Abstract
Store-operated Ca(2+) entry (SOCE) pathway plays important roles in many cellular processes, which is largely studied by using fluorescent Ca(2+) indicator, Fura-2. Extracellular Mn(2+) is able to cross the plasma membrane through SOCE and quenches the fluorescence signals from Fura-2. Thus, the fluorescence quenching rate by Mn(2+) composes a convenient assay to monitor the extent of SOCE. This chapter describes an experimental method of Mn(2+) quenching assay for both cultured esophageal epithelial and skeletal muscle cells. It also explains how to perform a quantitative analysis of graded SOCE.