Structure of potassium channels.

Qie Kuang,Pasi Purhonen,Hans Hebert

doi:10.1007/s00018-015-1948-5

Abstract

Potassium channels ubiquitously exist in nearly all kingdoms of life and perform diverse but important functions. Since the first atomic structure of a prokaryotic potassium channel (KcsA, a channel from Streptomyces lividans) was determined, tremendous progress has been made in understanding the mechanism of potassium channels and channels conducting other ions. In this review, we discuss the structure of various kinds of potassium channels, including the potassium channel with the pore-forming domain only (KcsA), voltage-gated, inwardly rectifying, tandem pore domain, and ligand-gated ones. The general properties shared by all potassium channels are introduced first, followed by specific features in each class. Our purpose is to help readers to grasp the basic concepts, to be familiar with the property of the different domains, and to understand the structure and function of the potassium channels better.

Highlights

Potassium (K?) channels locate in cell membranes and control transportation of K? ions efflux from and influx into cells
Since the first atomic structure of a prokaryotic potassium channel (KcsA, a channel from Streptomyces lividans) was determined, tremendous progress has been made in understanding the mechanism of potassium channels and channels conducting other ions
Based on the structures from wild-type Kir3.2 with (PDB: 3SYA [89]) and without (PDB: 3SYO) PIP2, and R201A mutants with (PDB: 3SYQ [89]) or without (PDB: 3SYP [89]) PIP2, it was concluded that binding of PIP2 alone does not open the gates in the pore-forming domain or the G-loop in the cytosolic domain, whereas G proteins alone open the G-loop but not the intracellular gate

Summary

Introduction

Potassium (K?) channels locate in cell membranes and control transportation of K? ions efflux from and influx into cells. As the intracellular gate opens to a certain degree (the distance between two T112 residues on diagonally positioned inner helices [17 A ), the SF starts to change its conformation from the conductive (activated) state to the nonconductive (inactivated) state (Fig. 3a). The large empty space between the VSD and the pore-forming domain is occupied by lipids (PDB: 2R9R), which play important functional and structural roles for Kv channels [52, 53, 64].

Results

Conclusion