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; C000631446:PPIF protein, mouse; D010750:Phosphoproteins; C489791:Stip1 protein, mouse; D001616:beta-Galactosidase; D000591:Amino Acid Isomerases; D021983:Cyclophilins; D019696:Peptidylprolyl Isomerase; C490849:PTGES3 protein, human; D000071876:Prostaglandin-E Synthases