Cloning provides evidence for a family of inward rectifier and G‐protein coupled K+ channels in the brain

FEBS Letters

Lazdunski, Michel¹  Guillemare, Eric¹  Lesage, Florian¹  Duprat, Fabrice¹  Coppola, Thierry¹  Fink, Michel¹  Hugnot, Jean-Philippe¹ 

[1] Institut de Pharmacologie Moléculaire et Cellulaire, CNRS, 660 route des Lucioles, Sophia Antipolis, 06560 Valbonne, France

关键词: Inward rectifier K+ channel;    G protein effector;    Xenopus oocyte;   

DOI  :  10.1016/0014-5793(94)01007-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

MbIRK3, mbGIRK2 and mbGIRK3 K⁺ channels cDNAs have been cloned from adult mouse brain. These eDNAs encode polypeptides of 445, 414 and 376 amino acids, respectively, which display the hallmarks of inward rectifier K⁺ channels, i.e. two hydrophobic membrane-spanning domains M1 and M2 and a pore-forming domain H5. MbIRK3 shows around 65% amino acid identity with IRK1 and rbIRK2 and only 50% with ROMK1 and GIRK1. On the other hand, mbGIRK2 and mbGIRK3 are more similar to GIRK1 (60%) than to ROMK1 and IRK1 (50%). Northern blot analysis reveals that these three novel clones are mainly expressed in the brain. Xenopus oocytes injected with mbIRK3 and mbGIRK2 cRNAs display inward rectifier K⁺-selective currents very similar to IRK1 and GIRK1, respectively. As expected from the sequence homology, mbGIRK2 cRNA directs the expression of G-protein coupled inward rectifyer K⁺ channels which has been observed through their functional coupling with co-expressed δ-opioid receptors. These results provide the first evidence that the GIRK family, as the IRK family, is composed of multiple genes with members specifically expressed in the nervous system.

【 授权许可】

Unknown