MiRP1 Background Information Voltage-gated K+ channels in the plasma membrane control the repolarization and the frequency of action potentials in neurons, muscles, and other excitable cells. KCNE1 and KCNE2 (also known as MiRP1) are two single transmembrane domain b subunits of the delayed rectifier potassium channel IKr. In cardiac tissue, MiRP1 assembles with HERG, the pore-forming a subunit of IKr. In the brain, MiRP1 associates with KCNQ2 and accelerates the dissociation of KCNQ2 from the KCNQ2-KCNQ3 complex. MiRP1 also regulates the current amplitude and gating properties of the KCNQ1 K+ channel, and may assemble with KCNQ1 in the stomach to aid in K+ recycling, which is necessary for gastric acid secretion. The gene encoding human MiRP1 maps to chromosome 21q22.12. Missense mutations in the gene for MiRP1 result in congenital long QT syndrome and drug-induced cardiac arrhythmia.
