Up-Regulation of Kir2.1 (KCNJ2) by the Serum &amp; Glucocorticoid Inducible SGK3

Muñoz, Carlos; Pakladok, Tatsiana; Almilaji, Ahmad; Elvira, Bernat; Decher, Niels; Shumilina, Ekaterina; Läng, Florian

doi:10.1159/000358629

Cited by 17 publications

(16 citation statements)

References 58 publications

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“…Xenopus oocytes were prepared as previously described [34,35]. cRNA (4.6 ng) encoding either AMPKα1-HA + AMPKβ1-Flag + AMPKγ1-HA (AMPK WT ), or AMPKα1-HA + AMPKβ1-Flag + R70Q AMPKγ1-HA (AMPK γR70Q ) or K45R AMPKα1KD-HA + AMPKβ1-Flag +AMPKγ1-HA (AMPK αK45R ) were injected on the first day and 23 ng of cRNA encoding Cx43-eGFP on the third day after preparation of the Xenopus oocytes [19,36].…”

Section: Methodsmentioning

confidence: 99%

AMP-Activated Protein Kinase α1 Regulates Cardiac Gap Junction Protein Connexin 43 and Electrical Remodeling Following Pressure Overload

Alesutan

Voelkl²,

Stöckigt³

et al. 2015

Cell Physiol Biochem

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Background/Aims: Adenosine 5'-monophosphate (AMP)-activated protein kinase (Ampk) modulates a wide array of cellular functions and regulates various ion channels and transporters. In failing human hearts an increased Ampkα1 activity was observed. The present study aimed to uncover the impact of Ampkα1 on cardiac electrical remodeling. Methods: Gene-targeted mice lacking functional Ampkα1 (Ampkα1-/-) and corresponding wild-type mice were exposed to pressure overload by “transverse aortic constriction” (TAC). In vivo electrophysiology was performed with a single catheter technique, myocardial conduction velocities and conduction characteristics investigated in isolated hearts, transcript levels quantified by RT-PCR and protein abundance determined by Western blotting. Moreover, connexin 43 (Cx43) was expressed in Xenopus oocytes with or without coexpression of wild-type or mutant AMPK and Cx43 protein abundance quantified utilizing confocal microscopy. Results: TAC treatment increased Ampkα1 protein expression in cardiac tissue from wild-type mice. TAC further increased left ventricular conduction inhomogeneity and triggered conduction blocks, effects blunted in the Ampkα1^-/- mice. TAC treatment decreased Cx43 protein abundance in cardiac tissue, an effect significantly blunted in the Ampkα1^-/- mice. TAC treatment did not modify Cx43 mRNA levels but increased ubiquitination of Cx43 protein, an effect mitigated by Ampkα1 deficiency. As shown in Xenopus oocytes, Cx43 cell membrane protein abundance was significantly downregulated by wild-type AMPK^WT and constitutively active AMPK^γR70Q, but not by catalytically inactive AMPK^αK45R. Conclusion: Ampkα1 stimulates ubiquitination of the gap junction protein Cx43, thereby contributing to gap junction remodeling following pressure overload.

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Section: Methodsmentioning

confidence: 99%

AMP-Activated Protein Kinase α1 Regulates Cardiac Gap Junction Protein Connexin 43 and Electrical Remodeling Following Pressure Overload

Alesutan

Voelkl²,

Stöckigt³

et al. 2015

Cell Physiol Biochem

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“…Constructs encoding human wild-type EAAT3 [38,39], wild-type SPAK, constitutively active T233E SPAK, WNK-insensitive T233A SPAK, catalytically inactive D212A SPAK [6,27], wild-type OSR1, constitutively active T185E OSR1, WNK-insensitive T185A OSR1 and catalytically inactive D164A OSR1 [40] were used for the generation of cRNA as described previously [41,42]. The constructs were a gift from Prof. Dario Alessi (University of Dundee, UK).…”

Section: Methodsmentioning

confidence: 99%

“…In all Ussing chamber experiments, the transepithelial potential difference (Vt) was determined continuously and the transepithelial resistance (Rt) was estimated from the voltage deflections (ΔVt) elicited by imposing test currents (I t ). The resulting Rt was calculated according to Ohm's law [42]. …”

Section: Methodsmentioning

confidence: 99%

SPAK and OSR1 Sensitivity of Excitatory Amino Acid Transporter EAAT3

Borrás

Salker²,

Elvira³

et al. 2015

Nephron

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Background/Aims: Kinases involved in the regulation of epithelial transport include SPAK (SPS1-related proline/alanine-rich kinase) and OSR1 (oxidative stress-responsive kinase 1). SPAK and OSR1 are both regulated by WNK (with-no-K(Lys)) kinases. The present study explored whether SPAK and/or OSR1 influence the excitatory amino acid transporter EAAT3, which accomplishes glutamate and aspartate transport in kidney, intestine and brain. Methods: cRNA encoding EAAT3 was injected into Xenopus laevis oocytes with or without additional injection of cRNA encoding wild-type SPAK, constitutively active ^T233ESPAK, WNK insensitive ^T233ASPAK, catalytically inactive ^D212ASPAK, wild-type OSR1, constitutively active ^T185EOSR1, WNK insensitive ^T185AOSR1 and catalytically inactive ^D164AOSR1. Glutamate-induced current was taken as measure of electrogenic glutamate transport and was quantified utilizing dual electrode voltage clamp. Furthermore, Ussing chamber was employed to determine glutamate transport in the intestine from gene-targeted mice carrying WNK insensitive SPAK (spak^tg/tg) and from corresponding wild-type mice (spak^+/+). Results: EAAT3 activity was significantly decreased by wild-type SPAK and ^T233ESPAK, but not by ^T233ASPAK and ^D212ASPAK. SPAK decreased maximal transport rate without affecting significantly affinity of the carrier. Similarly, EAAT3 activity was significantly downregulated by wild-type OSR1 and ^T185EOSR1, but not by ^T185AOSR1 and ^D164AOSR1. Again OSR1 decreased maximal transport rate without affecting significantly affinity of the carrier. Intestinal electrogenic glutamate transport was significantly lower in spak^+/+ than in spak^tg/tg mice. Conclusion: Both, SPAK and OSR1 are negative regulators of EAAT3 activity.

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“…The data were filtered at 2 kHz and recorded with a Digidata 1322A A/D-D/A converter and ClampexV .9.2 software for data acquisition (Axon Instruments) [47,48]. The analysis of the data was performed with Clampfit 9.2 (Axon Instruments) software [49,50]. …”

Section: Methodsmentioning

confidence: 99%

Regulation of the Voltage Gated K+ Channel Kv1.3 by Recombinant Human Klotho Protein

Almilaji

Honisch

Liu

et al. 2014

Kidney Blood Press Res

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Background/Aims: Klotho, a protein mainly produced in the kidney and released into circulating blood, contributes to the negative regulation of 1,25(OH)₂D₃ formation and is thus a powerful regulator of mineral metabolism. As β-glucuronidase, alpha Klotho protein further regulates the stability of several carriers and channels in the plasma membrane and thus regulates channel and transporter activity. Accordingly, alpha Klotho protein participates in the regulation of diverse functions seemingly unrelated to mineral metabolism including lymphocyte function. The present study explored the impact of alpha Klotho protein on the voltage gated K⁺ channel K_v1.3. Methods: cRNA encoding K_v1.3 (KCNA3) was injected into Xenopus oocytes and depolarization induced outward current in K_v1.3 expressing Xenopus oocytes determined utilizing dual electrode voltage clamp. Experiments were performed without or with prior treatment with recombinant human Klotho protein (50 ng/ml, 24 hours) in the absence or presence of a β-glucuronidase inhibitor D-saccharic acid-1,4-lactone (DSAL, 10 µM). Moreover, the voltage gated K⁺ current was determined in Jcam lymphoma cells by whole cell patch clamp following 24 hours incubation without or with recombinant human Klotho protein (50 ng/ml, 24 hours). K_v1.3 protein abundance in Jcam cells was determined utilising fluorescent antibodies in flow cytometry. Results: In K_v1.3 expressing Xenopus oocytes the K_v1.3 currents and the protein abundance of K_v1.3 were both significantly enhanced after treatment with recombinant human Klotho protein (50 ng/ml, 24 hours), an effect reversed by presence of DSAL. Moreover, treatment with recombinant human Klotho protein increased K_v currents and K_v1.3 protein abundance in Jcam cells. Conclusion: Alpha Klotho protein enhances K_v1.3 channel abundance and K_v1.3 currents in the plasma membrane, an effect depending on its β-glucuronidase activity.

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Up-Regulation of K_ir2.1 (KCNJ2) by the Serum & Glucocorticoid Inducible SGK3

Cited by 17 publications

References 58 publications

AMP-Activated Protein Kinase α1 Regulates Cardiac Gap Junction Protein Connexin 43 and Electrical Remodeling Following Pressure Overload

AMP-Activated Protein Kinase α1 Regulates Cardiac Gap Junction Protein Connexin 43 and Electrical Remodeling Following Pressure Overload

SPAK and OSR1 Sensitivity of Excitatory Amino Acid Transporter EAAT3

Regulation of the Voltage Gated K<sup>+</sup> Channel K<sub>v1.3</sub> by Recombinant Human Klotho Protein

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