Regulation of endoplasmic reticulum cholesterol by plasma membrane cholesterol.
It is found that ER cholesterol in resting human fibroblasts comprised approximately 0.5% of the cell total, and brief exposure of cells to the oxysterol, 25-hydroxycholesterol, elevated and linearized the J-curve, increasing ER cholesterol at all values of cell cholesterol.
Plasma membranes contain half the phospholipid and 90% of the cholesterol and sphingomyelin in cultured human fibroblasts.
- Y. Lange, M. Swaisgood, B. Ramos, T. Steck
- Biology, ChemistryJournal of Biological Chemistry
- 5 March 1989
It is concluded that the compartment marked by 5' nucleotidase in cultured human fibroblasts contains approximately 90% of the two named lipids and half the cell phospholipid phosphorus.
Cyclic 3', 5'-AMP relay in dictyostelium discoideum. IV. Recovery of the cAMP signaling response after adaptation to cAMP
The data reported here imply that both the rate of rise in the adaptation process and the final level reached depend on the occupancy of cAMP surface receptors and that the decay of adaptation when external cAMP is removed proceeds with first-order kinetics.
Cyclic 3', 5'-AMP relay dictyostelium discoideum. V. Adaptation of the cAMP signaling response during cAMP stimulation
The results support a working hypothesis in which the occupancy of surface cAMP receptors leads to changes in two opposing cellular processes, excitation and adaptation, that control the activity of D. discoideum adenylate cyclase.
Quantitation of the Pool of Cholesterol Associated with Acyl-CoA:Cholesterol Acyltransferase in Human Fibroblasts*
The pool of cholesterol esterified in vitro appears to reflect that associated with the ER in vivo, since several of the mechanisms keeping cell cholesterol under tight feedback control are themselves located in the ER, and this pool might not only be regulated physiologically, but could, in turn, help to regulate homeostatic effector pathways.
Cholesterol homeostasis. Modulation by amphiphiles.
On the mechanism of transfer of cholesterol between human erythrocytes and plasma.
The uptake of nucleosides by cells in culture. I. Inhibition by heterologous nucleosides.
Role of the reticulum in the stability and shape of the isolated human erythrocyte membrane
It is concluded that the reticulum is a durable, flexible, and elastic network which assumes and stabilizes the contour of the membrane but is not responsible for its crenation.
Analysis of the Ribonucleic Acid of Murine Leukemia Virus
These experiments demonstrate that the vRNA of MLV is held in a specific conformation by hydrogen bonds distributed over a large part of the molecule.