Purification, subunit structure, and DNA binding properties of the mouse oxysterol receptor.
A cytosolic receptor protein for oxygenated sterols, postulated to be involved in the regulation of 3-hydroxy-3-methylglutaryl-CoA reductase and cholesterol biosynthesis, has been purified from mouse L cell cytosol greater than 3,600-fold in its undenatured form and to apparent homogeneity upon further electrophoresis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The purified 7.5 S receptor appears to be a dimer with similar or identical subunits of Mr 95,000. Proteolytic cleavage by an endogenous factor(s) gives rise to a 4.2 S form of the receptor which is resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis into a heterogeneous mixture of ligand binding fragments of Mr 30,000-60,000. This 4.2 S form of the receptor retains high affinity for the oxysterol ligand and exhibits a more rapid oxysterol binding rate than the 7.5 S form. The 7.5 S form of the receptor binds to DNA-cellulose at low salt concentrations at neutral pH, and its affinity increases at low pH or in the presence of Zn2+. Receptor preparations from mouse liver were purified approximately 900-fold by the same purification procedure, but this was accompanied by conversion of the 7.5 S liver receptor to a approximately 4 S form, Mr approximately 55,000.
Taylor
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FR
Jackson Laboratory, Bar Harbor, Maine 04609.
Shown
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EP
Thompson
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EB
Kandutsch
A A
AA
D000345:Affinity Labels; D000818:Animals; D002499:Centrifugation, Density Gradient; D002845:Chromatography; D004247:DNA / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D007739:L Cells; D008099:Liver / Q000032:analysis; D046911:Macromolecular Substances; D051379:Mice; D008970:Molecular Weight; D010447:Peptide Hydrolases / Q000378:metabolism; D010777:Photochemistry; D011480:Protease Inhibitors / Q000494:pharmacology; D011987:Receptors, Steroid / Q000302:isolation & purification* / Q000378:metabolism; D015032:Zinc / Q000494:pharmacology; D000098825:Oxysterol Binding Proteins
D000345:Affinity Labels; D046911:Macromolecular Substances; D011480:Protease Inhibitors; D011987:Receptors, Steroid; D000098825:Oxysterol Binding Proteins; D004247:DNA; D010447:Peptide Hydrolases; D015032:Zinc