The regulation of intracellular transport of cholesterol in bovine adrenal cells: purification of a novel protein.
We have purified to homogeneity a protein from bovine adrenal (fasciculata) cells that is capable of: 1) stimulating synthesis of pregnenolone (in a concentration-dependent fashion) by mitochondria when added with exogenous cholesterol; 2) increasing the concentration of cholesterol in outer and inner membrane when added to mitochondria with exogenous cholesterol; 3) increasing the rate of transport of cholesterol from outer membrane to inner membrane when the two membranes are incubated together in an aqueous buffer and subsequently separated by centrifugation; and 4) increasing the proportion of molecules of C27 side-chain cleavage P-450 that are bound to the substrate cholesterol. The protein is homogeneous according to two-dimensional polyacrylamide gels, shows a molecular weight of 8200 and is therefore referred to as 8.2 K. It is proposed that 8.2 K may be involved in the regulation of steroid synthesis in bovine fasciculata cells, possibly by stimulating entry of cholesterol into the outer membrane and by altering the intramitochondrial distribution of this substrate.
Department of Pharmacology, Jikei University School of Medicine, Tokyo, Japan.
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Yanagibashi
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Ohno
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Kawamura
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PF
Hall
D000302:Adrenal Cortex / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport; D002352:Carrier Proteins / Q000302:isolation & purification / Q000378:metabolism*; D002417:Cattle; D002784:Cholesterol / Q000378:metabolism*; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000378:metabolism; D007425:Intracellular Membranes / Q000378:metabolism*; D007700:Kinetics; D026901:Membrane Transport Proteins; D008928:Mitochondria / Q000378:metabolism*; D008970:Molecular Weight; D011284:Pregnenolone / Q000096:biosynthesis
C057215:8.2K CTP protein, Bos taurus; D002352:Carrier Proteins; D026901:Membrane Transport Proteins; D011284:Pregnenolone; D002784:Cholesterol; D002786:Cholesterol Side-Chain Cleavage Enzyme