scholarly journals Insulin-Induced Endothelial Cell Cortical Actin Filament Remodeling: A Requirement for Trans-Endothelial Insulin Transport

2012 ◽  
Vol 26 (8) ◽  
pp. 1327-1338 ◽  
Author(s):  
Hong Wang ◽  
Aileen X. Wang ◽  
Eugene J. Barrett
Keyword(s):  
Plasma Membrane ◽  
Lipid Rafts ◽  
Actin Filament ◽  
Pi3k Pathway ◽  
Membrane Lipid ◽  
Cortical Actin ◽  
Caveolin 1 ◽  
Actin Microfilament ◽  
Igf I ◽  
Insulin Uptake

Insulin's trans-endothelial transport (TET) is critical for its metabolic action on muscle and involves trafficking of insulin bound to its receptor (or at high insulin concentrations, the IGF-I receptor) via caveolae. However, whether caveolae-mediated insulin TET involves actin cytoskeleton organization is unknown. Here we address whether insulin regulates actin filament organization in bovine aortic endothelial cells (bAEC) and whether this affects insulin uptake and TET. We found that insulin induced extensive cortical actin filament remodeling within 5 min. This remodeling was inhibited not only by disruption of actin microfilament organization but also by inhibition of phosphatidylinositol 3-kinase (PI3K) or by disruption of lipid rafts using respective specific inhibitors. Knockdown of either caveolin-1 or Akt using specific small interfering RNA also eliminated the insulin-induced cortical actin filament remodeling. Blocking either actin microfilament organization or PI3K pathway signaling inhibited both insulin uptake and TET. Disruption of actin microfilament organization also reduced the caveolin-1, insulin receptor, and IGF-I receptor located at the plasma membrane. Exposing bAEC for 6 h to either TNFα or IL-6 blocked insulin-induced cortical actin remodeling. Extended exposure (24 h) also inhibited actin expression at both mRNA and protein levels. We conclude that insulin-induced cortical actin filament remodeling in bAEC is required for insulin's TET in a PI3K/Akt and plasma membrane lipid rafts/caveolae-dependent fashion, and proinflammatory cytokines TNFα and IL-6 block this process.

1P-0227 Apolipoprotein A-1 interaction with plasma membrane lipid rafts controls cholesterol export from macrophages

2003 ◽  
Vol 4 (2) ◽  
pp. 69 ◽  
Author(s):  
W. Jessup ◽  
K. Gaus ◽  
L. Kritharides ◽  
A. Boettcher ◽  
W. Drobnik ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Lipid Rafts ◽  
Membrane Lipid ◽  
Apolipoprotein A ◽  
Plasma Membrane Lipid

scholarly journals Moderate Static Magnetic Field (6 mT)-Induced Lipid Rafts Rearrangement Increases Silver NPs Uptake in Human Lymphocytes

Molecules ◽  
2020 ◽  
Vol 25 (6) ◽  
pp. 1398
Author(s):  
Cristian Vergallo ◽  
Elisa Panzarini ◽  
Bernardetta Anna Tenuzzo ◽  
Stefania Mariano ◽  
Ada Maria Tata ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Lipid Rafts ◽  
Lipid Raft ◽  
Human Lymphocytes ◽  
Peripheral Blood Lymphocytes ◽  
Membrane Lipid ◽  
Membrane Perturbation ◽  
Plasma Membrane Lipid ◽  
Silver Nps ◽  
Surface Ligand

One of the most relevant drawbacks in medicine is the ability of drugs and/or imaging agents to reach cells. Nanotechnology opened new horizons in drug delivery, and silver nanoparticles (AgNPs) represent a promising delivery vehicle for their adjustable size and shape, high-density surface ligand attachment, etc. AgNPs cellular uptake involves different endocytosis mechanisms, including lipid raft-mediated endocytosis. Since static magnetic fields (SMFs) exposure induces plasma membrane perturbation, including the rearrangement of lipid rafts, we investigated whether SMF could increase the amount of AgNPs able to pass the peripheral blood lymphocytes (PBLs) plasma membrane. To this purpose, the effect of 6-mT SMF exposure on the redistribution of two main lipid raft components (i.e., disialoganglioside GD3, cholesterol) and on AgNPs uptake efficiency was investigated. Results showed that 6 mT SMF: (i) induces a time-dependent GD3 and cholesterol redistribution in plasma membrane lipid rafts and modulates gene expression of ATP-binding cassette transporter A1 (ABCA1), (ii) increases reactive oxygen species (ROS) production and lipid peroxidation, (iii) does not induce cell death and (iv) induces lipid rafts rearrangement, that, in turn, favors the uptake of AgNPs. Thus, it derives that SMF exposure could be exploited to enhance the internalization of NPs-loaded therapeutic or diagnostic molecules.

scholarly journals Membrane lipid rafts are disturbed in the response of rat skeletal muscle to short-term disuse

2017 ◽  
Vol 312 (5) ◽  
pp. C627-C637 ◽  
Author(s):  
Alexey M. Petrov ◽  
Violetta V. Kravtsova ◽  
Vladimir V. Matchkov ◽  
Alexander N. Vasiliev ◽  
Andrey L. Zefirov ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Plasma Membrane ◽  
Lipid Rafts ◽  
Lipid Raft ◽  
Motor Nerve ◽  
Membrane Lipid ◽  
Hindlimb Suspension ◽  
Cholera Toxin B Subunit ◽  
Plasma Membrane Lipid ◽  
Intracellular Ca

Marked loss of skeletal muscle mass occurs under various conditions of disuse, but the molecular and cellular mechanisms leading to atrophy are not completely understood. We investigate early molecular events that might play a role in skeletal muscle remodeling during mechanical unloading (disuse). The effects of acute (6–12 h) hindlimb suspension on the soleus muscles from adult rats were examined. The integrity of plasma membrane lipid rafts was tested utilizing cholera toxin B subunit or fluorescent sterols. In addition, resting intracellular Ca2+ level was analyzed. Acute disuse disturbed the plasma membrane lipid-ordered phase throughout the sarcolemma and was more pronounced in junctional membrane regions. Ouabain (1 µM), which specifically inhibits the Na-K-ATPase α2 isozyme in rodent skeletal muscles, produced similar lipid raft changes in control muscles but was ineffective in suspended muscles, which showed an initial loss of α2 Na-K-ATPase activity. Lipid rafts were able to recover with cholesterol supplementation, suggesting that disturbance results from cholesterol loss. Repetitive nerve stimulation also restores lipid rafts, specifically in the junctional sarcolemma region. Disuse locally lowered the resting intracellular Ca2+ concentration only near the neuromuscular junction of muscle fibers. Our results provide evidence to suggest that the ordering of lipid rafts strongly depends on motor nerve input and may involve interactions with the α2 Na-K-ATPase. Lipid raft disturbance, accompanied by intracellular Ca2+ dysregulation, is among the earliest remodeling events induced by skeletal muscle disuse.

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 Analysis of Detergent-Resistant Membranes in Arabidopsis. Evidence for Plasma Membrane Lipid Rafts

2004 ◽  
Vol 137 (1) ◽  
pp. 104-116 ◽  
Author(s):  
Georg H.H. Borner ◽  
D. Janine Sherrier ◽  
Thilo Weimar ◽  
Louise V. Michaelson ◽  
Nathan D. Hawkins ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Lipid Rafts ◽  
Membrane Lipid ◽  
Plasma Membrane Lipid ◽  
Detergent Resistant Membranes

scholarly journals Cell-To-Cell Variability in Plasma Membrane Lipid Rafts

2013 ◽  
Vol 104 (2) ◽  
pp. 191a-192a
Author(s):  
Roland Schwarzer ◽  
Silvia Scolari ◽  
Reismann David ◽  
Rolf Schwarzer ◽  
Andreas Herrmann
Keyword(s):  
Plasma Membrane ◽  
Lipid Rafts ◽  
Membrane Lipid ◽  
Plasma Membrane Lipid ◽  
Cell To Cell Variability

IGF-I induced rapid recruitment of integrin β1 to lipid rafts is Caveolin-1 dependent

2009 ◽  
Vol 380 (3) ◽  
pp. 489-492 ◽  
Author(s):  
B. Salani ◽  
L. Briatore ◽  
P. Contini ◽  
M. Passalacqua ◽  
E. Melloni ◽  
...  
Keyword(s):  
Lipid Rafts ◽  
Integrin Β1 ◽  
Caveolin 1 ◽  
Igf I

scholarly journals Intracellular Retention of Glycosylphosphatidyl Inositol-Linked Proteins in Caveolin-Deficient Cells

2002 ◽  
Vol 22 (11) ◽  
pp. 3905-3926 ◽  
Author(s):  
Federica Sotgia ◽  
Babak Razani ◽  
Gloria Bonuccelli ◽  
William Schubert ◽  
Michela Battista ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Lipid Rafts ◽  
Recombinant Expression ◽  
Surface Expression ◽  
Cell Surface Expression ◽  
Null Mouse ◽  
Tissue Samples ◽  
Caveolin 1 ◽  
Glycosylphosphatidyl Inositol

ABSTRACT The relationship between glycosylphosphatidyl inositol (GPI)-linked proteins and caveolins remains controversial. Here, we derived fibroblasts from Cav-1 null mouse embryos to study the behavior of GPI-linked proteins in the absence of caveolins. These cells lack morphological caveolae, do not express caveolin-1, and show a ∼95% down-regulation in caveolin-2 expression; these cells also do not express caveolin-3, a muscle-specific caveolin family member. As such, these caveolin-deficient cells represent an ideal tool to study the role of caveolins in GPI-linked protein sorting. We show that in Cav-1 null cells GPI-linked proteins are preferentially retained in an intracellular compartment that we identify as the Golgi complex. This intracellular pool of GPI-linked proteins is not degraded and remains associated with intracellular lipid rafts as judged by its Triton insolubility. In contrast, GPI-linked proteins are transported to the plasma membrane in wild-type cells, as expected. Furthermore, recombinant expression of caveolin-1 or caveolin-3, but not caveolin-2, in Cav-1 null cells complements this phenotype and restores the cell surface expression of GPI-linked proteins. This is perhaps surprising, as GPI-linked proteins are confined to the exoplasmic leaflet of the membrane, while caveolins are cytoplasmically oriented membrane proteins. As caveolin-1 normally undergoes palmitoylation on three cysteine residues (133, 143, and 156), we speculated that palmitoylation might mechanistically couple caveolin-1 to GPI-linked proteins. In support of this hypothesis, we show that palmitoylation of caveolin-1 on residues 143 and 156, but not residue 133, is required to restore cell surface expression of GPI-linked proteins in this complementation assay. We also show that another lipid raft-associated protein, c-Src, is retained intracellularly in Cav-1 null cells. Thus, Golgi-associated caveolins and caveola-like vesicles could represent part of the transport machinery that is necessary for efficiently moving lipid rafts and their associated proteins from the trans-Golgi to the plasma membrane. In further support of these findings, GPI-linked proteins were also retained intracellularly in tissue samples derived from Cav-1 null mice (i.e., lung endothelial and renal epithelial cells) and Cav-3 null mice (skeletal muscle fibers).

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