KCNJ5
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G protein-activated inward rectifier potassium channel 4 (GIRK-4) is a protein that in humans is encoded by the ''KCNJ5'' gene and is a type of G protein-gated ion channel.


Function

Potassium channels are present in most mammalian cells, where they participate in a wide range of physiologic responses. The protein encoded by this gene is an integral membrane protein and inward-rectifier type potassium channel. The encoded protein, which has a greater tendency to allow potassium to flow into a cell rather than out of a cell, is controlled by G-proteins. It may associate with other G-protein-activated potassium channel subunits to form a heterotetrameric pore-forming complex. In humans KCNJ5 is mainly expressed in adrenal gland and pituitary, although it is also detected at low levels in pancreas, spleen,
lung The lungs are the primary organs of the respiratory system in humans and most other animals, including some snails and a small number of fish. In mammals and most other vertebrates, two lungs are located near the backbone on either side of t ...
, heart and brain. Consistent with this expression pattern, mutations in KCNJ5/Kir3.4 can cause
familial hyperaldosteronism Familial hyperaldosteronism is a group of inherited conditions in which the adrenal glands, which are small glands located on top of each kidney, produce too much of the hormone aldosterone. Excess aldosterone causes the kidneys to retain more ...
type III and a type of
long QT syndrome Long QT syndrome (LQTS) is a condition affecting repolarization (relaxing) of the heart after a heartbeat, giving rise to an abnormally lengthy QT interval. It results in an increased risk of an irregular heartbeat which can result in fainting, d ...
.


Interactions

KCNJ5 has been shown to interact with KCNJ3.


See also

* G protein-coupled inwardly-rectifying potassium channel *
Inward-rectifier potassium ion channel Inward-rectifier potassium channels (Kir, IRK) are a specific lipid-gated subset of potassium channels. To date, seven subfamilies have been identified in various mammalian cell types, plants, and bacteria. They are activated by phosphatidylinos ...


References


Further reading

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External links

*
GTEX portal: KCNJ5 expression in human tissue
{{Ion channels, g3 Ion channels