TY - JOUR
T1 - Regulation of 3 hydroxy 3 methylglutaryl coenzyme A reductase activity in cultured human fibroblasts. Comparison of cells from a normal subject and from a patient with homozygous familial hypercholesterolemia
AU - Brown, M. S.
AU - Dana, S. E.
AU - Goldstein, J. L.
N1 - Copyright:
Copyright 2004 Elsevier B.V., All rights reserved.
PY - 1974
Y1 - 1974
N2 - The activity of 3 hydroxy 3 methylglutaryl coenzyme A reductase, the rate controlling enzyme in cholesterol biosynthesis, is suppressed in normal fibroblasts cultured in medium containing whole serum. The factor responsible for this suppression was localized to the low density and very low density lipoproteins, but was not found in high density lipoproteins. Whole serum from a patient with abetalipoproteinemia, which is deficient in apolipoprotein B (the protein common to low density and very low density lipoproteins), did not suppress the activity of 3 hydroxy 3 methylglutaryl coenzyme A reductase. Since cholesterol itself was able to suppress enzyme activity when added to cells in a non lipoprotein form, the data indicate that low density and very low density lipoproteins reduce enzyme activity by delivering cholesterol to the cell. The cholesterol, in turn, acts to inhibit the synthesis of new 3 hydroxy 3 methylglutaryl coenzyme A reductase molecules. Cultured cells from a homozygote with the disorder familial hypercholesterolemia, which showed a nearly complete failure of suppression of 3 hydroxy 3 methylglutaryl coenzyme A reductase activity by low density or very low density lipoproteins, synthesized enzyme molecules at a rate nearly 60 times greater than that of normal cells. But when cholesterol was administered to these mutant cells in a nonlipoprotein form, it was able to exert a full inhibitory effect on 3 hydroxy 3 methylglutaryl coenzyme A reductase activity, suggesting that the primary defect in these cells resides in the transfer of cholesterol from extracellular low density lipoproteins to its presumed site of action on or within the cell. In further studies of the regulation of 3 hydroxy 3 methylglutaryl coenzyme A reductase, enzyme activity in normal and mutant fibroblasts was shown to be stimulated by several factors in human serum, one of which is insulin.
AB - The activity of 3 hydroxy 3 methylglutaryl coenzyme A reductase, the rate controlling enzyme in cholesterol biosynthesis, is suppressed in normal fibroblasts cultured in medium containing whole serum. The factor responsible for this suppression was localized to the low density and very low density lipoproteins, but was not found in high density lipoproteins. Whole serum from a patient with abetalipoproteinemia, which is deficient in apolipoprotein B (the protein common to low density and very low density lipoproteins), did not suppress the activity of 3 hydroxy 3 methylglutaryl coenzyme A reductase. Since cholesterol itself was able to suppress enzyme activity when added to cells in a non lipoprotein form, the data indicate that low density and very low density lipoproteins reduce enzyme activity by delivering cholesterol to the cell. The cholesterol, in turn, acts to inhibit the synthesis of new 3 hydroxy 3 methylglutaryl coenzyme A reductase molecules. Cultured cells from a homozygote with the disorder familial hypercholesterolemia, which showed a nearly complete failure of suppression of 3 hydroxy 3 methylglutaryl coenzyme A reductase activity by low density or very low density lipoproteins, synthesized enzyme molecules at a rate nearly 60 times greater than that of normal cells. But when cholesterol was administered to these mutant cells in a nonlipoprotein form, it was able to exert a full inhibitory effect on 3 hydroxy 3 methylglutaryl coenzyme A reductase activity, suggesting that the primary defect in these cells resides in the transfer of cholesterol from extracellular low density lipoproteins to its presumed site of action on or within the cell. In further studies of the regulation of 3 hydroxy 3 methylglutaryl coenzyme A reductase, enzyme activity in normal and mutant fibroblasts was shown to be stimulated by several factors in human serum, one of which is insulin.
UR - http://www.scopus.com/inward/record.url?scp=0015989544&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0015989544&partnerID=8YFLogxK
M3 - Article
C2 - 4359767
AN - SCOPUS:0015989544
SN - 0021-9258
VL - 249
SP - 789
EP - 796
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 3
ER -