ABSTRACT
The function of ion channels is essential for many cell processes. Functional studies of a particular type of ion channel in native cells are sometimes rather complicated because of the diversity of native channel types. Certain mammalian cell lines developed with very low expression of endogenous ion channels have been used as convenient heterologous expression systems for the functional study of particular ion channels. These systems provide machinery and pathways similar to those of native mammalian cells with normal ion channel expression levels. Furthermore, the heterologous expression approach together with in vitro (or site-directed) mutagenesis allows investigation into protein structure and function targeted to the specific area of interest in an ion channel. The aim of this chapter is to describe the technique of sitedirected mutagenesis and to illustrate how it is applied in functional studies of cloned ion channels heterologously expressed in mammalian cell lines.
