Mapping the interaction site for the tarantula toxin hainantoxin-IV (β-TRTX-Hn2a) in the voltage sensor module of domain II of voltage-gated sodium channels

Cai, Tianfu; Luo, Ji; Meng, Er; Ding, Jiuping; Liang, Songping; Wang, Sheng; Z, Liu

doi:10.1016/j.peptides.2014.09.005

Cited by 36 publications

(62 citation statements)

References 43 publications

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“…This structural feature has been proposed to promote not only GMT-voltage-gated ion channel interactions, but also GMT-lipid membrane interactions [12,13,17,18,48]. Several spider GMTs have been shown to interact with model membranes and the unique structures of these peptides have been proposed to facilitate a tri-molecular interaction involving the GMTs, the lipid membrane and target voltage-gated ion channels [14,47,[50][51][52].…”

Section: Discussionmentioning

confidence: 99%

“…For example, the channel binding region of ProTx-II has been determined to bind to F813, D816 and E818 on hNa V 1.7, whereas HwTx-IV has been shown to interact with E811, L814, D816, E818 on the same channel [15,16]. This raises the possibility that the toxins, rather than recognizing specific channel residues, identify a local binding site on the voltage sensor domain that is structurally and chemically complementary to the surface motif of the GMTs [12,17].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Spider peptide toxin HwTx-IV engineered to bind to lipid membranes has an increased inhibitory potency at human voltage-gated sodium channel hNa V 1.7

Agwa¹,

Lawrence²,

Deplazes³

et al. 2017

Biochimica et Biophysica Acta (BBA) - Biomembranes

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Spider peptide toxin HwTx-IV engineered to bind to lipid membranes has an increased inhibitory potency at human voltage-gated sodium channel hNa V 1.7

Agwa¹,

Lawrence²,

Deplazes³

et al. 2017

Biochimica et Biophysica Acta (BBA) - Biomembranes

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“…11D). As for Tp1a, m-TRTX-Hhn1b and m-TRTX-Hs2a preferentially inhibit Na V 1.2, Na V 1.3, and Na V 1.7, with no effect on Na V 1.4 and Na V 1.5 (Xiao et al, 2008;Cai et al, 2015). Mutations of m-TRTX-Hhn1b revealed that Lys27 and Arg29 are critical for activity on Na V channels (Li et al, 2004), whereas an alanine scan of m-TRTX-Hs2a revealed that residues Lys18, Arg26, Lys32, and Trp30 are critical for Na V channel inhibition (Minassian et al, 2013;Revell et al, 2013).…”

Section: Resultsmentioning

confidence: 86%

Identification and Characterization of ProTx-III [μ-TRTX-Tp1a], a New Voltage-Gated Sodium Channel Inhibitor from Venom of the Tarantula Thrixopelma pruriens

et al. 2015

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Spider venoms are a rich source of ion channel modulators with therapeutic potential. Given the analgesic potential of subtypeselective inhibitors of voltage-gated sodium (Na V ) channels, we screened spider venoms for inhibitors of human Na V 1.7 (hNa V 1.7) using a high-throughput fluorescent assay. Here, we describe the discovery of a novel Na V 1.7 inhibitor, m-TRTX-Tp1a (Tp1a), isolated from the venom of the Peruvian green-velvet tarantula Thrixopelma pruriens. Recombinant and synthetic forms of this 33-residue peptide preferentially inhibited hNa V 1.7 . hNa V 1.6 . hNa V 1.2 . hNa V 1.1 . hNa V 1.3 channels in fluorescent assays. Na V 1.7 inhibition was diminished (IC 50 11.5 nM) and the association rate decreased for the C-terminal acid form of Tp1a compared with the native amidated form (IC 50 2.1 nM), suggesting that the peptide C terminus contributes to its interaction with hNa V 1.7. Tp1a had no effect on human voltage-gated calcium channels or nicotinic acetylcholine receptors at 5 mM. Unlike most spider toxins that modulate Na V channels, Tp1a inhibited hNa V 1.7 without significantly altering the voltage dependence of activation or inactivation. Tp1a proved to be analgesic by reversing spontaneous pain induced in mice by intraplantar injection in OD1, a scorpion toxin that potentiates hNa V 1.7. The structure of Tp1a as determined using NMR spectroscopy revealed a classic inhibitor cystine knot (ICK) motif. The molecular surface of Tp1a presents a hydrophobic patch surrounded by positively charged residues, with subtle differences from other ICK spider toxins that might contribute to its different pharmacological profile. Tp1a may help guide the development of more selective and potent hNa V 1.7 inhibitors for treatment of chronic pain.

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“…Similarly, hainantoxin-IV was found to inhibit TTX-s rat Na V isoforms 231 and was shown to inhibit Na V 1.1, 1.2, and 1.7, while having no effect over Na V 1.4 and 1.5 232 . The efficacy of hainantoxin-IV in other TTX-s rat Na V isoforms, such as Na V 1.3 and Na V 1.6, were not tested.…”

Section: Pme1a Exhibits Agonistic Activity Towards Trpv1 and Induces mentioning

confidence: 95%

“…The efficacy of hainantoxin-IV in other TTX-s rat Na V isoforms, such as Na V 1.3 and Na V 1.6, were not tested. The binding site and the binding surface of hainantoxins is also poorly defined, with some suggesting hainantoxin-I may bind to binding site 1 on Na V channels 233 , while evidence based on kinetics changes following exposure to hainantoxin-IV indicate binding via other sites that regulate inactivation kinetics 232 . More characterisation would need to be conducted regarding hainantoxins before the properties and molecular targets of this family can be defined.…”

Section: Pme1a Exhibits Agonistic Activity Towards Trpv1 and Induces mentioning

confidence: 99%

A pharmacological and transcriptomic approach to exploring novel pain targets

Yin¹

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Ever since the discovery that mutations in the voltage-gated sodium channel 1.7 protein are responsible for human congenital insensitivity to pain, the voltage-gated sodium channel (Na V ) family of ion channels has been the subject of intense research with the hope of discovering novel analgesics. We now know that Na V 1.7 deletion in select neuronal populations yield different phenotypes, with the deletion of Na V 1.7 in all sensory neurons being successful at abolishing mechanical and heat-induced pain. However, it is rapidly becoming apparent that a number of pain syndromes are not modulated by Na V 1.7 at all, such as oxaliplatin-mediated neuropathy. It is particularly interesting to note that the loss of Na V 1.7 function is also associated with the selective inhibition of pain mediated by specific stimuli, such as that observed in burn-induced pain where Na V 1.7 gene knockout abolished thermal allodynia but did not affect mechanical allodynia. Accordingly, significant interests exist in delineating the contribution of other Na V isoforms in modality-specific pain pathways. Two other isoforms, Na V 1.6 and Na V 1.8, are now specifically implicated in some Na V 1.7-independent conditions such as oxaliplatin-induced cold allodynia. Such selective contributions of specific ion channel isoforms to pain highlight the need to discover other putative protein targets involved in mediating nociception.The aim of my work is therefore to discover selective molecular inhibitors of Na V 1.6 and Na V 1.8, to find useful cell models for peripheral nociceptors, to investigate the roles of Na V 1.6 and Na V 1.8 in an animal model of burn-induced pain, and to screen for putative new targets for analgesia in burn-related pain.Chapter 2 of this thesis describes activity-guided discovery of novel Na V 1.6 and Na V 1.8-modulting peptides from crude spider venoms. Crude venom from Poecilotheria metallica successfully reduced Na V 1.8-mediated voltage changes in HEK293-expressing cells. A new Na V 1.8-inhibitory peptide was sequenced from the venom and named Pme1a. However, Pme1a exhibited TRPV1 agonist activity and induced nocifensive behaviours, such as paw licking, after injection into the hind paws of mice, indicating the peptide was not a selective Na V 1.8 modulator and was unsuitable as a tool for Na V 1.8 investigation.iii With the unsuccessful exploration of spider venoms for new specific inhibitors, I then investigated in vitro cell models as tools to research specific nociceptor subtypes that express Na V 1.6 or Na V 1.8. In Chapter 3, I provide the first complete transcriptome of three common in vitro neuronal cell lines (SH-SY5Y, F-11, and ND7/23) to examine whether they were appropriate for investigating the functions of Na V 1.6 and Na V 1.8, and to identify if the cell lines resemble in vivo dorsal root ganglion (DRG) neuronal subclasses. The three cell lines examined all expressed proteins belonging to similar pathways and of similar proportions to native DRG neurons. However, they did not express any ce...

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Mapping the interaction site for the tarantula toxin hainantoxin-IV (β-TRTX-Hn2a) in the voltage sensor module of domain II of voltage-gated sodium channels

Cited by 36 publications

References 43 publications

Spider peptide toxin HwTx-IV engineered to bind to lipid membranes has an increased inhibitory potency at human voltage-gated sodium channel hNa V 1.7

Spider peptide toxin HwTx-IV engineered to bind to lipid membranes has an increased inhibitory potency at human voltage-gated sodium channel hNa V 1.7

Identification and Characterization of ProTx-III [μ-TRTX-Tp1a], a New Voltage-Gated Sodium Channel Inhibitor from Venom of the Tarantula Thrixopelma pruriens

A pharmacological and transcriptomic approach to exploring novel pain targets

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