scholarly journals Phosphatidylserine exposure promotes increased adhesion in Dictyostelium Copine A mutants

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0250710
Author(s):  
Amber D. Ide ◽  
Elise M. Wight ◽  
Cynthia K. Damer
Keyword(s):  
Plasma Membrane ◽  
Cell Adhesion ◽  
Membrane Trafficking ◽  
Fluorescent Microscopy ◽  
Annexin V ◽  
Membrane Lipid ◽  
Surface Proteins ◽  
Negative Regulator ◽  
Cell Functions ◽  
Calcium Cells

The phospholipid phosphatidylserine (PS) is a key signaling molecule and binding partner for many intracellular proteins. PS is normally found on the inner surface of the cell membrane, but PS can be flipped to the outer surface in a process called PS exposure. PS exposure is important in many cell functions, yet the mechanisms that control PS exposure have not been extensively studied. Copines (Cpn), found in most eukaryotic organisms, make up a family of calcium-dependent phospholipid binding proteins. In Dictyostelium, which has six copine genes, CpnA strongly binds to PS and translocates from the cytosol to the plasma membrane in response to a rise in calcium. Cells lacking the cpnA gene (cpnA-) have defects in adhesion, chemotaxis, membrane trafficking, and cytokinesis. In this study we used both flow cytometry and fluorescent microscopy to show that cpnA- cells have increased adhesion to beads and bacteria and that the increased adhesion was not due to changes in the actin cytoskeleton or cell surface proteins. We found that cpnA- cells bound higher amounts of Annexin V, a PS binding protein, than parental cells and showed that unlabeled Annexin V reduced the increased cell adhesion property of cpnA- cells. We also found that cpnA- cells were more sensitive to Polybia-MP1, which binds to external PS and induces cell lysis. Overall, this suggests that cpnA- cells have increased PS exposure and this property contributes to the increased cell adhesion of cpnA- cells. We conclude that CpnA has a role in the regulation of plasma membrane lipid composition and may act as a negative regulator of PS exposure.

scholarly journals N-Cadherin Association with Lipid Rafts Regulates Its Dynamic Assembly at Cell-Cell Junctions in C2C12 Myoblasts

2005 ◽  
Vol 16 (5) ◽  
pp. 2168-2180 ◽  
Author(s):  
Marie Causeret ◽  
Nicolas Taulet ◽  
Franck Comunale ◽  
Cyril Favard ◽  
Cécile Gauthier-Rouvière
Keyword(s):  
Plasma Membrane ◽  
Cell Adhesion ◽  
Lipid Rafts ◽  
Membrane Lipid ◽  
Cell Junctions ◽  
Cell Contact ◽  
C2c12 Myoblasts ◽  
Cell Contacts ◽  
Dynamic Assembly ◽  
Cell Cell

Cadherins are homophilic cell-cell adhesion molecules implicated in cell growth, differentiation, and organization into tissues during embryonic development. They accumulate at cell-cell contact sites and act as adhesion-activated signaling receptors. Here, we show that the dynamic assembly of N-cadherin at cell-cell contacts involves lipid rafts. In C2C12 myoblasts, immunofluorescence and biochemical experiments demonstrate that N-cadherin present at cell-cell contacts is colocalized with lipid rafts. Disruption of lipid rafts leads to the inhibition of cell-cell adhesion and disorganization of N-cadherin–dependent cell-cell contacts without modifying the association of N-cadherin with catenins and its availability at the plasma membrane. Fluorescent recovery after photobleaching experiments demonstrate that at the dorsal plasma membrane, lipid rafts are not directly involved in the diffusional mobility of N-cadherin. In contrast, at cell-cell junctions N-cadherin association with lipid rafts allows its stabilization enabling the formation of a functional adhesive complex. We show that lipid rafts, as homophilic interaction and F-actin association, stabilize cadherin-dependent adhesive complexes. Homophilic interactions and F-actin association of N-cadherin are both required for its association to lipid rafts. We thus identify lipid rafts as new regulators of cadherin-mediated cell adhesion.

scholarly journals Effects of integrin-mediated cell adhesion on plasma membrane lipid raft components and signaling

2011 ◽  
Vol 22 (18) ◽  
pp. 3456-3464 ◽  
Author(s):  
Andrés Norambuena ◽  
Martin A. Schwartz
Keyword(s):  
Plasma Membrane ◽  
Cell Adhesion ◽  
Lipid Raft ◽  
Rho Gtpases ◽  
Cancer Metastasis ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Membrane Lipid ◽  
Cell Detachment ◽  
Suspended Cells

Anchorage dependence of cell growth, which is mediated by multiple integrin-regulated signaling pathways, is a key defense against cancer metastasis. Detachment of cells from the extracellular matrix triggers caveolin-1–dependent internalization of lipid raft components, which mediates suppression of Rho GTPases, Erk, and phosphatidylinositol 3-kinase in suspended cells. Elevation of cyclic adenosine monophosphate (cAMP) following cell detachment is also implicated in termination of growth signaling in suspended cells. Studies of integrins and lipid rafts, however, examined mainly ganglioside GM1 and glycosylphosphatidylinositol-linked proteins as lipid raft markers. In this study, we examine a wider range of lipid raft components. Whereas many raft components internalized with GM1 following cell detachment, flotillin2, connexin43, and Gαs remained in the plasma membrane. Loss of cell adhesion caused movement of many components from the lipid raft to the nonraft fractions on sucrose gradients, although flotillin2, connexin43, and H-Ras were resistant. Gαs lost its raft association, concomitant with cAMP production. Modification of the lipid tail of Gαs to increase its association with ordered domains blocked the detachment-induced increase in cAMP. These data define the effects of that integrin-mediated adhesion on the localization and behavior of a variety of lipid raft components and reveal the mechanism of the previously described elevation of cAMP after cell detachment.

Antigen recognition induces phosphatidylserine exposure on the cell surface of human CD8+ T cells

Blood ◽  
2006 ◽  
Vol 108 (13) ◽  
pp. 4094-4101 ◽  
Author(s):  
Karin Fischer ◽  
Simon Voelkl ◽  
Jana Berger ◽  
Reinhard Andreesen ◽  
Thomas Pomorski ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Microscopic Analysis ◽  
Annexin V ◽  
Membrane Lipid ◽  
Transport Proteins ◽  
Cell Contact ◽  
Immunologic Synapse

Abstract In eukaryotic cells the phospholipid phosphatidylserine (PS) is restricted to the inner plasma-membrane leaflet. This lipid asymmetry, which is maintained by the concerted action of phospholipid transport proteins, is mainly lost during apoptosis. Here, we demonstrate that primary human CD8+ cytotoxic T lymphocytes (CTLs) expose PS on T-cell receptor (TCR)–mediated antigen (Ag) recognition. In contrast to PS externalization on apoptotic cells, activation-induced PS exposure is less pronounced and reversible. Fluorescence microscopic analysis revealed that PS is distributed nonhomogenously over the plasma membrane and concentrated in membrane lipid raft domains at the immunologic synapse. By studying the activity of PS transport proteins using a fluorescence-labeled PS analogue, we found that activation of CTLs inhibited the flippase-mediated inward-directed PS transport without affecting the outward transport. Shielding of exposed PS by annexin V protein during Ag recognition diminished cytokine secretion, activation, and cell-to-cell clustering of Ag-specific CTLs. In summary, our data demonstrate for the first time that externalized PS on Ag-stimulated CTLs is linked to T-cell activation and probably involved in cell-to-cell contact formation at the immunologic synapse.

scholarly journals Mesoscale Dynamics of Spectrin and Acto-Myosin shape Membrane Territories during Mechanoresponse

2019 ◽  
Author(s):  
Andrea Ghisleni ◽  
Camilla Galli ◽  
Pascale Monzo ◽  
Flora Ascione ◽  
Marc-Antoine Fardin ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Cell Adhesion ◽  
Membrane Trafficking ◽  
Cell Mechanics ◽  
Dynamic Interaction ◽  
The Other ◽  
Cell Cortex ◽  
Mesoscale Dynamics ◽  
Spectrin Cytoskeleton ◽  
Dynamic Interplay

AbstractThe spectrin cytoskeleton is a major component of the cell cortex. While ubiquitously expressed, its dynamic interaction with the other cortex components, including the plasma membrane or the acto-myosin cytoskeleton, is poorly understood. Here, we investigated how the spectrin cytoskeleton re-organizes spatially and dynamically under the membrane during changes in cell mechanics. We found spectrin and acto-myosin cytoskeletons to be spatially distinct but cooperating during mechanical challenges, such as cell adhesion and contraction, or compression, stretch and osmolarity fluctuations, creating a cohesive cortex supporting the plasma membrane. Actin territories control protrusions and contractile structures while spectrin territories concentrate in retractile zones and low-actin density/inter-contractile regions, acting as a fence to organize membrane trafficking events. We unveil here the existence of a dynamic interplay between acto-myosin and spectrin cytoskeletons necessary to support a mesoscale organization of the lipid bilayer into spatially-confined cortical territories during cell mechanoresponse.

scholarly journals Complementary mesoscale dynamics of spectrin and acto-myosin shape membrane territories during mechanoresponse

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Andrea Ghisleni ◽  
Camilla Galli ◽  
Pascale Monzo ◽  
Flora Ascione ◽  
Marc-Antoine Fardin ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Cell Adhesion ◽  
Membrane Trafficking ◽  
Cell Mechanics ◽  
Membrane Skeleton ◽  
The Other ◽  
Cell Cortex ◽  
Dynamic Interactions ◽  
Mesoscale Dynamics ◽  
Dynamic Interplay

Abstract The spectrin-based membrane skeleton is a major component of the cell cortex. While expressed by all metazoans, its dynamic interactions with the other cortex components, including the plasma membrane or the acto-myosin cytoskeleton, are poorly understood. Here, we investigate how spectrin re-organizes spatially and dynamically under the membrane during changes in cell mechanics. We find spectrin and acto-myosin to be spatially distinct but cooperating during mechanical challenges, such as cell adhesion and contraction, or compression, stretch and osmolarity fluctuations, creating a cohesive cortex supporting the plasma membrane. Actin territories control protrusions and contractile structures while spectrin territories concentrate in retractile zones and low-actin density/inter-contractile regions, acting as a fence that organize membrane trafficking events. We unveil here the existence of a dynamic interplay between acto-myosin and spectrin necessary to support a mesoscale organization of the lipid bilayer into spatially-confined cortical territories during cell mechanoresponse.

scholarly journals Protein kinase Gin4 negatively regulates flippase function and controls plasma membrane asymmetry

2015 ◽  
Vol 208 (3) ◽  
pp. 299-311 ◽  
Author(s):  
Françoise M. Roelants ◽  
Brooke M. Su ◽  
Joachim von Wulffen ◽  
Subramaniam Ramachandran ◽  
Elodie Sartorel ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Protein Kinase ◽  
Membrane Lipid ◽  
Negative Regulator ◽  
Membrane Function ◽  
Membrane Asymmetry ◽  
Growth Deficiency ◽  
Bud Emergence ◽  
P Type

Plasma membrane function requires distinct leaflet lipid compositions. Two of the P-type ATPases (flippases) in yeast, Dnf1 and Dnf2, translocate aminoglycerophospholipids from the outer to the inner leaflet, stimulated via phosphorylation by cortically localized protein kinase Fpk1. By monitoring Fpk1 activity in vivo, we found that Fpk1 was hyperactive in cells lacking Gin4, a protein kinase previously implicated in septin collar assembly. Gin4 colocalized with Fpk1 at the cortical site of future bud emergence and phosphorylated Fpk1 at multiple sites, which we mapped. As judged by biochemical and phenotypic criteria, a mutant (Fpk111A), in which 11 sites were mutated to Ala, was hyperactive, causing increased inward transport of phosphatidylethanolamine. Thus, Gin4 is a negative regulator of Fpk1 and therefore an indirect negative regulator of flippase function. Moreover, we found that decreasing flippase function rescued the growth deficiency of four different cytokinesis mutants, which suggests that the primary function of Gin4 is highly localized control of membrane lipid asymmetry and is necessary for optimal cytokinesis.

scholarly journals Plasma membrane domains enriched in cortical endoplasmic reticulum function as membrane protein trafficking hubs

2013 ◽  
Vol 24 (17) ◽  
pp. 2703-2713 ◽  
Author(s):  
Philip D. Fox ◽  
Christopher J. Haberkorn ◽  
Aubrey V. Weigel ◽  
Jenny L. Higgins ◽  
Elizabeth J. Akin ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Membrane Protein ◽  
Membrane Trafficking ◽  
Protein Trafficking ◽  
Mammalian Cells ◽  
Transmembrane Protein ◽  
Surface Proteins ◽  
Hek 293 ◽  
Cortical Endoplasmic Reticulum

In mammalian cells, the cortical endoplasmic reticulum (cER) is a network of tubules and cisterns that lie in close apposition to the plasma membrane (PM). We provide evidence that PM domains enriched in underlying cER function as trafficking hubs for insertion and removal of PM proteins in HEK 293 cells. By simultaneously visualizing cER and various transmembrane protein cargoes with total internal reflectance fluorescence microscopy, we demonstrate that the majority of exocytotic delivery events for a recycled membrane protein or for a membrane protein being delivered to the PM for the first time occur at regions enriched in cER. Likewise, we observed recurring clathrin clusters and functional endocytosis of PM proteins preferentially at the cER-enriched regions. Thus the cER network serves to organize the molecular machinery for both insertion and removal of cell surface proteins, highlighting a novel role for these unique cellular microdomains in membrane trafficking.

scholarly journals The shed ectodomain of type XIII collagen affects cell behaviour in a matrix-dependent manner

2004 ◽  
Vol 380 (3) ◽  
pp. 685-693 ◽  
Author(s):  
Marja-Riitta VÄISÄNEN ◽  
Timo VÄISÄNEN ◽  
Taina PIHLAJANIEMI
Keyword(s):  
Plasma Membrane ◽  
Cell Adhesion ◽  
Mammalian Cells ◽  
Consensus Sequence ◽  
Biologically Active ◽  
Dependent Manner ◽  
Cell Behaviour ◽  
Proprotein Convertases ◽  
Cell Functions ◽  
Type Xiii Collagen

Transmembrane type XIII collagen resides in adhesive structures of cells and tissues, and has therefore been implicated in cell adhesion and in adhesion-dependent cell functions. This collagen also exists as a soluble protein in the pericellular matrix, as the ectodomain is released from the plasma membrane by proteolytic cleavage. Analysis with various protease inhibitors led to confirmation of the furin family of proprotein convertases as the protease group responsible for the shedding of the ectodomain, cleaving at a site conforming to the consensus sequence for the proprotein convertases at the stem of the ectodomain. Both the trans-Golgi network and the plasma membrane were used as cleavage locations. Mammalian cells employed various intracellular mechanisms to modulate shedding of the ectodomain, all resulting in a similar cleavage event. Cell detachment from the underlying substratum was also found to augment the excision. The released ectodomain rendered the pericellular surroundings less supportive of cell adhesion, migration and proliferation, as seen specifically on a vitronectin substratum. Type XIII collagen ectodomain shedding thus resulted in the formation of a soluble, biologically active molecule, which eventually modulated cell behaviour in a reciprocal and substratum-specific manner. The dual existence of membrane-bound and soluble variants widens our biological understanding of type XIII collagen.

scholarly journals Membrane Lipid Composition: Effect on Membrane and Organelle Structure, Function and Compartmentalization and Therapeutic Avenues

2019 ◽  
Vol 20 (9) ◽  
pp. 2167 ◽  
Author(s):  
Doralicia Casares ◽  
Pablo V. Escribá ◽  
Catalina Ana Rosselló
Keyword(s):  
Plasma Membrane ◽  
Lipid Bilayers ◽  
Lipid Composition ◽  
Therapeutic Potential ◽  
Current Knowledge ◽  
Signal Propagation ◽  
Membrane Lipid ◽  
Membrane Lipid Composition ◽  
Cell Functions ◽  
And Function

Biological membranes are key elements for the maintenance of cell architecture and physiology. Beyond a pure barrier separating the inner space of the cell from the outer, the plasma membrane is a scaffold and player in cell-to-cell communication and the initiation of intracellular signals among other functions. Critical to this function is the plasma membrane compartmentalization in lipid microdomains that control the localization and productive interactions of proteins involved in cell signal propagation. In addition, cells are divided into compartments limited by other membranes whose integrity and homeostasis are finely controlled, and which determine the identity and function of the different organelles. Here, we review current knowledge on membrane lipid composition in the plasma membrane and endomembrane compartments, emphasizing its role in sustaining organelle structure and function. The correct composition and structure of cell membranes define key pathophysiological aspects of cells. Therefore, we explore the therapeutic potential of manipulating membrane lipid composition with approaches like membrane lipid therapy, aiming to normalize cell functions through the modification of membrane lipid bilayers.

scholarly journals Membrane Phospholipid Asymmetry in Human Thalassemia

Blood ◽  
1998 ◽  
Vol 91 (8) ◽  
pp. 3044-3051 ◽  
Author(s):  
Frans A. Kuypers ◽  
Jie Yuan ◽  
Rachel A. Lewis ◽  
L. Michael Snyder ◽  
Charles R. Kiefer ◽  
...  
Keyword(s):  
Fluorescent Microscopy ◽  
Annexin V ◽  
Membrane Lipid ◽  
Phospholipid Asymmetry ◽  
Outer Leaflet ◽  
Globin Chains ◽  
Lipid Organization ◽  
Rapid Removal ◽  
Membrane Bound ◽  
Normal Controls

Phospholipid asymmetry in the red blood cell (RBC) lipid bilayer is well maintained during the life of the cell, with phosphatidylserine (PS) virtually exclusively located in the inner monolayer. Loss of phospholipid asymmetry, and consequently exposure of PS, is thought to play an important role in red cell pathology. The anemia in the human thalassemias is caused by a combination of ineffective erythropoiesis (intramedullary hemolysis) and a decreased survival of adult RBCs in the peripheral blood. This premature destruction of the thalassemic RBC could in part be due to a loss of phospholipid asymmetry, because cells that expose PS are recognized and removed by macrophages. In addition, PS exposure can play a role in the hypercoagulable state reported to exist in severe β-thalassemia intermedia. We describe PS exposure in RBCs of 56 comparably anemic patients with different genetic backgrounds of the α- or β-thalassemia phenotype. The use of fluorescently labeled annexin V allowed us to determine loss of phospholipid asymmetry in individual cells. Our data indicate that in a number of thalassemic patients, subpopulations of red cells circulate that expose PS on their outer surface. The number of such cells can vary dramatically from patient to patient, from as low as that found in normal controls (less than 0.2%) up to 20%. Analysis by fluorescent microscopy of β-thalassemic RBCs indicates that PS on the outer leaflet is distributed either over the entire membrane or localized in areas possibly related to regions rich in membrane-bound α-globin chains. We hypothesize that these membrane sites in which iron carrying globin chains accumulate and cause oxidative damage, could be important in the loss of membrane lipid organization. In conclusion, we report the presence of PS-exposing subpopulations of thalassemic RBC that are most likely physiologically important, because they could provide a surface for enhancing hemostasis as recently reported, and because such exposure may mediate the rapid removal of these RBCs from the circulation, thereby contributing to the anemia.

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