Single Expressed Glycine Receptor Domains Reconstitute Functional Ion Channels without Subunit-specific Desensitization Behavior

Meiselbach, Heike; Vogel, N. de; Langlhofer, Georg; Stangl, Sabine; Schleyer, Barbara; Bahnassawy, Lamia'a; Sticht, Heinrich; Breitinger, Hans‐Georg; Becker, Cord‐Michael; Villmann, Carmen

doi:10.1074/jbc.m114.559138

Cited by 8 publications

(10 citation statements)

References 42 publications

(51 reference statements)

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“…In a recent study, we could show in chimera between GlyR␣1 and ␣3 that desensitization properties can be transferred between subunits by domain transplantation [12]. These results argue that (i) ion channel properties are transferable between subunits and (ii) domain swapping is a powerful tool to analyze subdomain importance.…”

Section: Discussionmentioning

confidence: 96%

“…Besides the large ICD, amino acid substitutions in the other intracellular TM1-2 loop identified in human patients suffering from the neuromotor disorder hyperekplexia have also been shown to drastically change desensitization properties of GlyR␣1 [20]. In the GlyR␣3 subunit, desensitization is influenced by the presence of a 15 amino acid insert in the TM3-4 loop resulting form alternative splicing events [12]. The fraction of desensitizing currents obtained for GlyR␣1 wt was small compared to the variant that lacks the ICD except both basic stretches at both ends.…”

Section: Discussionmentioning

confidence: 97%

“…Domain swapping between various types of ion channels has been successfully reported without disturbances of ion channel function [12,13]. Although X-ray analysis provided lots of information on the ECD structure of CLRs, the overall fold of the intracellular domain is not yet solved.…”

Section: Discussionmentioning

confidence: 99%

“…Domain exchange without loss of function between CLRs has been successfully demonstrated [9,12]. Here, we analyzed the role of basic stretches (bm) within the ICD for desensitization of GlyR␣1 and the importance of loop length for receptor function by an exchange with the ICD of GLIC (Fig.…”

Section: Glyr Mutants and Glyr-glic Chimerasmentioning

confidence: 98%

See 3 more Smart Citations

Length of the TM3-4 loop of the glycine receptor modulates receptor desensitization

Langlhofer

Janzen

Meiselbach

et al. 2015

Neuroscience Letters

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Section: Discussionmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

Section: Glyr Mutants and Glyr-glic Chimerasmentioning

confidence: 98%

See 2 more Smart Citations

Length of the TM3-4 loop of the glycine receptor modulates receptor desensitization

Langlhofer

Janzen

Meiselbach

et al. 2015

Neuroscience Letters

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“…; Meiselbach et al . ). In contrast to domain swapping experiments, protein truncations often result in non‐functionality.…”

Section: Discussionmentioning

confidence: 97%

The role of charged residues in independent glycine receptor folding domains for intermolecular interactions and ion channel function

Langlhofer

Villmann

2017

Journal of Neurochemistry

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Glycine receptor (GlyR) truncations in the intracellular TM3-4 loop, documented in patients suffering from hyperekplexia and in the mouse mutant oscillator, lead to non-functionality of GlyRs. The missing part that contains the TM3-4 loop, TM4 and C-terminal sequences is essential for pentameric receptor arrangements. In vitro co-expressions of GlyRα1-truncated N-domains and C-domains were able to restore ion channel function. An ionic interaction between both domains was hypothesized as the underlying mechanism. Here, we analysed the proposed ionic interaction between GlyR N- and C-domains using C-terminal constructs with either positively or negatively charged N-termini. Charged residues at the N-terminus of the C-domain did interfere with receptor surface expression and ion channel function. In particular, presence of negatively charged residues at the N-terminus led to significantly decreased ion channel function. Presence of positive charges resulted in reduced maximal currents possibly as a result of repulsion of both domains. If the C-domain was tagged by a myc-epitope, low maximal current amplitudes were detected. Intrinsic charges of the myc-epitope and charged N-terminal ends of the C-domain most probably induce intramolecular interactions. These interactions might hinder the close proximity of C-domains and N-domains, which is a prerequisite for functional ion channel configurations. The remaining basic subdomains close to TM3 and 4 were sufficient for domain complementation and functional ion channel formation. Thus, these basic subdomains forming α-helical elements or an intracellular portal represent attractants for incoming negatively charged chloride ions and interact with the phospholipids thereby stabilizing the GlyR in a conformation that allows ion channel opening.

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Signalling assemblies: the odds of symmetry

Maksay

Marsh

2017

Biochemical Society Transactions

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The assembly of proteins into complexes is fundamental to nearly all biological signalling processes. Symmetry is a dominant feature of the structures of experimentally determined protein complexes, observed in the vast majority of homomers and many heteromers. However, some asymmetric structures exist, and asymmetry also often forms transiently, intractable to traditional structure determination methods. Here, we explore the role of protein complex symmetry and asymmetry in cellular signalling, focusing on receptors, transcription factors and transmembrane channels, among other signalling assemblies. We highlight a recurrent tendency for asymmetry to be crucial for signalling function, often being associated with activated states. We conclude with a discussion of how consideration of protein complex symmetry and asymmetry has significant potential implications and applications for pharmacology and human disease.

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Single Expressed Glycine Receptor Domains Reconstitute Functional Ion Channels without Subunit-specific Desensitization Behavior

Cited by 8 publications

References 42 publications

Length of the TM3-4 loop of the glycine receptor modulates receptor desensitization

Length of the TM3-4 loop of the glycine receptor modulates receptor desensitization

The role of charged residues in independent glycine receptor folding domains for intermolecular interactions and ion channel function

Signalling assemblies: the odds of symmetry

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