G-protein βγ subunits are positive regulators of Kv7.4 and native vascular Kv7 channel activity

Stott, Jennifer B.; Povstyan, Oleksandr V.; Carr, Georgina; Barrese, Vincenzo; Greenwood, Iain A.

doi:10.1073/pnas.1418605112

Cited by 54 publications

(75 citation statements)

References 30 publications

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“…As there is considerable evidence that Kv7 channels regulate vascular smooth muscle contractility and contribute to the vasodilator response of many endogenous agents, 3,4,6–15,24,26–28 the present study implicates miR153 as a determinant of vascular tone and potentially a novel therapeutic target for the treatment of hypertension.…”

Section: Discussionmentioning

confidence: 71%

MicroRNA-153 targeting of KCNQ4 contributes to vascular dysfunction in hypertension

et al. 2016

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AimsKv7.4, a voltage-dependent potassium channel expressed throughout the vasculature, controls arterial contraction and is compromised in hypertension by an unknown mechanism. MicroRNAs (miRs) are post-transcriptional regulators of protein production and are altered in disease states such as hypertension. We investigated whether miRs regulate Kv7.4 expression.Methods and resultsIn renal and mesenteric arteries (MAs) of the spontaneously hypertensive rat (SHR), Kv7.4 protein decreased compared with the normotensive (NT) rat without a decrease in KCNQ4 mRNA, inferring that Kv7.4 abundance was determined by post-transcriptional regulation. In silico analysis of the 3′ UTR of KCNQ4 revealed seed sequences for miR26a, miR133a, miR200b, miR153, miR214, miR218, and let-7d with quantitative polymerase chain reaction showing miR153 increased in those arteries from SHRs that exhibited decreased Kv7.4 levels. Luciferase reporter assays indicated a direct targeting effect of miR153 on the 3′ UTR of KCNQ4. Introduction of high levels of miR153 to MAs increased vascular wall thickening and reduced Kv7.4 expression/Kv7 channel function compared with vessels receiving a non-targeting miR, providing a proof of concept of Kv7.4 regulation by miR153.ConclusionThis study is the first to define a role for aberrant miR153 contributing to the hypertensive state through targeting of KCNQ4 in an animal model of hypertension, raising the possibility of the use of miR153-related therapies in vascular disease.

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Section: Discussionmentioning

confidence: 71%

MicroRNA-153 targeting of KCNQ4 contributes to vascular dysfunction in hypertension

et al. 2016

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“…The effect of mSIRK on [ 3 H]-DA efflux was blocked by the DAT inhibitors cocaine, mazindol, or GBR12935 (Figure 1d and Supplementary Figure S1). Finally, we tested the effect of mSIRK on DA efflux in the presence of two different blockers of Gβγ signaling; the small molecule gallein that binds to Gβγ and disrupts Gβγ signaling to effectors 16,18 and Kpept, a Gβγ scavenger peptide derived from a Gβγ-regulated potassium channel, GRK4, 19,20 fused to a TAT sequence for cell membrane penetration (TAT-Kpept) (Figures 1e and f). Gallein, in a dose-dependent manner, reduced DA efflux induced by 10 μM mSIRK (Figure 1e).…”

Section: Resultsmentioning

confidence: 99%

Gβγ subunit activation promotes dopamine efflux through the dopamine transporter

et al. 2017

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The dopamine transporter (DAT) is an important regulator of brain dopamine (DA) homeostasis, controlling the intensity and duration of DA signaling. DAT is the target for psychostimulants—like cocaine and amphetamine—and plays an important role in neuropsychiatric disorders, including attention-deficit hyperactivity disorder and drug addiction. Thus, a thorough understanding of the mechanisms that regulate DAT function is necessary for the development of clinical interventions to treat DA-related brain disorders. Previous studies have revealed a plethora of protein–protein interactions influencing DAT cellular localization and activity, suggesting that the fine-tuning of DA homeostasis involves multiple mechanisms. We recently reported that G-protein beta-gamma (Gβγ) subunits bind directly to DAT and decrease DA clearance. Here we show that Gβγ induces the release of DA through DAT. Specifically, a Gβγ-binding/activating peptide, mSIRK, increases DA efflux through DAT in heterologous cells and primary dopaminergic neurons in culture. Addition of the Gβγ inhibitor gallein or DAT inhibitors prevents this effect. Residues 582 to 596 in the DAT carboxy terminus were identified as the primary binding site of Gβγ. A TAT peptide containing the Gβγ-interacting domain of DAT blocked the ability of mSIRK to induce DA efflux, consistent with a direct interaction of Gβγ with the transporter. Finally, activation of a G-protein-coupled receptor, the muscarinic M5R, results in DAT-mediated DA efflux through a Gβγ-dependent mechanism. Collectively, our data show that Gβγ interacts with DAT to promote DA efflux. This novel mechanism may have important implications in the regulation of brain DA homeostasis.

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“…Importantly, this study highlights a novel role for the KCNE4 subunit in mediating β-adrenoceptor responses in the mesenteric artery. Kv7 channels in the vasculature contribute to different Gs-coupled receptor mediated relaxations, yet the exact signaling mechanisms are still unclear (7, 11, 12, 14, 15). Following Gs coupled-receptor activation, a cAMP-dependent mechanism (11) and the βγ-subunits (15) have both been shown to enhance Kv7.4/Kv7.5 channel activity.…”

Section: Discussionmentioning

confidence: 99%

Kcne4 Deletion Sex-Dependently Alters Vascular Reactivity

Abbott

Jepps²

2016

J Vasc Res

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Voltage-gated potassium (Kv) channels formed by Kv7 (KCNQ) α-subunits are recognized as crucial for vascular smooth muscle function, in addition to their established roles in the heart (Kv7.1) and the brain (Kv7.2-5). In vivo, Kv7 α-subunits are often regulated by KCNE subfamily ancillary (β) subunits. We investigated the effects of targeted germline Kcne4 deletion on mesenteric artery reactivity in adult male and female mice. Kcne4 deletion increased mesenteric artery contractility in response to α-adrenoceptor agonist methoxamine, and decreased responses to Kv7.2-7.5 channel activator ML213, in male but not female mice. In contrast, Kcne4 deletion markedly decreased vasorelaxation in response to isoprenaline in both male and female mice. Kcne4 expression was 2-fold lower in the female versus the male mouse mesenteric artery, and Kcne4 deletion elicited only moderate changes of other Kcne transcripts, with no striking sex-specific differences. However, Kv7.4 protein expression in females was twice that in males, and was reduced in both sexes by Kcne4 deletion. Our findings confirm a crucial role for KCNE4 in regulation of Kv7 channel activity to modulate vascular tone, and provide the first known molecular mechanism for sex-specificity of this modulation that has important implications for vascular reactivity and may underlie sex-specific susceptibility to cardiovascular diseases.

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G-protein βγ subunits are positive regulators of Kv7.4 and native vascular Kv7 channel activity

Cited by 54 publications

References 30 publications

MicroRNA-153 targeting of KCNQ4 contributes to vascular dysfunction in hypertension

MicroRNA-153 targeting of KCNQ4 contributes to vascular dysfunction in hypertension

Gβγ subunit activation promotes dopamine efflux through the dopamine transporter

Kcne4 Deletion Sex-Dependently Alters Vascular Reactivity

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