scholarly journals The role of the plasma membrane in fatty acid uptake by rat liver parenchymal cells

1971 ◽  
Vol 123 (5) ◽  
pp. 837-844 ◽  
Author(s):  
J. D. Wright ◽  
C. Green
Keyword(s):  
Plasma Membrane ◽  
Palmitic Acid ◽  
Membrane Fraction ◽  
Specific Radioactivity ◽  
Fatty Acid Uptake ◽  
Acid Uptake ◽  
Liver Parenchymal ◽  
Plasma Membrane Fraction ◽  
Parenchymal Cells

1. Suspensions of isolated rat liver parenchymal cells incorporate [14C]palmitic acid into glycerides at about 40% of the rate obtained with liver slices. 2. At short time-intervals most of the incorporation is into phosphatidylcholine and this is recovered mainly in the plasma-membrane fraction. 3. At later times (5min to 2h) the [14C]palmitic acid is mainly found in triglyceride, but this is not recovered in the plasma-membrane fraction. 4. Addition of lysophosphatidylcholine increases incorporation of palmitic acid into both phosphatidylcholine and triglyceride, with maximum effect at about 0.1mm. 5. In vivo, 1min after injection of [14C]palmitic acid, radioactive phosphatidylcholine is concentrated in the plasma-membrane fraction, but the proportion present in this fraction declines rapidly. 6. The phosphatidylcholine of the plasma-membrane fraction has, at 1min after injection, a specific radioactivity 30-fold greater than that of the whole tissue. 7. This phosphatidylcholine reaches its maximum specific radioactivity before the tissue phosphatidic acid or diglyceride. 8. The phosphatidylcholine of the plasma-membrane fraction has a very rapid turnover. 9. It is proposed that the rapid formation of phospholipids in the plasma membrane is by acylation of their lyso-derivatives and the role of this process in fatty acid uptake is discussed.

scholarly journals Critical role of sulfhydryl group(s) in ATP-dependent Ca2+ sequestration by the plasma membrane fraction from rat liver

FEBS Letters ◽  
1983 ◽  
Vol 163 (1) ◽  
pp. 136-139 ◽  
Author(s):  
Giorgio Bellomo ◽  
Francesca Mirabelli ◽  
Plinio Richelmi ◽  
Sten Orrenius
Keyword(s):  
Plasma Membrane ◽  
Rat Liver ◽  
Membrane Fraction ◽  
Critical Role ◽  
Sulfhydryl Group ◽  
Plasma Membrane Fraction

scholarly journals ACYLATION OF LYSOPHOSPHATIDES BY PLASMA MEMBRANE FRACTIONS OF RAT LIVER

1968 ◽  
Vol 39 (1) ◽  
pp. 185-192 ◽  
Author(s):  
Yechezkiel Stein ◽  
Christopher Widnell ◽  
Olga Stein
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Palmitic Acid ◽  
Rat Liver ◽  
Membrane Fraction ◽  
Specific Activity ◽  
Acylation Reaction ◽  
Plasma Membrane Fraction ◽  
Enzyme Markers

The plasma membrane fraction of rat liver was isolated and incubated with labeled lysophosphatides in the presence of cofactors; the acylation of lysolecithin to lecithin by the fraction was compared to that of the rough and smooth microsomes. The purity of the isolated fractions was ascertained by enzyme markers and electron microscopy, and the maximal contamination of the plasma membrane fraction by microsomes did not exceed 20%. Under conditions at which the reaction was proportional to the amount of enzyme used, the plasma membrane had a specific activity similar to that of the smooth and rough microsomes. With doubly labeled lysolecithin (containing palmitic acid-14C and choline-3H) it was shown that the lecithin formed retained the same ratio of the two labels, which indicated that lysolecithin was converted to lecithin through an acylation reaction. The newly formed lecithin was shown to be bound to the plasma membrane fraction; this suggested that it is incorporated into the structure of the membrane itself.

scholarly journals Isolation of plasma membrane from protoplasts of Lolium multiflorum (ryegrass) endosperm cells

1982 ◽  
Vol 205 (3) ◽  
pp. 511-519 ◽  
Author(s):  
A Schibeci ◽  
G B Fincher ◽  
B A Stone ◽  
A B Wardrop
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Membrane Fraction ◽  
Plasma Membranes ◽  
Lolium Multiflorum ◽  
Immunoglobulin A ◽  
Specific Radioactivity ◽  
Centrifugal Forces ◽  
Myeloma Protein ◽  
Plasma Membrane Fraction

Plasma membranes have been isolated from protoplasts of suspension-cultured ryegrass (Lolium multiflorum) endosperm cells. The protoplast membrane is coated before cell disruption with murine myeloma protein J539, a galactose-binding immunoglobulin A. The plasma membrane is labelled with 125I by using chemically or enzymically catalysed iodination techniques, or, more conveniently, by using 125I-labelled myeloma protein J539, which enables the membrane to be simultaneously coated and labelled. Protoplast lysis is effected by gentle mechanical means after swelling in hypo-osmotic medium. The plasma-membrane fraction is recovered at low centrifugal forces by fractionation of cell lysates on a discontinuous sucrose/sorbitol gradient. The plasma-membrane fraction is enriched 96-fold on a protein basis with respect to the specific radioactivity of 125I-labeled myeloma protein J539 in the homogenate. Electron microscopy showed long membrane profiles often associated with one another.

scholarly journals Calcium-dependent fusion of the plasma membrane fraction from human neutrophils with liposomes

1990 ◽  
Vol 1025 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Joseph W. Francis ◽  
James E. Smolen ◽  
Kenneth J. Balazovich ◽  
Rebecca R. Sandborg ◽  
Laurence A. Boxer
Keyword(s):  
Plasma Membrane ◽  
Membrane Fraction ◽  
Human Neutrophils ◽  
Plasma Membrane Fraction ◽  
Calcium Dependent

Association of the hepatic IP3 receptor with the plasma membrane: relevance to mode of action

1993 ◽  
Vol 265 (6) ◽  
pp. C1588-C1596 ◽  
Author(s):  
L. Feng ◽  
N. Kraus-Friedmann
Keyword(s):  
Plasma Membrane ◽  
Membrane Fraction ◽  
Ip3 Receptors ◽  
Ip3 Receptor ◽  
Plasma Membrane Fraction ◽  
T Lymphoma Cells ◽  
T Lymphoma ◽  
Triton X ◽  
Brain Receptor ◽  
The Brain

Studies were carried out to characterize the interaction between inositol 1,4,5-trisphosphate (IP3) receptors and the plasma membrane fraction. Extraction of the membranes with the nonionic detergents Nonidet P-40 and Triton X-100, followed by centrifugation at 100,000 g, resulted in the doubling of the IP3 receptor in the pellets, whereas no detectable binding was found in the supernatants. These data indicate that the detergents did not solubilize the receptor, that it remained associated with membrane particles, and that it is likely to be associated with the cytoskeleton. The cytoskeleton proteins actin, ankyrin, and spectrin were identified in the plasma membrane fraction. However, comparison of the amount of these proteins in different fractions of the detergent, or otherwise treated plasma membrane fractions, showed no direct correlation between the presence of any of these proteins in the plasma membrane fraction and their ability to bind [3H]IP3. This is in contrast to the brain and T-lymphoma cells in which the IP3 receptor is attached to ankyrin (L. Y. W. Bourguigon, H. Jin, N. Iida, N. R. Brandt, and S. H. Zhang. J. Biol. Chem. 268: 6477-6486, 1993; and S. K. Joseph and S. Samanta. J. Biol. Chem 268: 6477-6486, 1993). Thus the hepatic IP3 receptor, which is different from the brain receptor, might attach to the cytoskeleton by anchoring to a different protein. Because cytochalasin D treatment of livers diminishes the ability of IP3 to raise cytosolic free Ca2+ levels, the attachment of the IP3 receptor to the cytoskeleton seems to involve an association with microfilaments.

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