Heteromeric assembly of Kv2.1 with Kv9.3: Effect on the state dependence of inactivation

被引:62
作者
Kerschensteiner, D [1 ]
Stocker, M [1 ]
机构
[1] Max Planck Inst Expt Med, Abt Mol Biol Neuronaler Signale, D-37075 Gottingen, Germany
关键词
D O I
10.1016/S0006-3495(99)76886-4
中图分类号
Q6 [生物物理学];
学科分类号
071011 ;
摘要
Modulatory ar-subunits of Ky channels remain electrically silent after homomeric expression. Their interactions with Kv2 alpha-subunits via the amino-terminal domain promote the assembly of heteromeric functional channels. The kinetic features of these heteromers differ from those of Kv2 homomers, suggesting a distinct role in electrical signaling. This study investigates biophysical properties of channels emerging from the coexpression of Kv2.1 with the modulatory alpha-subunit Kv9.3. Changes relative to homomeric Kv2.1 concern activation, deactivation, inactivation, and recovery from inactivation. A detailed description of Kv2.1/Kv9.3 inactivation is presented. Kv2.1/Kv9.3 heteromers inactivate in a fast and complete fashion from intermediate closed states, but. in a slow and incomplete manner from open states. Intermediate closed states of channel gating can be approached through partial activation or deactivation, according to a proposed qualitative model. These transitions are rate-limiting for Kv2.1/Kv9.3 inactivation. Finally, based on the kinetic description, we propose a putative function for Kv2.1/Kv9.3 heteromers in rat heart.
引用
收藏
页码:248 / 257
页数:10
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