KCNE1 and familial long QT syndrome: However, co-transfection of KCNQ1 and E1(RSKK) can produce slow-activated current, indicating that the sequence RSKK play a crucial role in gating modulation of IKs. It has been reported by other group that KCNE1 mutations (R67C, R67H, K70M, and K70N), which are associated with LQTS, could reduce IKs current [49].