scholarly journals Formation of artificial lipid bilayers using droplet dielectrophoresis

Lab on a Chip ◽  
2008 ◽  
Vol 8 (10) ◽  
pp. 1617 ◽  
Author(s):  
Sara Aghdaei ◽  
Mairi E. Sandison ◽  
Michele Zagnoni ◽  
Nicolas G. Green ◽  
Hywel Morgan
Keyword(s):  
Lipid Bilayers ◽  
Artificial Lipid Bilayers

scholarly journals A synergy between mechanosensitive calcium- and membrane-binding mediates tension-sensing by C2-like domains

2021 ◽  
Vol 119 (1) ◽  
pp. e2112390119
Author(s):  
Zhouyang Shen ◽  
Kalina T. Belcheva ◽  
Mark Jelcic ◽  
King Lam Hui ◽  
Anushka Katikaneni ◽  
...  
Keyword(s):  
Lipid Bilayers ◽  
Membrane Insertion ◽  
C2 Domain ◽  
Hydrophobic Membrane ◽  
Membrane Recruitment ◽  
Calcium Dependent ◽  
Nuclear Membranes ◽  
Cytosolic Phospholipase ◽  
Artificial Lipid Bilayers ◽  
Quantitative Basis

When nuclear membranes are stretched, the peripheral membrane enzyme cytosolic phospholipase A2 (cPLA2) binds via its calcium-dependent C2 domain (cPLA2-C2) and initiates bioactive lipid signaling and tissue inflammation. More than 150 C2-like domains are encoded in vertebrate genomes. How many of them are mechanosensors and quantitative relationships between tension and membrane recruitment remain unexplored, leaving a knowledge gap in the mechanotransduction field. In this study, we imaged the mechanosensitive adsorption of cPLA2 and its C2 domain to nuclear membranes and artificial lipid bilayers, comparing it to related C2-like motifs. Stretch increased the Ca2+ sensitivity of all tested domains, promoting half-maximal binding of cPLA2 at cytoplasmic resting-Ca2+ concentrations. cPLA2-C2 bound up to 50 times tighter to stretched than to unstretched membranes. Our data suggest that a synergy of mechanosensitive Ca2+ interactions and deep, hydrophobic membrane insertion enables cPLA2-C2 to detect stretched membranes with antibody-like affinity, providing a quantitative basis for understanding mechanotransduction by C2-like domains.

Functional reconstitution of receptors in artificial lipid bilayers

1987 ◽  
Vol 81 (1-2) ◽  
pp. 133-138 ◽  
Author(s):  
Vitaly Vodyanoy ◽  
Dominique Muller ◽  
Kathryn Kramer ◽  
Gary Lynch ◽  
Michel Baudry
Keyword(s):  
Lipid Bilayers ◽  
Artificial Lipid Bilayers

Comparison of large-conductance Ca(2+)-activated K+ channels in artificial bilayer and patch-clamp experiments

1994 ◽  
Vol 266 (3) ◽  
pp. C601-C610 ◽  
Author(s):  
C. L. Kapicka ◽  
A. Carl ◽  
M. L. Hall ◽  
A. L. Percival ◽  
B. W. Frey ◽  
...  
Keyword(s):  
Lipid Bilayers ◽  
Apparent Distance ◽  
Bk Channels ◽  
Open Probability ◽  
K Channels ◽  
Artificial Lipid Bilayers ◽  
Excised Patches ◽  
Lipid Environment ◽  
Artificial Bilayers ◽  
Channel Properties

We compared the gating, ion conduction, and pharmacology of large-conductance Ca(2+)-activated K+ channels (BK channels) from canine colon in artificial lipid bilayers and in excised patches. Both protocols identified 270-pS K(+)-selective channels activated by depolarization and Ca2+ (approximately 130-mV shift of half-activation voltage per 10-fold change in Ca2+) that were inhibited by extracellular tetraethylammonium (TEA) and charybdotoxin. These similarities suggest that the same BK channels are studied in the two techniques. However, we found three quantitative differences between channels in artificial bilayers and patches. 1) Channels in artificial bilayers required fivefold higher free Ca2+ or 80-mV stronger depolarization for activation. 2) The voltage dependence of TEA block was smaller for channels in artificial bilayers. The apparent distance across the membrane field for the TEA binding site was 0.031 for channels in artificial bilayers and 0.23 for channels in patches. 3) ATP (2 mM) decreased open probability (Po) of channels in artificial bilayers, whereas channels in patches were unaffected. Neither GTP nor UTP reduced Po of channels in artificial bilayers. It is possible that these differences may be due to a lack of molecular identity between the channels studied in the two protocols. Alternatively, they may be attributed to alterations in channel properties during reconstitution or to influences of the artificial lipid environment.

scholarly journals Single channel properties of lysenin measured in artificial lipid bilayers and their applications to biomolecule detection

2010 ◽  
Vol 86 (9) ◽  
pp. 920-925 ◽  
Author(s):  
Takaaki AOKI ◽  
Minako HIRANO ◽  
Yuko TAKEUCHI ◽  
Toshihide KOBAYASHI ◽  
Toshio YANAGIDA ◽  
...  
Keyword(s):  
Lipid Bilayers ◽  
Single Channel ◽  
Biomolecule Detection ◽  
Artificial Lipid Bilayers ◽  
Channel Properties

scholarly journals Membrane Crowding and Anomalous Diffusion in Artificial Lipid Bilayers

2016 ◽  
Vol 110 (3) ◽  
pp. 568a ◽  
Author(s):  
Helena L.E. Coker ◽  
Matthew R. Cheetham ◽  
Ravinash Krishna Kumar ◽  
Mark I. Wallace
Keyword(s):  
Lipid Bilayers ◽  
Anomalous Diffusion ◽  
Artificial Lipid Bilayers

scholarly journals Channel Formation by CarO, the Carbapenem Resistance-Associated Outer Membrane Protein of Acinetobacter baumannii

2005 ◽  
Vol 49 (12) ◽  
pp. 4876-4883 ◽  
Author(s):  
Axel Siroy ◽  
Virginie Molle ◽  
Christelle Lemaître-Guillier ◽  
David Vallenet ◽  
Martine Pestel-Caron ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Acinetobacter Baumannii ◽  
Outer Membrane ◽  
Lipid Bilayers ◽  
Outer Membrane Protein ◽  
Carbapenem Resistance ◽  
Protein Band ◽  
Multidrug Resistant ◽  
Channel Formation ◽  
Artificial Lipid Bilayers

ABSTRACT It has been recently shown that resistance to both imipenem and meropenem in multidrug-resistant clinical strains of Acinetobacter baumannii is associated with the loss of a heat-modifiable 25/29-kDa outer membrane protein, called CarO. This study aimed to investigate the channel-forming properties of CarO. Mass spectrometry analyses of this protein band detected another 25-kDa protein (called Omp25), together with CarO. Both proteins presented similar physicochemical parameters (M w and pI). We overproduced and purified the two polypeptides as His-tagged recombinant proteins. Circular dichroism analyses demonstrated that the secondary structure of these proteins was mainly a β-strand conformation with spectra typical of porins. We studied the channel-forming properties of proteins by reconstitution into artificial lipid bilayers. In these conditions, CarO induced ion channels with a conductance value of 110 pS in 1 M KCl, whereas the Omp25 protein did not form any channels, despite its suggested porin function. The pores formed by CarO showed a slight cationic selectivity and no voltage closure. No specific imipenem binding site was found in CarO, and this protein would rather form unspecific monomeric channels.

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