The AMIGO1 adhesion protein activates Kv2.1 voltage sensors

Sepela, Rebecka J.; Stewart, Robert; Valencia, L.; Thapa, Parashar; Wang, Zeming; Cohen, Bruce E.; Sack, Jon T.

doi:10.1016/j.bpj.2022.03.020

Cited by 4 publications

(4 citation statements)

References 116 publications

(210 reference statements)

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“…The faster component of deactivation of RY785-sensitive currents in SCG neurons had a time constant of 16 ms ± 0.6 (mean ± SEM) at -45 mV (Fig 6 E). These results are consistent with reported biophysical properties of Kv2 channels (Kramer et al, 1998; Liu and Bean, 2014; Tilley et al, 2019; Sepela et al, 2022). Together these results show that 1 µM RY785 almost completely inhibits endogenous Kv2-like conductances in these mouse neurons, suggesting that mouse SCG neurons have few functional Kv2/KvS channels.…”

Section: Resultssupporting

confidence: 93%

“…We found that the rate of deactivation of RY785 sensitive currents in SCG neurons is 16 ms ± 0.6 (mean ± SEM) at -30 mV (Fig 6 E). These results are consistent with the biophysical properties of Kv2 channels (Kramer et al, 1998; Liu and Bean, 2014; Tilley et al, 2019; Sepela et al, 2022). Of the total conductance sensitive to RY785 and GxTX, 91 ± 4 % (mean ± SEM) was sensitive to RY785 (Kv2-like) whereas only 9 ± 4 % (mean ± SEM) appeared resistant to RY785 but sensitive to GxTX (KvS-like) (Fig 6 F).…”

Section: Resultssupporting

confidence: 89%

“…We also transfected Kv2.1-CHO cells with a member of the AMIGO family of Kv2-regulating transmembrane proteins. AMIGO1 promotes voltage sensor activation of Kv2.1 channels in these Kv2.1-CHO cells (Sepela et al, 2022). 1 μM RY785 blocked Kv2.1 conductances in cells transfected with AMIGO1, leaving 0.6 ± 1% (SEM) of current (Fig 1 C and D).…”

Section: Resultsmentioning

confidence: 99%

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A Kv2 inhibitor combination reveals native neuronal conductances consistent with Kv2/KvS heteromers

Stewart,

Marquis,

et al. 2024

Preprint

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KvS proteins are pore-forming voltage-gated potassium channel subunits that must co-assemble into heterotetramers with Kv2.1 (KCNB1) or Kv2.2 (KCNB2) subunits to form functional channels. In mammals, KvS subunits encompass the Kv5.1 (KCNF1), Kv6.1 (KCNG1), Kv6.2 (KCNG2), Kv6.3 (KCNG3), Kv6.4 (KCNG4), Kv8.1 (KCNV1), Kv8.2 (KCNV2), Kv9.1 (KCNS1), Kv9.2 (KCNS2), and Kv9.3 (KCNS3) proteins. While Kv2 proteins are broadly expressed in electrically excitable cells, KvS mRNAs are enriched in unique subsets of these cells. The physiological functions of KvS-containing channels are poorly understood and no drugs are known to selectively modulate KvS subunits. Here, we identify a pair of potent Kv2-selective inhibitors which distinguish conductances of KvS-containing channels. We find that conductances of KvS-containing channels are resistant to the pore-blocker RY785 yet remain sensitive to the voltage sensor modulator guangxitoxin-1E (GxTX). We show that this pattern of inhibitor sensitivities is consistent among subunits from Kv5, Kv6, Kv8, and Kv9 families. By deploying these inhibitors we find that mouse superior cervical ganglion neurons have conductances consistent with Kv2, but not KvS-containing channels. In contrast, mouse and human dorsal root ganglion neurons have conductances consistent with KvS/Kv2 heteromeric channels. These results provide an approach to pharmacologically distinguish KvS-containing from Kv2-only channels, and identify endogenous KvS conductances.

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Section: Resultssupporting

confidence: 93%

Section: Resultssupporting

confidence: 89%

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A Kv2 inhibitor combination reveals native neuronal conductances consistent with Kv2/KvS heteromers

Stewart,

Marquis,

et al. 2024

Preprint

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“…In the nervous system of adults, AMIGO1 contributes to regeneration and neuronal plasticity. In addition, it is known to regulate the gating characteristics of delayed voltage-dependent potassium channels 2.1 (K V 2.1) and 2.2 (K V 2.2), with importance for generating action potentials and neuronal excitability [32][33][34][35]. The deletion of AMIGO1 or the reduction of its expression leads to reduced axonal guiding and development in mice and zebrafish [36].…”

Section: Discussionmentioning

confidence: 99%

Analysis of Free Circulating Messenger Ribonucleic Acids in Serum Samples from Late-Onset Spinal Muscular Atrophy Patients Using nCounter NanoString Technology

Leo,

Schmitt,

Mairinger

et al. 2023

Cells

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5q-related Spinal muscular atrophy (SMA) is a hereditary multi-systemic disorder leading to progressive muscle atrophy and weakness caused by the degeneration of spinal motor neurons (MNs) in the ventral horn of the spinal cord. Three SMN-enhancing drugs for SMA treatment are available. However, even if these drugs are highly effective when administrated early, several patients do not benefit sufficiently or remain non-responders, e.g., adults suffering from late-onset SMA and starting their therapy at advanced disease stages characterized by long-standing irreversible loss of MNs. Therefore, it is important to identify additional molecular targets to expand therapeutic strategies for SMA treatment and establish prognostic biomarkers related to the treatment response. Using high-throughput nCounter NanoString technology, we analyzed serum samples of late-onset SMA type 2 and type 3 patients before and six months under nusinersen treatment. Four genes (AMIGO1, CA2, CCL5, TLR2) were significantly altered in their transcript counts in the serum of patients, where differential expression patterns were dependent on SMA subtype and treatment response, assessed with outcome scales. No changes in gene expression were observed six months after nusinersen treatment, compared to healthy controls. These alterations in the transcription of four genes in SMA patients qualified those genes as potential SMN-independent therapeutic targets to complement current SMN-enhancing therapies.

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A Kv2 inhibitor combination reveals native neuronal conductances consistent with Kv2/KvS heteromers

Stewart,

Marquis,

et al. 2024

Preprint

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KvS proteins are voltage-gated potassium channel subunits that form functional channels when assembled into heterotetramers with Kv2.1 ( KCNB1 ) or Kv2.2 ( KCNB2 ). Mammals have 10 KvS subunits: Kv5.1 ( KCNF1 ), Kv6.1 ( KCNG1 ), Kv6.2 ( KCNG2 ), Kv6.3 ( KCNG3 ), Kv6.4 ( KCNG4 ), Kv8.1 ( KCNV1 ), Kv8.2 ( KCNV2 ), Kv9.1 ( KCNS1 ), Kv9.2 ( KCNS2 ), and Kv9.3 ( KCNS3 ). Electrically excitable cells broadly express channels containing Kv2 subunits and most neurons have substantial Kv2 conductance. However, whether KvS subunits contribute to these conductances has not been clear, leaving the physiological roles of KvS subunits poorly understood. Here, we identify that two potent Kv2 inhibitors, used in combination, can distinguish conductances of Kv2/KvS channels and Kv2-only channels. We find that Kv5, Kv6, Kv8, or Kv9-containing channels are resistant to the Kv2-selective pore-blocker RY785 yet remain sensitive to the Kv2-selective voltage sensor modulator guangxitoxin-1E (GxTX). Using these inhibitors in mouse superior cervical ganglion neurons, we find that little of the Kv2 conductance is carried by KvS-containing channels. In contrast, conductances consistent with KvS-containing channels predominate over Kv2-only channels in mouse and human dorsal root ganglion neurons. These results establish an approach to pharmacologically distinguish conductances of Kv2/KvS heteromers from Kv2-only channels, enabling investigation of the physiological roles of endogenous KvS subunits. These findings suggest that drugs targeting KvS subunits could modulate electrical activity of subsets of Kv2-expressing cell types.

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The AMIGO1 adhesion protein activates Kv2.1 voltage sensors

Cited by 4 publications

References 116 publications

A Kv2 inhibitor combination reveals native neuronal conductances consistent with Kv2/KvS heteromers

A Kv2 inhibitor combination reveals native neuronal conductances consistent with Kv2/KvS heteromers

Analysis of Free Circulating Messenger Ribonucleic Acids in Serum Samples from Late-Onset Spinal Muscular Atrophy Patients Using nCounter NanoString Technology

A Kv2 inhibitor combination reveals native neuronal conductances consistent with Kv2/KvS heteromers

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