The Role of Nonprotein Domains in the Function and Synthese

Due to its central role in the generation af the nervous impulse, the sodium channel of nerve and muscle has been the most extensively studied of all voltage-gated ion channels. While most of the early work focused on functional properties using biiophysical techniques, more recent attention has been given to the molecular structure of the channel with the ultimate goal of understanding the mechanicms of ian transport, ion selectivity, and voltagedependent gating. Naturally, there are other interests in sodium channel biology besides the problem of molecular mechanism. The complete elucidation of the biosynthetic history of the channel, from the regulation of its gene expression to its posttranslational processing and intracellular targeting, is essential to understand how channel numbers, subtypes, and the nonhomogeneous distribution of these molecules are maintained by the cell. In addition, knowledge of the biosynthetic events that occur as the channel matures may eventually help ta define which parts of the molecule are required for proper operation.