scholarly journals Cholesterol movement between the plasma membrane and the cholesteryl ester droplets of cultured Leydig tumour cells

1990 ◽  
Vol 271 (3) ◽  
pp. 809-814 ◽  
Author(s):  
L Nagy ◽  
D A Freeman
Keyword(s):  
Plasma Membrane ◽  
Cholesteryl Ester ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Tumour Cells ◽  
Membrane Cholesterol ◽  
Membrane Turnover ◽  
Epidermal Growth ◽  
Plasma Membrane Cholesterol ◽  
Stimulation Of

The present studies characterize the turnover of plasma membrane cholesterol in MA-10 Leydig tumour cells. Plasma membrane cholesterol of MA-10 cells was slowly internalized and converted into cholesteryl ester. Low-density lipoprotein (LDL) stimulated, in a dose- and time-dependent fashion, plasma membrane cholesterol conversion into intracellular esters. Stimulation of membrane internalization was not simply the consequence of accelerated uptake of membrane with LDL, since binding and internalization of epidermal growth factor and transferrin had no effect on turnover of plasma membrane cholesterol. The protein of LDL is unimportant as well, since delipidated LDL had no effect on membrane turnover. The action of LDL on cholesterol turnover was explained entirely by its contribution to cholesteryl ester stores. The degree of plasma membrane cholesterol internalization and esterification was directly proportional to the size of cellular ester stores.

scholarly journals Distribution of membrane cholesterol of adrenal cortical cells after corticotropin stimulation

1983 ◽  
Vol 214 (2) ◽  
pp. 561-567 ◽  
Author(s):  
O M Conneely ◽  
J M Greene ◽  
D R Headon ◽  
J Hsiao ◽  
F Ungar
Keyword(s):  
Plasma Membrane ◽  
Cholesteryl Ester ◽  
Membrane Cholesterol ◽  
Cortical Cells ◽  
Cholesterol Levels ◽  
Adrenal Cortical Cells ◽  
Hydrolysis Of ◽  
Plasma Membrane Cholesterol ◽  
Corticotropin Stimulation ◽  
Stimulation Of

Membrane cholesterol in adrenal cortical cells is enriched in the plasma membrane. Stimulation of isolated adrenal cortical cells with corticotropin leads to the production of corticosterone. At high levels of corticotropin, cholesterol for corticosterone synthesis arises by hydrolysis of cellular cholesteryl ester, whereas at lower levels of corticotropin cholesteryl ester levels are unchanged from control values and there is a decrease in plasma-membrane cholesterol levels.

scholarly journals Macrophage Plasma Membrane Cholesterol Contributes to Brucella abortus Infection of Mice

2002 ◽  
Vol 70 (9) ◽  
pp. 4818-4825 ◽  
Author(s):  
Masahisa Watarai ◽  
Sou-ichi Makino ◽  
Makoto Michikawa ◽  
Katsuhiko Yanagisawa ◽  
Shigeru Murakami ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Bacterial Infection ◽  
Brucella Abortus ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Membrane Cholesterol ◽  
Intracellular Replication ◽  
Niemann Pick ◽  
Deficient Mice ◽  
Plasma Membrane Cholesterol

ABSTRACT Brucella abortus is a facultative intracellular bacterium capable of surviving inside macrophages. Intracellular replication of B. abortus requires the VirB complex, which is highly similar to conjugative DNA transfer systems. In this study, we show that plasma membrane cholesterol of macrophages is required for the VirB-dependent internalization of B. abortus and also contributes to the establishment of bacterial infection in mice. The internalization of B. abortus was accelerated by treating macrophages with acetylated low-density lipoprotein (acLDL). Treatment of acyl coenzyme A:cholesterol acyltransferase inhibitor, HL-004, to macrophages preloaded with acLDL accelerated the internalization of B. abortus. Ketoconazole, which inhibits cholesterol transport from lysosomes to the cell surface, inhibited the internalization and intracellular replication of B. abortus in macrophages. The Niemann-Pick C1 gene (NPC1), the gene for Niemann-Pick type C disease, characterized by an accumulation of cholesterol in most tissues, promoted B. abortus infection. NPC1-deficient mice were resistant to the bacterial infection. Molecules associated with cholesterol-rich microdomains, “lipid rafts,” accumulate in intracellular vesicles of macrophages isolated from NPC1-deficient mice, and the macrophages yielded no intracellular replication of B. abortus. Thus, trafficking of cholesterol-associated microdomains controlled by NPC1 is critical for the establishment of B. abortus infection.

scholarly journals Three pools of plasma membrane cholesterol and their relation to cholesterol homeostasis

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Akash Das ◽  
Michael S Brown ◽  
Donald D Anderson ◽  
Joseph L Goldstein ◽  
Arun Radhakrishnan
Keyword(s):  
Plasma Membrane ◽  
Regulatory Mechanism ◽  
Low Density Lipoprotein ◽  
Human Fibroblasts ◽  
Density Lipoprotein ◽  
Cholesterol Homeostasis ◽  
Mutant Form ◽  
Perfringolysin O ◽  
Cholesterol Levels ◽  
Plasma Membrane Cholesterol

When human fibroblasts take up plasma low density lipoprotein (LDL), its cholesterol is liberated in lysosomes and eventually reaches the endoplasmic reticulum (ER) where it inhibits cholesterol synthesis by blocking activation of SREBPs. This feedback protects against cholesterol overaccumulation in the plasma membrane (PM). But how does ER know whether PM is saturated with cholesterol? In this study, we define three pools of PM cholesterol: (1) a pool accessible to bind 125I-PFO*, a mutant form of bacterial Perfringolysin O, which binds cholesterol in membranes; (2) a sphingomyelin(SM)-sequestered pool that binds 125I-PFO* only after SM is destroyed by sphingomyelinase; and (3) a residual pool that does not bind 125I-PFO* even after sphingomyelinase treatment. When LDL-derived cholesterol leaves lysosomes, it expands PM's PFO-accessible pool and, after a short lag, it also increases the ER's PFO-accessible regulatory pool. This regulatory mechanism allows cells to ensure optimal cholesterol levels in PM while avoiding cholesterol overaccumulation.

scholarly journals Stimulation of low-density lipoprotein uptake in HepG2 cells by epidermal growth factor via a tyrosine kinase-dependent, but protein kinase C-independent, mechanism

1994 ◽  
Vol 298 (3) ◽  
pp. 579-584 ◽  
Author(s):  
A Graham ◽  
L J Russell
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Tyrosine Kinase ◽  
Hepg2 Cells ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Kinase C ◽  
Ldl Uptake ◽  
Epidermal Growth ◽  
Stimulation Of

Epidermal growth factor (EGF), a potent mitogenic polypeptide, stimulated the uptake and degradation of [3H]sucrose-labelled low-density lipoprotein (LDL) by HepG2 cells. The increase in LDL uptake was prevented by the presence of the tyrosine kinase inhibitor genistein. Activation of protein kinase C with phorbol 12-myristate 13-acetate (PMA) also stimulated the uptake of [3H]LDL by HepG2 cells. When EGF and PMA were added together, PMA increased the response to EGF in an additive manner. The protein kinase C inhibitor Ro-31-8220 prevented the increase in LDL uptake caused by PMA, but did not affect EGF stimulation of LDL uptake. Similarly, down-regulation of protein kinase C activity by chronic treatment with PMA also did not affect the EGF stimulation of LDL uptake. These results suggest that the EGF stimulation of LDL uptake and degradation by HepG2 cells is mediated by a tyrosine kinase-dependent, but protein kinase C-independent, mechanism.

scholarly journals Monoclonal antibody detection of plasma membrane cholesterol microdomains responsive to cholesterol trafficking

2001 ◽  
Vol 42 (9) ◽  
pp. 1492-1500 ◽  
Author(s):  
Howard S. Kruth ◽  
Ina Ifrim ◽  
Janet Chang ◽  
Lia Addadi ◽  
Daniele Perl-Treves ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Plasma Membrane ◽  
Antibody Detection ◽  
Membrane Cholesterol ◽  
Cholesterol Trafficking ◽  
Plasma Membrane Cholesterol

scholarly journals Hydrolysis of cholesteryl ester in low density lipoprotein converts this lipoprotein to a liposome.

1992 ◽  
Vol 267 (7) ◽  
pp. 4992-4998
Author(s):  
F.F. Chao ◽  
E.J. Blanchette-Mackie ◽  
V.V. Tertov ◽  
S.I. Skarlatos ◽  
Y.J. Chen ◽  
...  
Keyword(s):  
Cholesteryl Ester ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Low Density ◽  
Hydrolysis Of
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