Cell surface lipids and adhesion. I. The effects of lysophosphatidyl compounds, phospholipase A2 and aggregation-inhibiting protein

1975 ◽  
Vol 18 (3) ◽  
pp. 347-356
Author(s):  
A.S. Curtis ◽  
J. Campbell ◽  
F.M. Shaw

Aggregation-inhibiting protein (AIP: Curtis & Greaves, 1965), which diminishes the adhesiveness of cells, particularly at low temperatures, is identified in the present paper as phospholipase A2 (EC. 3.1.1.4). Our reasons for this identification are because phospholipase activity parallels AIP activity on cell adhesion, and because various inhibitors and sera act in a parallel manner on adhesion in the presence of AIP or phospholipase. We suggest that the enzyme acts on adhesion by producing lysolecithin and other lysolipids in the plasmalemma. Addition of lysolipids diminishes cell adhesion in a manner similar to phospholipase A. Incubation of cells in Hanks' medium at 37 degrees C has a parallel effect. Conditions which would be expected to stimulate reacylation of lysolipids in the plasmalemma, i.e. incubation of cells in the external presence of CoA, ATP and a fatty acid, lead to a recovery or maintenance of adhesion after or during Hanks' incubation at 37 degrees C. All these results suggest that lipid components of the cell, probably in the plasmalemma, are of importance in adhesion. The results are discussed in relation to the long-standing controversy about the effects of low temperatures and trypsinization on cell adhesion, for phospholipase treatment of cells affects adhesion in a manner similar to trypsinization.

1975 ◽  
Vol 18 (3) ◽  
pp. 357-373
Author(s):  
A.S. Curtis ◽  
F.M. Shaw ◽  
V.M. Spires

The preceding paper showed that those conditions that ought to stimulate reacylation of lysolipids in cells can increase cell adhesions. Similarly we found that conditions that would be expected to lead to the accumulation of lysolipids in the cell surface diminish cell adhesion. This paper reports on the answers to the following questions. (1) Is reacylation of lysolipids in the cells stimulated by an external supply of CoA, ATP and a fatty acid? (2) Does this reacylation lead to the incorporation of exogenous fatty acid in the plasmlemma? (3) What range of fatty acids can be incorporated into the plasmalemma and into what compounds? (4) Does the plasmalemma contain the enzyme systems to effect this turnover, namely phospholipase A2, a CoA-ligase and an appropriate acyl transferase(s)? (5) Do lysolipids accumulate in the plasmalemma under conditions which diminish cell adhesion? We find that saturated fatty acids in the range C14–C18, and some unsaturated fatty acids are incorporated into the plasmalemmae of these neural retina cells. About 20% of the plasmlemma content of fatty acids can be turned over in 30′. Incorporation is mainly into phosphatidyl choline, serine and ethanolamine in both R1 and R2 positions. The plasmalemmae contain the enzymes to effect the turnover. Isolated plasmalemmae are active in this turnover. Incubation of the plasmalemmae with phospholipase A2 leads to an accumulation of lysolipids. Very low levels of phospholipase stimulate turnover, possibly endogenous phospholipase activity is the rate-limiting step in the system. These findings are discussed in relation to the possible mechanisms by which lipids might affect adhesion.


1998 ◽  
Vol 66 (5) ◽  
pp. 1885-1890 ◽  
Author(s):  
Zuncai Wang ◽  
Cyril Clarke ◽  
Kenneth Clinkenbeard

ABSTRACT Exposure of bovine neutrophils to Pasteurella haemolytica leukotoxin (LKT) stimulates the production of leukotriene B4 (LTB4), which is believed to be an important chemotactic agent in the development of acute fibrinopurulent pneumonic infection in cattle. The involvement of phospholipase A2 (PLA2) in LKT-induced synthesis of LTB4 was studied by using bovine neutrophils labeled with 3H-arachidonate ([3H]AA). Incubation of isolated neutrophils with [3H]AA resulted in incorporation of radioactivity in the PLA2 substrates phosphatidylcholine, phosphatidylinositol, and phosphatidylethanolamine. Exposure of radiolabeled neutrophils to LKT caused concentration- and time-dependent release of radioactivity and redistribution of radioactivity in neutrophil membranes consistent with utilization of phosphoglyceride substrate and release of free fatty acid and eicosanoid products. These LKT-induced effects could be inhibited by pretreatment with arachidonyl trifluoromethyl ketone, an inhibitor of type IV cytoplasmic PLA2, and were dependent on extracellular calcium. These results support the conclusion that LKT-induced synthesis of LTB4 involves a calcium-mediated increase in PLA2 activity.


1999 ◽  
Vol 340 (1) ◽  
pp. 237-243 ◽  
Author(s):  
Shilpa KADAM ◽  
Rita MULHERKAR

Enhancing factor (EF), a molecule that increases the binding of epidermal growth factor (EGF) to A431 cells, was first isolated in our laboratory from mouse intestines, and subsequently shown to be a secretory form of phospholipase A2 (PLA2) [Mulherkar, Rao, Wagle, Patki and Deo (1993) Biochem. Biophys. Res. Commun. 195, 1254-1263]. We had proposed earlier that EF increases the binding of EGF by first binding to its own cell-surface receptor [identified as a 100 kDa molecule; Mulherkar and Deo (1986) J. Cell. Physiol. 127, 183-188], and then by creating a binding site for EGF. However, due to its PLA2 activity, there was a possibility that EF, by its phospholipase activity could be unmasking cryptic EGF receptors on the cell surface, thereby increasing the number of binding sites for EGF. To test whether enhancing activity and phospholipase activity are independent of each other, a series of mutations were created using the full-length EF cDNA as a template, expressed in 293 cells and the mutant recombinant proteins checked for EF as well as PLA2 activities. Our studies have shown that one of the mutant EF proteins, lacking PLA2 activity, retains EF activity. This demonstrates unambiguously that EF and PLA2 activities are two independent activities in the same molecule. Mutation in the Ca2+-binding loop resulted in loss of EF activity, thereby demonstrating that EF activity is Ca2+-dependent. The N-terminal region of the EF molecule appears to be crucial for the enhancing activity.


Author(s):  
Alexander Flegler ◽  
Vanessa Kombeitz ◽  
André Lipski

AbstractListeria monocytogenes is a food-borne pathogen with the ability to grow at low temperatures down to − 0.4 °C. Maintaining cytoplasmic membrane fluidity by changing the lipid membrane composition is important during growth at low temperatures. In Listeria monocytogenes, the dominant adaptation effect is the fluidization of the membrane by shortening of fatty acid chain length. In some strains, however, an additional response is the increase in menaquinone content during growth at low temperatures. The increase of this neutral lipid leads to fluidization of the membrane and thus represents a mechanism that is complementary to the fatty acid-mediated modification of membrane fluidity. This study demonstrated that the reduction of menaquinone content for Listeria monocytogenes strains resulted in significantly lower resistance to temperature stress and lower growth rates compared to unaffected control cultures after growth at 6 °C. Menaquinone content was reduced by supplementation with aromatic amino acids, which led to a feedback inhibition of the menaquinone synthesis. Menaquinone-reduced Listeria monocytogenes strains showed reduced bacterial cell fitness. This confirmed the adaptive function of menaquinones for growth at low temperatures of this pathogen.


RSC Advances ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 3390-3398
Author(s):  
S. Mallik ◽  
R. Prasad ◽  
K. Das ◽  
P. Sen

Cell-surface sphingomyelin (SM) inhibits binary and ternary complex activity of blood coagulation.


2021 ◽  
Vol 15 (1) ◽  
pp. 1-17
Author(s):  
Sarah Alsharif ◽  
Pooja Sharma ◽  
Karina Bursch ◽  
Rachel Milliken ◽  
Van Lam ◽  
...  

1993 ◽  
Vol 13 (4) ◽  
pp. 2554-2563 ◽  
Author(s):  
D Wojciechowicz ◽  
C F Lu ◽  
J Kurjan ◽  
P N Lipke

alpha-Agglutinin is a cell adhesion glycoprotein expressed on the cell wall of Saccharomyces cerevisiae alpha cells. Binding of alpha-agglutinin to its ligand a-agglutinin, expressed by a cells, mediates cell-cell contact during mating. Analysis of truncations of the 650-amino-acid alpha-agglutinin structural gene AG alpha 1 delineated functional domains of alpha-agglutinin. Removal of the C-terminal hydrophobic sequence allowed efficient secretion of the protein and loss of cell surface attachment. This cell surface anchorage domain was necessary for linkage to a glycosyl phosphatidylinositol anchor. A construct expressing the N-terminal 350 amino acid residues retained full a-agglutinin-binding activity, localizing the binding domain to the N-terminal portion of alpha-agglutinin. A 278-residue N-terminal peptide was inactive; therefore, the binding domain includes residues between 278 and 350. The segment of alpha-agglutinin between amino acid residues 217 and 308 showed significant structural and sequence similarity to a consensus sequence for immunoglobulin superfamily variable-type domains. The similarity of the alpha-agglutinin-binding domain to mammalian cell adhesion proteins suggests that this structure is a highly conserved feature of adhesion proteins in diverse eukaryotes.


1993 ◽  
Vol 264 (1) ◽  
pp. F149-F157 ◽  
Author(s):  
J. Gailit ◽  
D. Colflesh ◽  
I. Rabiner ◽  
J. Simone ◽  
M. S. Goligorsky

Tubular obstruction by detached renal tubular epithelial cells is a major cause of oliguria in acute renal failure. Viable renal tubular cells can be recovered from urine of patients with acute tubular necrosis, suggesting a possible defect in cell adhesion to the basement membrane. To study this process of epithelial cell desquamation in vitro, we investigated the effect of nonlethal oxidative stress on the integrin adhesion receptors of the primate kidney epithelial cell line BS-C-1. Morphological and functional studies of cell adhesion properties included the following: interference reflection microscopy, intravital confocal microscopy and immunocytochemistry, flow cytometric analysis of integrin receptor abundance, and cell-matrix attachment assay. High levels of the integrin subunits alpha 3, alpha v, and beta 1 were detected on the cell surface by fluorescence-activated cell sorting (FACS) analysis, as well as lower levels of alpha 1, alpha 2, alpha 4, alpha 5, alpha 6, and beta 3. Exposure of BS-C-1 cells to nonlethal oxidative stress resulted in the disruption of focal contacts, disappearance of talin from the basal cell surface, and in the redistribution of integrin alpha 3-subunits from predominantly basal location to the apical cell surface. As measured in a quantitative cell attachment assay, oxidative stress decreased BS-C-1 cell adhesion to type IV collagen, laminin, fibronectin, and vitronectin. Defective adhesion was not associated with a loss of alpha 3-, alpha 4-, or alpha v-integrin subunits from the cell surface.(ABSTRACT TRUNCATED AT 250 WORDS)


Biochemistry ◽  
1994 ◽  
Vol 33 (38) ◽  
pp. 11598-11607 ◽  
Author(s):  
Zhen Shen ◽  
Shih-Kwang Wu ◽  
Wonhwa Cho

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