Absence of KCNQ1-dependent K+ fluxes in proximal tubular cells of frog kidney

Cemerikic, Dusan; Nesovic-Ostojic, Jelena; Popadić, Dušan; Knežević, Aleksandra; Dragovic, Simon; Milovanović, Aleksandar; Milovanović, Jovica

doi:10.1016/j.cbpa.2007.08.010

Cited by 4 publications

(5 citation statements)

References 37 publications

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“…12 This indicates that KCNQ1-dependent K + movement from the cell to the lumen contributes to the maintenance of the electrical driving force for Na + -coupled transport in proximal tubule. Non expression of KCNQ1 K + channel on proximal tubules in frog kidney in the present study confirms our previous results of absence of this K + channel protein 13 on proximal epithelial cells in the same animal.…”

Section: Discussionsupporting

confidence: 93%

“…Also, RT-PCR analysis in the same study revealed that KCNQ1 mRNA is not expressed in the proximal tubules of frog kidney at a detectable level, although revealed a detectable KCNQ1 expression in the frog heart. 13 Used specimens of the frog kidney tissue for RT-PCR analysis were from lateral upper pole of the frog kidney which contained proximal tubules. So far, there were no similar findings in the frog kidney, but many scientists find KCNQ1 channels in rat and mouse kidney.…”

Section: Discussionmentioning

confidence: 99%

“…12 Our previous results confirmed the absence of KCNQ1 K + secretory fluxes in the proximal cells of frog kidney with RT-PCR analysis which revealed that KCNQ1 mRNA is not expressed in the proximal tubules of frog kidney at a detectable level, as used specimens of the frog kidney tissue for RT-PCR analysis were from lateral upper pole of the frog kidney which contained proximal tubules. 13 …”

Section: Introductionmentioning

confidence: 99%

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Differential expression of KCNQ1 K+ channel in tubular cells of frog kidney

Ćirović¹,

Marković-Lipkovski²,

Todorović³

et al. 2010

Eur J Histochem

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The aim of this study was to evaluate KCNQ1 K+ channel expression in the frog kidney of Rana esculenta. KCNQ1 K+ channel, also known as KvLQT1, is the pore forming α-subunit of the IKs K+ channel, a delayed rectifier voltage-gated K+ channel, which has an important role in water and salt transport in the kidney and gastrointestinal tract. The expression of KCNQ1 K+ channel along tubular epithelium differs from species to species. In the present study the expression of KCNQ1 K+ channel in the frog kidney has been demonstrated by immunohistochemistry. The presence of KCNQ1 K+ channel was demonstrated in the epithelial cells of distal convoluted tubule and collecting duct. However, the pattern of expression of KCNQ1 K+ channel differs between distal convoluted tubules and collecting duct. All epithelial cells of distal convoluted tubules revealed basolateral expression of KCNQ1 K+ channel. On the contrary, only the single cells of collecting duct, probably intercalated cells, showed diffuse cell surface staining with antibodies against KCNQ1 K+ channel. These findings suggest that KCNQ1 K+ channel has cell-specific roles in renal potassium ion transport.

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Section: Discussionsupporting

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Differential expression of KCNQ1 K+ channel in tubular cells of frog kidney

Ćirović¹,

Marković-Lipkovski²,

Todorović³

et al. 2010

Eur J Histochem

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“…For example, in mouse the KCNQ1 K + (KvLQT1, Kv7.1) channel is expressed in renal proximal tubules (JESPERSEN et al 2004; 2005), on the luminal membrane, and the TASK2 K + channel is present on the basolateral membrane of the proximal tubule and papillary collecting ducts (WARTH et al 2004). We did not prove KCNQ1 expression in the proximal cell tubule of the frog kidney, but we found evidence that this channel exists in the distal convoluted and collecting duct (CEMERIKIC et al 2007). The function of the KCNQ1 K + channel in the kidney has not been fully established, but KCNQ1 knockout mice were found to suffer from lower potassium sera level, urinary and faecal salt wasting and volume depletion, thereby indicating an important role for the IsK (KCNQ1) channel and renal function (VAL-LON et al 2005).…”

Section: Discussionmentioning

confidence: 64%

Immunolocalization of the TASK2 Potassium Channel in Frog Kidney*

Nesovic-Ostojic

Marković-Lipkovski

Todorović

et al. 2016

folia biol (krakow)

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TASK2 (K 2P 5.1, KCNK5) is a two-pore domain K + channel belonging to the TALK subgroup of the K 2P family of proteins. TASK2 expression has been reported in a variety of cells and tissues ranging from kidney to immune cells and including specific neurons, its proposed functions spanning from involvement in the regulation of cell volume to control of excitability. The purpose of this study was to determine the tubule location of the TASK2 K + channel protein in frog kidney applying polyclonal antibody against the carboxyl terminus of human TASK2 (KCNK5) protein. Immunohistochemical analysis revealed that TASK2 is expressed on distal tubules and proximal epithelial cells. TASK2 is strongly expressed predominantly on the luminal part of the proximal epithelial cells and slightly cytoplasmatic staining is expressed. Distal tubules showed diffuse cytoplasmatic staining as well as slight staining on the apical parts of the cells. These findings suggest that the TASK2 K + channel has cell-specific roles in renal potassium ion transport.

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“…In amphibians, TASK-2 channel is expressed predominantly on the luminal part of the proximal epithelial cell. One of the possibilities is that this channel in the proximal tubule of frog kidney functions instead of the KCNQ 1 K + channel (17,18). Activation by extracellular alkalinization has been associated with a role of TASK-2 in kidney proximal tubule bicarbonate reabsorption.…”

Section: Introductionmentioning

confidence: 99%

Potassium channels in renal proximal tubule

Kovačević¹,

Nesovic-Ostojic²

2017

Med podmladak

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Potassium channels are a diverse family of membrane proteins which are present within all cells of the body. They contain two subunits α, which determine the structure of the channel, and β, which can modify the properties of the channel. Those transmembrane proteins take part in K + movement across cell membranes, via a highly selective pore. The kidneys have crucial role in maintaining total body potassium content, by matching its intake and excretion. K + absorption in the proximal tubule is primarily passive and proportional to Na + and water, so that changes in fluid and potassium transport are closely coupled. Proximal tubular K + channels are crucial for the maintenance of a hyperpolarized membrane voltage. In leaky epithelia, such as the proximal tubule, the hyperpolarization of the basolateral membrane also results in the hyperpolarization of the apical membrane, due to increase in the K + conductance of that barrier. They are also involved in regulating cell volume and in recycling potassium across the basolateral membrane. K + channels of the KCNK and KCNJ gene families have been discovered in the basolateral membrane cell of various species. One of the primary functions of basolateral K + channels is to recycle K + across the basolateral membrane for proper function of the Na + -K + -ATPase. Activation by extracellular alkalinization has been associated with a role of TASK-2 in kidney proximal tubule bicarbonate reabsorption. In renal proximal tubules, luminal K + channels play an important role for restoring the driving force of Na + -coupled transport systems (amino acids, glucose), which depolarize the luminal membrane. Some of these luminal K + channels are activated directly by the transport-associated depolarization; others are regulated by mediators, second messenger pathways and cell volume. Key words:Proximal tubule, Potassium, Channels Medicinski podmladak / Medical Youth Kovačević S. et al. Potassium channels in renal proximal tubule. MedPodml 2017, 68(2):14-19 15 SAŽETAKKalijumski kanali predstavljaju raznoliku familiju membranskih proteina, prisutnih u svim ćelijama. Ovi transmembranski proteini posreduju u pasivnom kretanju kalijumovih jona kroz ćelijsku membranu putem visokoselektivnih pora. Regulacija kalijumske ravnoteže u organizmu zavisi od održavanja jedinstvenog raspoređivanja kalijuma između intra-i ekstraćelijskog odeljka i adekvatne ekskrecije putem bubrega. Apsorpcija kalijuma u proksimalnom tubulu prvenstveno je pasivna i proporcionalna apsorpciji natrijuma i vode. Kalijumski kanali u ćelijama proksimalnog tubula imaju ključnu ulogu u stvaranju negativnog membranskog potencijala ćelije. U propustljivim epitelima, kao što je epitel proksimalnog tubula, hiperpolarizacija bazolateralne membrane, usled povećanja provodljivosti kalijuma (K + ), takođe rezultira hiperpolarizacijom apikalne membrane. Kalijumski kanali proksimalnih tubula su uključeni u regulaciju ćelijskog volumena, kao i u kruženje kalijuma kroz bazolateralnu membranu. Različiti jonski kanali i transporter...

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Absence of KCNQ1-dependent K+ fluxes in proximal tubular cells of frog kidney

Cited by 4 publications

References 37 publications

Differential expression of KCNQ1 K+ channel in tubular cells of frog kidney

Differential expression of KCNQ1 K+ channel in tubular cells of frog kidney

Immunolocalization of the TASK2 Potassium Channel in Frog Kidney*

Potassium channels in renal proximal tubule

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