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The sodium–potassium pump a critical enzyme for regulating sodium and potassium levels in cells. Potassium is the main intracellular ion for all types of cells, while having a major role in maintenance of fluid and electrolyte balance. [1] [2] Potassium is necessary for the function of all living cells and is thus present in all plant and ...
BK channels (big potassium), are large conductance calcium-activated potassium channels, [1] also known as Maxi-K, slo1, or Kca1.1. BK channels are voltage-gated potassium channels that conduct large amounts of potassium ions (K + ) across the cell membrane , hence their name, big potassium .
Potassium channels function to conduct potassium ions down their electrochemical gradient, doing so both rapidly (up to the diffusion rate of K + ions in bulk water) and selectively (excluding, most notably, sodium despite the sub-angstrom difference in ionic radius). [4] Biologically, these channels act to set or reset the resting potential in ...
K ir export surplus potassium into collecting tubules for removal in the urine, or alternatively may be involved in the reuptake of potassium back into the body. neurons and in heart cells: G-protein activated IRKs (K ir 3) are important regulators, modulated by neurotransmitters. A mutation in the GIRK2 channel leads to the weaver mouse mutation.
Potassium homeostasis denotes the maintenance of the total body potassium content, plasma potassium level, and the ratio of the intracellular to extracellular potassium concentrations within narrow limits, in the face of pulsatile intake (meals), obligatory renal excretion, and shifts between intracellular and extracellular compartments.
Simple diagram of a Large Conductance calcium-activated potassium channel (BK). A similar structure can be hypothesized for the other subtypes in this family of channels. Knowing the structure of these channels can provide insight into their function and mechanism of gating. They are made up of two different subunits, alpha and beta.
Four genes have been identified as members of the K ATP gene family. The sur1 and kir6.2 genes are located in chr11p15.1 while kir6.1 and sur2 genes reside in chr12p12.1. The kir6.1 and kir6.2 genes encode the pore-forming subunits of the K ATP channel, with the SUR subunits being encoded by the sur1 (SUR1) gene or selective splicing of the sur2 gene (SUR2A and SUR2B).
The sodium–potassium pump (sodium–potassium adenosine triphosphatase, also known as Na + /K +-ATPase, Na + /K + pump, or sodium–potassium ATPase) is an enzyme (an electrogenic transmembrane ATPase) found in the membrane of all animal cells. It performs several functions in cell physiology. The Na + /K +-ATPase enzyme is active (i.e. it ...