Salinas M, de Weille J, Guillemare E, Lazdunski M, Hugnot J P
Institut de Pharmacologie Moléculaire et Cellulaire, CNRS, 660 route des Lucioles, Sophia Antipolis, 06560 Valbonne, France.
J Biol Chem. 1997 Mar 28;272(13):8774-80. doi: 10.1074/jbc.272.13.8774.
The Kv8.1 subunit is unable to generate K+ channel activity in Xenopus oocytes or in COSm6 cells. The Kv8.1 subunit expressed at high levels acts as a specific suppressor of the activity of Kv2 and Kv3 channels in Xenopus oocytes (Hugnot, J. P., Salinas, M., Lesage, F., Guillemare, E., Weille, J., Heurteaux, C., Mattéi, M. G., and Lazdunski, M. (1996) EMBO J. 15, 3322-3331). At lower levels, Kv8.1 associates with Kv2.1 and Kv2.2 to form hybrid Kv8.1/Kv2 channels, which have new biophysical properties and more particularly modified properties of the inactivation process as compared with homopolymers of Kv2.1 or Kv2.2 channels. The same effects have been seen by coexpressing the Kv8.1 subunit and the Kv2.2 subunit in COSm6 cells. In these cells, Kv8.1 expressed alone remains in intracellular compartments, but it can reach the plasma membrane when it associates with Kv2.2, and it then also forms new types of Kv8.1/Kv2. 2 channels. Present results indicate that Kv8.1 when expressed at low concentrations acts as a modifier of Kv2.1 and Kv2.2 activity, while when expressed at high concentrations in oocytes it completely abolishes Kv2.1, Kv2.2, or Kv3.4 K+ channel activity. The S6 segment of Kv8.1 is atypical and contains the structural elements that modify inactivation of Kv2 channels.
Kv8.1亚基在非洲爪蟾卵母细胞或COS-7细胞中无法产生钾离子通道活性。高水平表达的Kv8.1亚基可作为非洲爪蟾卵母细胞中Kv2和Kv3通道活性的特异性抑制剂（于尼奥，J.P.，萨利纳斯，M.，勒萨热，F.，吉勒马尔，E.，韦勒，J.，厄尔托，C.，马泰，M.G.，拉兹敦斯基，M.（1996年）《欧洲分子生物学组织杂志》15，3322 - 3331）。在较低水平时，Kv8.1与Kv2.1和Kv2.2结合形成杂合的Kv8.1/Kv2通道，与Kv2.1或Kv2.2通道的同聚物相比，这些通道具有新的生物物理特性，尤其是失活过程的改变特性。在COS-7细胞中共表达Kv8.1亚基和Kv2.2亚基也观察到了相同的效应。在这些细胞中，单独表达的Kv8.1保留在细胞内区室中，但当它与Kv2.2结合时可到达质膜，然后也形成新型的Kv8.1/Kv2.2通道。目前的结果表明，低浓度表达时Kv8.1作为Kv2.1和Kv2.2活性的调节剂，而在卵母细胞中高浓度表达时它完全消除Kv2.1、Kv2.2或Kv3.4钾离子通道活性。Kv8.1的S6段是非典型的，包含改变Kv2通道失活的结构元件。
