Immunolocalization of the TASK2 Potassium Channel in Frog Kidney*

Nesovic-Ostojic, Jelena; Marković-Lipkovski, Jasmina; Todorović, Jovan; Ćirović, Sanja; Kovačević, Sanjin; Paunović, Aleksandra; Cemerikic, Dusan; Milovanović, Aleksandar

doi:10.3409/fb64_3.183

Cited by 1 publication

(1 citation statement)

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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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Section: Introductionmentioning

confidence: 99%