Cisplatin activates volume sensitive LRRC8 channel mediated currents in <i>Xenopus</i> oocytes

Gradogna, Antonella; Gaitán‐Peñas, Héctor; Boccaccio, Anna; Estévez, Raúl; Pusch, Michael

doi:10.1080/19336950.2017.1284717

Cited by 17 publications

(11 citation statements)

References 22 publications

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“…In addition, it has been shown in mammalian cells that unrelated compounds, such as the antibiotic blasticidin [ 48 ] and cisplatin drugs [ 28 ], can pass through the channel, and the latter is also able to activate the channel [ 28 ]. A similar behavior has been observed in oocytes, in which intracellular cisplatin accumulation strongly activates the channel [ 49 ]. The mechanism of this activation is unknown, but we speculate that intracellular cisplatin (but not blasticidin) may activate the signal transduction cascades that activate LRRC8 proteins.…”

Section: Further Characteristics Of the Functional Properties Of Tsupporting

confidence: 76%

Expression of LRRC8/VRAC Currents in Xenopus Oocytes: Advantages and Caveats

Gaitán‐Peñas

Pusch

Estévez

2018

IJMS

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Volume-regulated anion channels (VRACs) play a role in controlling cell volume by opening upon cell swelling. Apart from controlling cell volume, their function is important in many other physiological processes, such as transport of metabolites or drugs, and extracellular signal transduction. VRACs are formed by heteromers of the pannexin homologous protein LRRC8A (also named Swell1) with other LRRC8 members (B, C, D, and E). LRRC8 proteins are difficult to study, since they are expressed in all cells of our body, and the channel stoichiometry can be changed by overexpression, resulting in non-functional heteromers. Two different strategies have been developed to overcome this issue: complementation by transient transfection of LRRC8 genome-edited cell lines, and reconstitution in lipid bilayers. Alternatively, we have used Xenopus oocytes as a simple system to study LRRC8 proteins. Here, we have reviewed all previous experiments that have been performed with VRAC and LRRC8 proteins in Xenopus oocytes. We also discuss future strategies that may be used to perform structure-function analysis of the VRAC in oocytes and other systems, in order to understand its role in controlling multiple physiological functions.

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Section: Further Characteristics Of the Functional Properties Of Tsupporting

confidence: 76%

Expression of LRRC8/VRAC Currents in Xenopus Oocytes: Advantages and Caveats

Gaitán‐Peñas

Pusch

Estévez

2018

IJMS

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“…11g). Due to the described movements, the three l-domains, which approach each other at the threefold axis of symmetry in the apo protein, have retracted by 16 Å to open a gap at the intracellular side (Fig. 6b, Supplementary Video 1).…”

Section: Resultsmentioning

confidence: 99%

“…Although the exact composition of LRRC8 heteromers is currently unknown, they are believed to constitute a diverse family of ion channels whose subunit stoichiometry determines permeation and activation properties [12][13][14] . While the range of permeable substrates of channels containing the C-subunit is restricted to small anions, channels containing the D-or E-subunits also conduct larger molecules including osmolytes, amino acids, and anti-cancer drugs 12,[15][16][17] .…”

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confidence: 99%

Allosteric modulation of LRRC8 channels by targeting their cytoplasmic domains

et al. 2021

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Members of the LRRC8 family form heteromeric assemblies, which function as volume-regulated anion channels. These modular proteins consist of a transmembrane pore and cytoplasmic leucine-rich repeat (LRR) domains. Despite their known molecular architecture, the mechanism of activation and the role of the LRR domains in this process has remained elusive. Here we address this question by generating synthetic nanobodies, termed sybodies, which target the LRR domain of the obligatory subunit LRRC8A. We use these binders to investigate their interaction with homomeric LRRC8A channels by cryo-electron microscopy and the consequent effect on channel activation by electrophysiology. The five identified sybodies either inhibit or enhance activity by binding to distinct epitopes of the LRR domain, thereby altering channel conformations. In combination, our work provides a set of specific modulators of LRRC8 proteins and reveals the role of their cytoplasmic domains as regulators of channel activity by allosteric mechanisms.

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“…Further limiting factors are likely involved because the overexpression of functional LRRC8 heteromers did not increase swelling-induced chloride currents above wild-type levels ( 4 ), and different cells with similar LRRC8 expression levels showed differences in VRAC activity ( 73 ). In addition, VRACs can be activated under isovolumetric conditions, e.g., by cisplatin or sphingosine-1-phosphate ( 13 , 44 , 74 ), likely by mechanisms not involving changes in ionic strength. It will be exciting to see whether post-translational modifications or binding partners of LRRC8 proteins play a role.…”

Section: Main Textmentioning

confidence: 99%

Biophysics and Structure-Function Relationships of LRRC8-Formed Volume-Regulated Anion Channels

König

Stauber

2019

Biophysical Journal

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Volume-regulated anion channels (VRACs) are key players in regulatory volume decrease of vertebrate cells by mediating the extrusion of chloride and organic osmolytes. They play additional roles in various physiological processes beyond their role in osmotic volume regulation. VRACs are formed by heteromers of LRRC8 proteins; LRRC8A (also called SWELL1) is an essential subunit that combines with any of its paralogs, LRRC8B–E, to form hexameric VRAC complexes. The subunit composition of VRACs determines electrophysiological characteristics of their anion transport such as single-channel conductance, outward rectification, and depolarization-dependent inactivation kinetics. In addition, differently composed VRACs conduct diverse substrates, such as LRRC8D enhancing VRAC permeability to organic substances like taurine or cisplatin. Here, after a recapitulation of the biophysical properties of VRAC-mediated ion and osmolyte transport, we summarize the insights gathered since the molecular identification of VRACs. We describe the recently solved structures of LRRC8 complexes and discuss them in terms of their structure-function relationships. These studies open up many potential avenues for future research.

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Cisplatin activates volume sensitive LRRC8 channel mediated currents in Xenopus oocytes

Cited by 17 publications

References 22 publications

Expression of LRRC8/VRAC Currents in Xenopus Oocytes: Advantages and Caveats

Expression of LRRC8/VRAC Currents in Xenopus Oocytes: Advantages and Caveats

Allosteric modulation of LRRC8 channels by targeting their cytoplasmic domains

Biophysics and Structure-Function Relationships of LRRC8-Formed Volume-Regulated Anion Channels

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