Structural Insights into the Atomistic Mechanisms of Action of Small Molecule Inhibitors Targeting the KCa3.1 Channel Pore

Nguyen, Hai M.; Singh, Vikrant; Pressly, Brandon; Jenkins, David P.; Wulff, Heike; Yarov‐Yarovoy, Vladimir

doi:10.1124/mol.116.108068

Cited by 42 publications

(42 citation statements)

References 81 publications

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“…The senicapoc moiety (in the upper part) is binding in a similar region as described for a rosetta homology model of K Ca 3.1 channel. In this model senicapoc binds also to the upper inner pore of the channel . The dye is lying outside of the inner pore (lower part) directly on the surface.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Small‐Molecule Fluorescent Probes for the In Vitro Imaging of Calcium‐Activated Potassium Channel K_Ca3.1

et al. 2020

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Small‐molecule probes for the in vitro imaging of KCa3.1 channel‐expressing cells were developed. Senicapoc, showing high affinity and selectivity for the KCa3.1 channels, was chosen as the targeting component. BODIPY dyes 15–20 were synthesized and connected by a CuI‐catalyzed azide–alkyne [3+2]cycloaddition with propargyl ether senicapoc derivative 8, yielding fluorescently labeled ligands 21–26. The dimethylpyrrole‐based imaging probes 25 and 26 allow staining of KCa3.1 channels in NSCLC cells. The specificity was shown by removing the punctate staining pattern by pre‐incubation with senicapoc. The density of KCa3.1 channels detected with 25 and by immunostaining was identical. The punctate structure of the labeled channels could also be observed in living cells. Molecular modeling showed binding of the senicapoc‐targeting component towards the binding site within the ion channel and orientation of the linker with the dye along the inner surface of the ion channel.

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Section: Resultsmentioning

confidence: 99%

Synthesis of Small‐Molecule Fluorescent Probes for the In Vitro Imaging of Calcium‐Activated Potassium Channel K_Ca3.1

et al. 2020

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“…In this model senicapoc binds also to the upper inner pore of the channel. [19] Thedye is lying outside of the inner pore (lower part) directly on the surface.Therefore, the linker shows as uitable length to connect both moieties through the inner pore. ( Figure 6D)T he distance between both O-atoms is circa 7.86 .T his analysis confirms asimilar binding mode of the fluorescently labeled probe 25 and senicapoc in the inner pore of the K Ca 3.1 channel.…”

Section: Methodsmentioning

confidence: 99%

Synthesis of Small‐Molecule Fluorescent Probes for the In Vitro Imaging of Calcium‐Activated Potassium Channel K_Ca3.1

et al. 2020

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Small-molecule probes for the in vitro imaging of K Ca 3.1 channel-expressing cells were developed. Senicapoc, showing high affinity and selectivity for the K Ca 3.1 channels, was chosen as the targeting component. BODIPY dyes 15-20 were synthesized and connected by aC u I -catalyzed azidealkyne [3+ +2]cycloaddition with propargyl ether senicapoc derivative 8,yielding fluorescently labeled ligands 21-26.The dimethylpyrrole-based imaging probes 25 and 26 allow staining of K Ca 3.1 channels in NSCLC cells.T he specificity was shown by removing the punctate staining pattern by preincubation with senicapoc.T he density of K Ca 3.1 channels detected with 25 and by immunostaining was identical. The punctate structure of the labeled channels could also be observed in living cells.M olecular modeling showed binding of the senicapoc-targeting component towards the binding site within the ion channel and orientation of the linker with the dye along the inner surface of the ion channel.Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

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“…TRAM-34 is an IK Ca K 1 channel blocker that specifically blocks K Ca 3.1 by occupying the site that K 1 binds to before entering the selectivity filter (Nguyen et al, 2017). TRAM-34 produced the most robust inhibition of OT-mediated changes in membrane potential.…”

Section: Resultsmentioning

confidence: 99%

“…Paxilline is a selective inhibitor of the BK Ca channel (Sanchez and McManus, 1996), whereas charybdotoxin is an inhibitor of various IK Ca (Anderson et al, 1988;Ishii et al, 1997) and BK Ca (Qiu et al, 2009) channels. TRAM-34 is a selective inhibitor of IK Ca channel K Ca 3.1, which has been shown to reach maximum blockade in 3-6 minutes (Nguyen et al, 2017;Staal et al, 2017). In COS-7 cells, 100 nM TRAM-34 blocked ∼90% of IK Ca currents (Wulff et al, 2000).…”

Section: Methodsmentioning

confidence: 99%

A Comparison of the Ability of Leu⁸- and Pro⁸-Oxytocin to Regulate Intracellular Ca²⁺and Ca²⁺-Activated K⁺Channels at Human and Marmoset Oxytocin Receptors

Pierce¹,

Mehrotra²,

Mustoe³

et al. 2019

Mol Pharmacol

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The neurohypophyseal hormone oxytocin (OT) regulates biologic functions in both peripheral tissues and the central nervous system. In the central nervous system, OT influences social processes, including peer relationships, maternal-infant bonding, and affiliative social relationships. In mammals, the nonapeptide OT structure is highly conserved with leucine in the eighth position (Leu 8 -OT). In marmosets (Callithrix), a nonsynonymous nucleotide substitution in the OXT gene codes for proline in the eighth residue position (Pro 8 -OT). OT binds to its cognate G protein-coupled receptor (OTR) and exerts diverse effects, including stimulation (G s ) or inhibition (G i/o ) of adenylyl cyclase, stimulation of potassium channel currents (G i ), and activation of phospholipase C (G q ). Chinese hamster ovary cells expressing marmoset or human oxytocin receptors (mOTRs or hOTRs, respectively) were used to characterize OT signaling. At the mOTR, Pro 8 -OT was more efficacious than Leu 8 -OT in measures of G q activation, with both peptides displaying subnanomolar potencies. At the hOTR, neither the potency nor efficacy of Pro 8 -OT and Leu 8 -OT differed with respect to G q signaling. In both mOTR-and hOTR-expressing cells, Leu 8 -OT was more potent and modestly more efficacious than Pro 8 -OT in inducing hyperpolarization. In mOTR cells, Leu 8 -OT-induced hyperpolarization was modestly inhibited by pretreatment with pertussis toxin (PTX), consistent with a minor role for G i/o activation; however, the Pro 8 -OT response in mOTR and hOTR cells was PTX insensitive. These findings are consistent with membrane hyperpolarization being largely mediated by a G q signaling mechanism leading to Ca 21 -dependent activation of K 1 channels. Evaluation of the influence of apamin, charybdotoxin, paxilline, and TRAM-34 demonstrated involvement of both intermediate and large conductance Ca 21 -activated K 1 channels.

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Structural Insights into the Atomistic Mechanisms of Action of Small Molecule Inhibitors Targeting the KCa3.1 Channel Pore

Cited by 42 publications

References 81 publications

Synthesis of Small‐Molecule Fluorescent Probes for the In Vitro Imaging of Calcium‐Activated Potassium Channel K_Ca3.1

Synthesis of Small‐Molecule Fluorescent Probes for the In Vitro Imaging of Calcium‐Activated Potassium Channel K_Ca3.1

Synthesis of Small‐Molecule Fluorescent Probes for the In Vitro Imaging of Calcium‐Activated Potassium Channel K_Ca3.1

A Comparison of the Ability of Leu⁸- and Pro⁸-Oxytocin to Regulate Intracellular Ca²⁺and Ca²⁺-Activated K⁺Channels at Human and Marmoset Oxytocin Receptors

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Structural Insights into the Atomistic Mechanisms of Action of Small Molecule Inhibitors Targeting the KCa3.1 Channel Pore

Cited by 42 publications

References 81 publications

Synthesis of Small‐Molecule Fluorescent Probes for the In Vitro Imaging of Calcium‐Activated Potassium Channel KCa3.1

Synthesis of Small‐Molecule Fluorescent Probes for the In Vitro Imaging of Calcium‐Activated Potassium Channel KCa3.1

Synthesis of Small‐Molecule Fluorescent Probes for the In Vitro Imaging of Calcium‐Activated Potassium Channel KCa3.1

A Comparison of the Ability of Leu8- and Pro8-Oxytocin to Regulate Intracellular Ca2+and Ca2+-Activated K+Channels at Human and Marmoset Oxytocin Receptors

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Synthesis of Small‐Molecule Fluorescent Probes for the In Vitro Imaging of Calcium‐Activated Potassium Channel K_Ca3.1

Synthesis of Small‐Molecule Fluorescent Probes for the In Vitro Imaging of Calcium‐Activated Potassium Channel K_Ca3.1

Synthesis of Small‐Molecule Fluorescent Probes for the In Vitro Imaging of Calcium‐Activated Potassium Channel K_Ca3.1

A Comparison of the Ability of Leu⁸- and Pro⁸-Oxytocin to Regulate Intracellular Ca²⁺and Ca²⁺-Activated K⁺Channels at Human and Marmoset Oxytocin Receptors