Green Fluorescent Protein Changes the Conductance of Connexin 43 (Cx43) Hemichannels Reconstituted in Planar Lipid Bilayers

Carnarius, Christian; Kreir, Mohamed; Krick, Marcel; Methfessel, Christoph; Moehrle, Volker; Valerius, Oliver; Brüggemann, Andrea; Steinem, Claudia; Fertig, Niels

doi:10.1074/jbc.m111.319871

Cited by 16 publications

(12 citation statements)

References 58 publications

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“…In this context, Thompson recorded pannexin-1 hemichannel activity and observed at least two distinct conductance levels (Thompson et al 2006). Similarly, high subconductance stages have been observed in connexin 43 hemichannel (Contreras et al 2003;Carnarius et al 2012) and maxi anion (Schwarze and Kolb 1984;Olesen and Bundgaard 1992;Dutta et al 2004;Akanda et al 2008) opening. Additionally, a few number of papers studied the electrophysiological properties in these pore-forming proteins and used fluorescent dyes in these studies.…”

Section: Fluorescent Dyes Used To Observe Channels Permeable To Largementioning

confidence: 89%

Fluorescent dyes as a reliable tool in P2X7 receptor-associated pore studies

Ferreira

Pereira

Faria

2015

J Bioenerg Biomembr

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Since the nineteenth century, a great amount of different biological structures and processes have been assessed by fluorescent dyes. Along with the uses of these compounds as vital and histological dyes, some fluorescent dyes have become valuable tools for the study of the pore phenomenon in plasma membranes. Some ion channels capable of forming large conductance channels, such as P2X7, TRPV1, VDAC-1 and the maxi-anion channels transiently alter the plasma membrane permeability, producing pores, which permit the passage of molecules of up to 1,000 Da. In this review, we discuss the uses of the fluorescent dyes chosen in diverse studies of this topic up to now.

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Section: Fluorescent Dyes Used To Observe Channels Permeable To Largementioning

confidence: 89%

Fluorescent dyes as a reliable tool in P2X7 receptor-associated pore studies

Ferreira

Pereira

Faria

2015

J Bioenerg Biomembr

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“…Two direct demonstrations that connexins form functional membrane units have been the reconstitution of hemichannels in lipid bilayers and identification of the unitary conductance in voltage clamp recordings. In liposomes or planar lipid bilayers, the sensitivity to inhibitors like heptanol, carbenoxolone and lanthanum ions (La 3+ ), and permeability properties to small molecules and Ca 2+ has been demonstrated [18–25], indicating that connexin hemichannels could operate without the necessity of accessory proteins and without involvement of other protein forming channels. A possible bias of the electrophysiological characterization of the biophysical hemichannel properties is that accessory proteins, phosphorylation state, ionic concentrations and nature of the permeating charge carriers may all influence the recorded parameters.…”

Section: The Early Beginnings and Maturation Of The Concept Of Functimentioning

confidence: 99%

Hunting for connexin hemichannels

2014

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a b s t r a c tConnexin hemichannels (connexons) are building blocks of gap junctions but also function as free unapposed channels, which has become an active field of research. Defining functions of hemichannels and their involvement in any biological event requires ruling out possible participation of other channels that share biophysical and regulatory properties, for example pannexins, CALHM1 and P2X receptors. The lack of specific inhibitors for these channels has become an obstacle in elucidating the role of connexin hemichannels. Several experimental approaches are now available to identify hemichannels at the cell surface and to characterize their electrophysiological, permeability and regulatory properties. The use of connexin knockout/knockdown, and the development of peptides that target intracellular connexin domains and specific antibodies directed to extracellular domains have helped to dissect the role of hemichannels in endogenously expressing systems. Moreover, studies of connexin mutants in exogenous expression systems have provided convincing evidence on hemichannels in the pathogenesis of several human genetic diseases. We here present a brief overview of connexin hemichannels as functional channels and itemize a list of aspects to consider when concluding on their involvement.

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“…A remarkable protein expression in a liposomal system was reported by Murtas et al [34] who used a well‐defined, cell‐free minimal protein synthesis set, composed of 36 enzymes, 70S ribosomes, tRNAs, and cofactors (Pure Systems), which was co‐encapsulated with a plasmid, coding for enhanced GFP (eGFP). Furthermore, an controllable membrane permeability [38] and more efficient nutrient uptake have been investigated by co‐expression of a pore‐forming protein in the liposomal membrane. As a result eGFP expression inside the vesicle could be continued for up to several days since energy and nutrients could be transported from the outside into the vesicular compartment [39–41].…”

Section: Evolving Fields To Be “Under the Umbrella” Of Synthetic Biologymentioning

confidence: 99%