Hoshi T, Zagotta W N, Aldrich R W
Department of Molecular and Cellular Physiology, Stanford University School of Medicine, California 94305.
Neuron. 1991 Oct;7(4):547-56. doi: 10.1016/0896-6273(91)90367-9.
Shaker potassium channels inactivate and recover from inactivation with multiple exponential components, suggesting the presence of multiple inactivation processes. We describe two different types of inactivation in Shaker potassium channels. N-type inactivation can occur as rapidly as a few milliseconds and has been shown to involve an intracellular region at the amino-terminal acting as a blocker of the pore. C-type inactivation is independent of voltage over a range of -25 to +50 mV. It does not require intact N-type inactivation, but is partially coupled to it. The kinetics of C-type inactivation are quite different for channels with different alternatively spliced carboxy-terminal regions. We have localized the differences in C-type inactivation between the ShB and ShA variants to a single amino acid in the sixth membrane-spanning region. N- and C-type inactivation occur by distinct molecular mechanisms.
震颤器钾通道通过多个指数成分失活并从失活状态恢复，这表明存在多个失活过程。我们描述了震颤器钾通道中两种不同类型的失活。N型失活能在几毫秒内迅速发生，并且已表明涉及氨基末端的一个细胞内区域作为孔道的阻滞剂。C型失活在-25至+50 mV的电压范围内与电压无关。它不需要完整的N型失活，但与之部分相关联。对于具有不同选择性剪接羧基末端区域的通道，C型失活的动力学有很大差异。我们已将ShB和ShA变体之间C型失活的差异定位到第六个跨膜区域的一个氨基酸上。N型和C型失活通过不同的分子机制发生。
