Bender K, Wellner-Kienitz M C, Meyer T, Pott L
Institut für Physiologie, Abteilung Zelluläre Physiologie, Ruhr-Universität Bochum, Germany.
FEBS Lett. 1998 Nov 13;439(1-2):115-20. doi: 10.1016/s0014-5793(98)01350-7.
Muscarinic K+ channels (IK(ACh)) in native atrial myocytes are activated by betagamma subunits of pertussis toxin (Ptx)-sensitive heterotrimeric G proteins coupled to different receptors. betagamma subunits of Ptx-insensitive Gs, coupled to beta-adrenergic receptors, do not activate native IK(ACh). In atrial myocytes from adult rats transfected with rat brain beta1 subunit IK(ACh) can be activated by stimulation of beta-adrenergic receptors using isoprenaline. This effect is insensitive to Ptx. These findings demonstrate for the first time promiscuous (Ptx-insensitive) coupling of Gsbetagamma to GIRK channels in their native environment.
天然心房肌细胞中的毒蕈碱钾通道（IK(ACh)）由与不同受体偶联的百日咳毒素（Ptx）敏感异源三聚体G蛋白的βγ亚基激活。与β肾上腺素能受体偶联的Ptx不敏感Gs的βγ亚基不会激活天然IK(ACh)。在用大鼠脑β1亚基转染的成年大鼠心房肌细胞中，使用异丙肾上腺素刺激β肾上腺素能受体可激活IK(ACh)。这种效应对Ptx不敏感。这些发现首次证明了在其天然环境中Gsβγ与GIRK通道存在混杂（Ptx不敏感）偶联。
