Biomaterial Database

Dietary cholesterol, membrane cholesterol and cholesterol synthesis. 1991

C Lutton

Laboratoire de Physiologie de la Nutrition, Université Paris Sud, Orsay, France.

After describing the main steps of cholesterol biosynthesis the author recalls that the cholesterogenesis rate is feedback-inhibited by dietary cholesterol and examines the various processes of modulation. Hydroxy-3-methylglutaryl (HMG) CoA reductase, the key rate-limiting enzyme, is a 97 kDa endoplasmic reticulum glycoprotein, anchored 7-fold in this membrane. The N-terminal membrane-bound domain plays a fundamental role in the modulation of reductase activity. This modulation is essentially mediated by decreased gene transcription and enhanced degradation of the protein. The possible modulation by a bicyclic cascade system involving phosphorylation (inactivation) and dephosphorylation (activation) of reductase does not seem to play an essential role in vivo. Finally, recent data show that the lipid composition (C/P molar ratio) of some reticular membranes (fibroblasts, for example) can strongly modulate the activity of this ubiquitous enzyme.

UI	MeSH Term	Description	Entries
D008563	Membrane Lipids	Lipids, predominantly phospholipids, cholesterol and small amounts of glycolipids found in membranes including cellular and intracellular membranes. These lipids may be arranged in bilayers in the membranes with integral proteins between the layers and peripheral proteins attached to the outside. Membrane lipids are required for active transport, several enzymatic activities and membrane formation.	Cell Membrane Lipid,Cell Membrane Lipids,Membrane Lipid,Lipid, Cell Membrane,Lipid, Membrane,Lipids, Cell Membrane,Lipids, Membrane,Membrane Lipid, Cell,Membrane Lipids, Cell
D010766	Phosphorylation	The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.	Phosphorylations
D002784	Cholesterol	The principal sterol of all higher animals, distributed in body tissues, especially the brain and spinal cord, and in animal fats and oils.	Epicholesterol
D002791	Cholesterol, Dietary	Cholesterol present in food, especially in animal products.	Dietary Cholesterol
D005246	Feedback	A mechanism of communication within a system in that the input signal generates an output response which returns to influence the continued activity or productivity of that system.	Feedbacks
D006903	Hydroxymethylglutaryl CoA Reductases	Enzymes that catalyze the reversible reduction of alpha-carboxyl group of 3-hydroxy-3-methylglutaryl-coenzyme A to yield MEVALONIC ACID.	HMG CoA Reductases,3-Hydroxy-3-methylglutaryl CoA Reductase,HMG CoA Reductase,Hydroxymethylglutaryl CoA Reductase,3 Hydroxy 3 methylglutaryl CoA Reductase,CoA Reductase, 3-Hydroxy-3-methylglutaryl,Reductase, 3-Hydroxy-3-methylglutaryl CoA
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D066298	In Vitro Techniques	Methods to study reactions or processes taking place in an artificial environment outside the living organism.	In Vitro Test,In Vitro Testing,In Vitro Tests,In Vitro as Topic,In Vitro,In Vitro Technique,In Vitro Testings,Technique, In Vitro,Techniques, In Vitro,Test, In Vitro,Testing, In Vitro,Testings, In Vitro,Tests, In Vitro,Vitro Testing, In