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. 1999 Jul;77(1):248–257. doi: 10.1016/S0006-3495(99)76886-4

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

D Kerschensteiner 1, M Stocker 1
PMCID: PMC1300326  PMID: 10388754

Abstract

Modulatory alpha-subunits of Kv 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.

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Selected References

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