sepharose has been researched along with geldanamycin* in 2 studies
2 other study(ies) available for sepharose and geldanamycin
| Article | Year |
|---|---|
Polymorphic glutathione S-transferase subunit 3 of rat liver exhibits different susceptibilities to carbon tetrachloride: differences in their interactions with heat-shock protein 90.
Rat glutathione S-transferase (GST) subunit 3 gene has polymorphism, one type encoding Asn(198)-Cys(199) (NC type) and another encoding Lys(198)-Ser(199) (KS type). To examine whether the two types of GST 3-3 exhibit different susceptibilities to oxidative stress in vivo, rats were administered with CCl(4), a hepatotoxin causing severe oxidative stress, and its effect on liver GST 3-3 was compared. Decrease in GST activities in liver due to CCl(4) administration was more evident in NC type rats than in KS type rats, and most GST activities of KS type rats were confined to S-hexylglutathione-Sepharose, whereas those of NC type rats were not. Decreases in GST subunits 1 and 3 were more marked in NC type rats and glutathiolated NC type GST 3-3 was also detected. These results indicated that KS and NC type GST 3-3 of rat livers exhibited different susceptibilities to CCl(4) in vivo. A protein consisting of a subunit with molecular mass of 90 kDa was shown to bind to KS type GST 3-3 but not to NC type. This protein was identified as heat-shock protein (HSP) 90beta by N-terminal amino acid sequencing and immunoblotting. A specific HSP90 inhibitor geldanamycin released their binding. There was no difference in the binding of apoptosis signal-regulating kinase 1 to GST 3-3 between NC and KS type rats. These findings suggest that HSP90 interacts with KS type GST 3-3 and thereby protects it from inactivation due to CCl(4). Topics: Animals; Benzoquinones; Carbon Tetrachloride; Chromatography, Affinity; Chromatography, High Pressure Liquid; Dithiothreitol; Enzyme Inhibitors; Glutathione; Glutathione Transferase; HSP90 Heat-Shock Proteins; Immunoblotting; Isoenzymes; Lactams, Macrocyclic; Liver; MAP Kinase Kinase Kinase 5; MAP Kinase Kinase Kinases; Oxidative Stress; Polymorphism, Genetic; Protein Binding; Protein-Tyrosine Kinases; Quinones; Rats; Rats, Sprague-Dawley; Sepharose | 2003 |
A Nucleotide-dependent molecular switch controls ATP binding at the C-terminal domain of Hsp90. N-terminal nucleotide binding unmasks a C-terminal binding pocket.
In vivo function of the molecular chaperone Hsp90 is ATP-dependent and requires the full-length protein. Our earlier studies predicted a second C-terminal ATP-binding site in Hsp90. By applying direct biochemical approaches, we mapped two ATP-binding sites and unveiled the C-terminal ATP-binding site as the first example of a cryptic chaperone nucleotide-binding site, which is opened by occupancy of the N-terminal site. We identified an N-terminal gamma-phosphate-binding motif in the middle domain of Hsp90 similar to other GHKL family members. This motif is adjacent to the phosphate-binding region of the C-terminal ATP-binding site. Whereas novobiocin disrupts both C- and N-terminal nucleotide binding, we found a selective C-terminal nucleotide competitor, cisplatin, that strengthens the Hsp90-Hsp70 complex leaving the Hsp90-p23 complex intact. Cisplatin may provide a pharmacological tool to dissect C- and N-terminal nucleotide binding of Hsp90. A model is proposed on the interactions of the two nucleotide-binding domains and the charged region of Hsp90. Topics: Adenosine Triphosphate; Amino Acid Motifs; Amino Acid Sequence; Animals; Benzoquinones; Binding Sites; Circular Dichroism; Cisplatin; Cross-Linking Reagents; Dose-Response Relationship, Drug; Electrophoresis, Polyacrylamide Gel; HSP70 Heat-Shock Proteins; HSP90 Heat-Shock Proteins; Humans; Jurkat Cells; Kinetics; Lactams, Macrocyclic; Models, Biological; Molecular Sequence Data; Mutation; Precipitin Tests; Protein Binding; Protein Structure, Secondary; Protein Structure, Tertiary; Quinones; Rats; Sepharose; Sequence Homology, Amino Acid | 2002 |