Detection of state-dependent change of the stoichiometry of KCNQ1-KCNE1 complex by single molecule imaging

KCNQ 1是电压门控性钾通道的α亚基，是心律失常的致病基因。KCNQ 1和它的辅助亚基KCNE 1形成一个离子通道复合物，它调节心跳。为了确定该复合物的化学计量，我在这些亚基上连接了荧光标记，并使用全内反射显微镜计数单个KCNQ 1-KCNE 1复合物中每个亚基的数量。KCNE 1亚基的数目取决于KCNQ 1和KCNE 1亚基的相对表达密度。

KCNQ1, which is known as a causative gene of cardiac arrhythmia, is an alpha subunit of voltage-gated K^+channel. KCNQ1 and its auxiliary subunit KCNE1 form an ion channel complex, which regulates the heartbeat. To determine the stoichiometry of this complex, I attached fluorescent tags on these subunits, and counted the number of each subunit in a single KCNQ1-KCNE1 complex by using total internal reflection microscope. One complex contained 1-4 KCNE1 subunits, and the number of KCNE1 was dependent on the relative expression densities of KCNQ1 and KCNE1 subunits.