Large Intracellular Domain-Dependent Effects of Positive Allosteric Modulators on Glycine Receptors

Lara, César O.; Burgos, Carlos F.; Silva-Grecchi, Tiare; Muñoz-Montesino, Carola; Aguayo, Luis G.; Fuentealba, Jorge; Castro, Patricio; Guzmán, Leonardo; Corringer, Pierre‐Jean; Yévenes, Gonzalo E.; Moraga-Cid, Gustavo

doi:10.1021/acschemneuro.9b00050

Cited by 13 publications

(19 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A change in the volume and polarity of these cavities implicates a role in state-dependent effects of the modulators on channel function 52,53 . Also of note, is the role of the ICD in imparting sensitivity to allosteric ligands in GlyR modulation 54 .…”

Section: The M4 Conformation and The Effect On Intra-subunit And Intementioning

confidence: 99%

Mechanisms of activation and desensitization of full-length glycine receptor in membranes

Kumar

Basak

Rao

et al. 2019

Preprint

View full text Add to dashboard Cite

Glycinergic synapses play a central role in motor control and pain processing in the central nervous system. Glycine receptors (GlyR) are key players in mediating fast inhibitory neurotransmission at these synapses. While previous high-resolution structural studies have provided insights into the molecular architecture of GlyR, several mechanistic questions pertaining to channel function are still unknown. Here, we present Cryo-EM structures of the full-length GlyR protein reconstituted into lipid nanodiscs that are captured in the unliganded (closed) and glycine-bound (open and desensitized) conformations. A comparison of the three states reveals global conformational changes underlying GlyR channel gating. The functional state assignments were validated by molecular dynamics simulations of the structures incorporated in a lipid bilayer. Observed permeation events are in agreement with the anion selectivity of the channel and the reported single-channel conductance of GlyR. These studies establish the structural basis for gating, selectivity, and single-channel conductance of GlyR in a physiological environment.

show abstract

Section: The M4 Conformation and The Effect On Intra-subunit And Intementioning

confidence: 99%

Mechanisms of activation and desensitization of full-length glycine receptor in membranes

Kumar

Basak

Rao

et al. 2019

Preprint

View full text Add to dashboard Cite

show abstract

“…Using computational electrophysiology on a reduced molecular system composed of the trans-membrane domain only in a lipid bilayer and harmonic restraints on the heavy atoms (Figure 1), we have analyzed the ion conductance and selectivity of D&B-open and compared with single-channel electrophysiology; see SI for a justification of the setup. The numerical results collected at a transmembrane potential of 150 mV or 250 mV , which was introduced via a constant electric field (Roux, 2008; Gumbart et al, 2012) or charge imbalance (Sachs et al, 2004; Kutzner et al, 2011) (Figure S1 and SI), indicate that the conductance of D&B-open ranges from 382 ps to 480 ps , which is about five-fold higher than the experimental value of 86 pS (Bormann et al, 1993; Moorhouse et al, 2002; Moroni et al, 2011a; Scott et al, 2015; Lara et al, 2019); see Table S1. Moreover, in-silico permeation assays using a series of polyatomic anions, which were originally used to probe the size of the GlyR ion pore at physiological conditions (Bormann et al, 1987; Rundstrom et al, 1994; Lee et al, 2003), indicate that D&B-open is not only too conductive but also non-selective to the size of the anion, in clear contradiction with the experiments; see Table S2.…”

Section: Figurementioning

confidence: 80%

“…Fourth, both modeling (Cerdan et al, 2018) and structural biology (Yu et al, 2019) consistently indicate that the GlyR conductance at physiological conditions, i.e. 18 88 pS (Bormann et al, 1993; Moorhouse et al, 2002; Moroni et al, 2011a; Scott et al, 2015; Lara et al, 2019), does not require the permeation of fully hydrated chloride ions (i.e. 3.2 Å in radius).…”

Section: Figurementioning

confidence: 92%

On the functional annotation of open-channel structures in the glycine receptor

Cerdan

Cecchini

2020

Preprint

View full text Add to dashboard Cite

The glycine receptor (GlyR) is by far the best-characterized pentameric ligand-gated ion channel with several high-resolution structures from X-ray crystallography, cryo-EM and modeling. Nonetheless, the significance of the currently available openpore conformations is debated due to their diversity in the pore geometry. Here, we discuss the physiological significance of existing models of the GlyR active state based on conductance and selectivity measurements by computational electrophysiology. The results support the conclusion that the original cryo-EM reconstruction of the active state obtained in detergents as well as its subsequent refinement by Molecular Dynamics simulations are likely to be nonphysiological as they feature artificially dilated ion pores. In addition, the calculations indicate that a physiologically relevant open pore configuration should be constricted within a radius of 2.5 and 2.8Å, which is consistent with previous modeling, electrophysiology measurements, and the most recent cryo-EM structures obtained in a native lipid-membrane environment.

show abstract

“…HEK 293 cells (CRL-1573; American Type Culture Collection, Manassas, VA, USA) were cultured using standard methods ( Lara et al., 2019 ). The cells were transfected using XfectTM Transfection Reagent (Clontech, USA) using 1.0 μg of cDNA plasmid encoding the rat GlyR α 3 subunit.…”

Section: Methodsmentioning

confidence: 99%

Inhibition of the Glycine Receptor alpha 3 Function by Colchicine

et al. 2020

Self Cite

View full text Add to dashboard Cite

Colchicine is a plant alkaloid that is widely used as a therapeutic agent. It is widely accepted that colchicine reduces the production of inflammatory mediators mainly by altering cytoskeleton dynamics due to its microtubule polymerization inhibitory activity. However, other lines of evidence have shown that colchicine exerts direct actions on the function of ion channels, which are independent of cytoskeleton alterations. Colchicine is able to modify the function of several pentameric ligand-gated ion channels, including glycine receptors (GlyRs). Previous electrophysiological studies have shown that colchicine act as an antagonist of GlyRs composed by the α 1 subunit. In addition, it was recently demonstrated that colchicine directly bind to the α 3 subunit of GlyRs. Interestingly, other studies have shown a main role of α 3 GlyRs on chronic inflammatory pain. Nevertheless, the functional effects of colchicine on the α 3 GlyR function are still unknown. Here, by using electrophysiological techniques and bioinformatics, we show that colchicine inhibited the function of the α 3 GlyRs. Colchicine elicited concentration-dependent inhibitory effects on α 3 GlyRs at micromolar range and decreased the apparent affinity for glycine. Single-channel recordings show that the colchicine inhibition is associated with a decrease in the open probability of the ion channel. Molecular docking assays suggest that colchicine preferentially bind to the orthosteric site in the closed state of the ion channel. Altogether, our results suggest that colchicine is a competitive antagonist of the α 3 GlyRs.

show abstract

Large Intracellular Domain-Dependent Effects of Positive Allosteric Modulators on Glycine Receptors

Cited by 13 publications

References 48 publications

Mechanisms of activation and desensitization of full-length glycine receptor in membranes

Mechanisms of activation and desensitization of full-length glycine receptor in membranes

On the functional annotation of open-channel structures in the glycine receptor

Inhibition of the Glycine Receptor alpha 3 Function by Colchicine

Contact Info

Product

Resources

About