Structure and Function of Voltage-Dependent Ion Channel Regulatory β Subunits

• Published in: Biochemistry (Easton) Vol. 41; no. 9; pp. 2886 - 2894
• Main Authors: Hanlon, M. R, Wallace, B. A
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 05.03.2002
• Subjects: Calcium Channels - chemistry; Calcium Channels - physiology; Humans; Ion Channels - chemistry; Ion Channels - physiology; Models, Molecular; Potassium Channels - chemistry; Potassium Channels - physiology; Protein Conformation; Protein Subunits; Sodium Channels - chemistry; Sodium Channels - physiology
• ISSN: 0006-2960; 1520-4995
• DOI: 10.1021/bi0119565

Voltage-dependent K+, Ca2+, and Na+ channels play vital roles in basic physiological processes, including management of the action potential, signal transduction, and secretion. They share the common function of passively transporting ions across cell membranes; thus, it would not be surprising if they should exhibit similarities of both structure and mechanism. Indeed, the principal pore-forming (α) subunits of each show either exact or approximate 4-fold symmetry and share a similar transmembrane topology, and all are gated by changes in membrane potential. Furthermore, these channels all possess an auxiliary polypeptide, designated the β subunit, which plays an important role in their regulation. Despite considerable functional semblences and abilities to interact with structurally similar α subunits, however, there is considerable structural diversity among the β subunits. In this review, we discuss the similarities and differences in the structures and functions of the β subunits of the voltage-dependent K+, Ca2+, and Na+ channels.