The voltage-sensing domain of a phosphatase gates the pore of a potassium channel

Authors

Cristina Arrigoni, Università degli Studi di Milano
Indra Schroeder, Technische Universität Darmstadt
Giulia Romani, Università degli Studi di Milano
James L. Van Etten, University of Nebraska-LincolnFollow
Gerhard Thiel, Technische Universität DarmstadtFollow
Anna Moroni, Università degli Studi di MilanoFollow

Document Type

Article

Date of this Version

2-2013

Citation

J. Gen. Physiol. Vol. 141 No. 3 389–395 www.jgp.org/cgi/doi/10.1085/jgp.201210940

Comments

© 2013 Arrigoni et al. Used by permission.

Abstract

The modular architecture of voltage-gated K⁺ (Kv) channels suggests that they resulted from the fusion of a voltage-sensing domain (VSD) to a pore module. Here, we show that the VSD of Ciona intestinalis phosphatase (Ci-VSP) fused to the viral channel Kcv creates Kv_Synth1, a functional voltage-gated, outwardly rectifying K⁺ channel. Kv_Synth1 displays the summed features of its individual components: pore properties of Kcv (selectivity and filter gating) and voltage dependence of Ci-VSP (V1/2 = +56 mV; z of approx. 1), including the depolarizationinduced mode shift. The degree of outward rectification of the channel is critically dependent on the length of the linker more than on its amino acid composition. This highlights a mechanistic role of the linker in transmitting the movement of the sensor to the pore and shows that electromechanical coupling can occur without coevolution of the two domains.