KCNJ5 explained

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.^{[1] [2]}

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, heart and brain.^[3] Consistent with this expression pattern, mutations in KCNJ5/Kir3.4 can cause familial hyperaldosteronism type III and a type of long QT syndrome.

Interactions

KCNJ5 has been shown to interact with KCNJ3.^{[4] [5]}

See also

• G protein-coupled inwardly-rectifying potassium channel
• Inward-rectifier potassium ion channel

Further reading

• Zhuo ML, Huang Y, Liu DP, Liang CC . KATP channel: relation with cell metabolism and role in the cardiovascular system . The International Journal of Biochemistry & Cell Biology . 37 . 4 . 751–64 . April 2005 . 15694835 . 10.1016/j.biocel.2004.10.008 .
• Tucker SJ, James MR, Adelman JP . Assignment of KATP-1, the cardiac ATP-sensitive potassium channel gene (KCNJ5), to human chromosome 11q24 . Genomics . 28 . 1 . 127–8 . July 1995 . 7590741 . 10.1006/geno.1995.1121 .
• Ashford ML, Bond CT, Blair TA, Adelman JP . Cloning and functional expression of a rat heart KATP channel . Nature . 378 . 6559 . 792 . 1996 . 8524415 . 10.1038/378792a0 . free .
• Spauschus A, Lentes KU, Wischmeyer E, Dissmann E, Karschin C, Karschin A . A G-protein-activated inwardly rectifying K+ channel (GIRK4) from human hippocampus associates with other GIRK channels . The Journal of Neuroscience . 16 . 3 . 930–8 . February 1996 . 8558261 . 10.1523/JNEUROSCI.16-03-00930.1996. 6578796 . free .
• Iizuka M, Kubo Y, Tsunenari I, Pan CX, Akiba I, Kono T . Functional characterization and localization of a cardiac-type inwardly rectifying K+ channel . Receptors & Channels . 3 . 4 . 299–315 . 1996 . 8834003 .
• Chan KW, Langan MN, Sui JL, Kozak JA, Pabon A, Ladias JA, Logothetis DE . A recombinant inwardly rectifying potassium channel coupled to GTP-binding proteins . The Journal of General Physiology . 107 . 3 . 381–97 . March 1996 . 8868049 . 2216996 . 10.1085/jgp.107.3.381 .
• Huang CL, Jan YN, Jan LY . Binding of the G protein betagamma subunit to multiple regions of G protein-gated inward-rectifying K+ channels . FEBS Letters . 405 . 3 . 291–8 . April 1997 . 9108307 . 10.1016/S0014-5793(97)00197-X . 44072628 . 1997FEBSL.405..291H .
• Kanzaki M, Lindorfer MA, Garrison JC, Kojima I . Activation of the calcium-permeable cation channel CD20 by alpha subunits of the Gi protein . The Journal of Biological Chemistry . 272 . 23 . 14733–9 . June 1997 . 9169438 . 10.1074/jbc.272.23.14733 . free .
• Wischmeyer E, Döring F, Wischmeyer E, Spauschus A, Thomzig A, Veh R, Karschin A . Subunit interactions in the assembly of neuronal Kir3.0 inwardly rectifying K+ channels . Molecular and Cellular Neurosciences . 9 . 3 . 194–206 . 1997 . 9245502 . 10.1006/mcne.1997.0614 . 8455396 .
• Krapivinsky G, Kennedy ME, Nemec J, Medina I, Krapivinsky L, Clapham DE . Gbeta binding to GIRK4 subunit is critical for G protein-gated K+ channel activation . The Journal of Biological Chemistry . 273 . 27 . 16946–52 . July 1998 . 9642257 . 10.1074/jbc.273.27.16946 . free .
• Corey S, Clapham DE . Identification of native atrial G-protein-regulated inwardly rectifying K+ (GIRK4) channel homomultimers . The Journal of Biological Chemistry . 273 . 42 . 27499–504 . October 1998 . 9765280 . 10.1074/jbc.273.42.27499 . free .
• Kennedy ME, Nemec J, Corey S, Wickman K, Clapham DE . GIRK4 confers appropriate processing and cell surface localization to G-protein-gated potassium channels . The Journal of Biological Chemistry . 274 . 4 . 2571–82 . January 1999 . 9891030 . 10.1074/jbc.274.4.2571 . free .
• Schoots O, Wilson JM, Ethier N, Bigras E, Hebert TE, Van Tol HH . Co-expression of human Kir3 subunits can yield channels with different functional properties . Cellular Signalling . 11 . 12 . 871–83 . December 1999 . 10659995 . 10.1016/S0898-6568(99)00059-5 .
• He C, Yan X, Zhang H, Mirshahi T, Jin T, Huang A, Logothetis DE . Identification of critical residues controlling G protein-gated inwardly rectifying K(+) channel activity through interactions with the beta gamma subunits of G proteins . The Journal of Biological Chemistry . 277 . 8 . 6088–96 . February 2002 . 11741896 . 10.1074/jbc.M104851200 . free .
• Ma D, Zerangue N, Raab-Graham K, Fried SR, Jan YN, Jan LY . Diverse trafficking patterns due to multiple traffic motifs in G protein-activated inwardly rectifying potassium channels from brain and heart . Neuron . 33 . 5 . 715–29 . February 2002 . 11879649 . 10.1016/S0896-6273(02)00614-1 . 10459917 . free .
• Lavine N, Ethier N, Oak JN, Pei L, Liu F, Trieu P, Rebois RV, Bouvier M, Hebert TE, Van Tol HH . G protein-coupled receptors form stable complexes with inwardly rectifying potassium channels and adenylyl cyclase . The Journal of Biological Chemistry . 277 . 48 . 46010–9 . November 2002 . 12297500 . 10.1074/jbc.M205035200 . free .
• Shankar H, Murugappan S, Kim S, Jin J, Ding Z, Wickman K, Kunapuli SP . Role of G protein-gated inwardly rectifying potassium channels in P2Y12 receptor-mediated platelet functional responses . Blood . 104 . 5 . 1335–43 . September 2004 . 15142872 . 10.1182/blood-2004-01-0069 . free .

External links

• • GTEX portal: KCNJ5 expression in human tissue

Notes and References

1. Kubo Y, Adelman JP, Clapham DE, Jan LY, Karschin A, Kurachi Y, Lazdunski M, Nichols CG, Seino S, Vandenberg CA . International Union of Pharmacology. LIV. Nomenclature and molecular relationships of inwardly rectifying potassium channels . Pharmacological Reviews . 57 . 4 . 509–26 . December 2005 . 16382105 . 10.1124/pr.57.4.11 . 11588492 .
2. Web site: Entrez Gene: KCNJ5 potassium inwardly-rectifying channel, subfamily J, member 5.
3. Web site: Gtexportal. GETEX portal.
4. Huang CL, Jan YN, Jan LY . Binding of the G protein betagamma subunit to multiple regions of G protein-gated inward-rectifying K+ channels . FEBS Letters . 405 . 3 . 291–8 . April 1997 . 9108307 . 10.1016/S0014-5793(97)00197-X . 44072628 . 1997FEBSL.405..291H .
5. He C, Yan X, Zhang H, Mirshahi T, Jin T, Huang A, Logothetis DE . Identification of critical residues controlling G protein-gated inwardly rectifying K(+) channel activity through interactions with the beta gamma subunits of G proteins . The Journal of Biological Chemistry . 277 . 8 . 6088–96 . February 2002 . 11741896 . 10.1074/jbc.M104851200 . free .