N-Terminal Arginines Modulate Plasma-Membrane Localization of Kv7.1/KCNE1 Channel Complexes

This figure schematically illustrates KCNE1 structure and mutants used in the present study. A, left, alignment of KCNE1 sequences from various mammalian species. Grey underlines conserved residues. Glycine at position 38 is not strongly conserved among species providing no first-glance evidence for evolutionary importance. A, right, schematic of KCNE1 at the membrane with the N-terminal part oriented towards the cell exterior and C-terminus towards the cytosol. B, schematic of KCNE1 N-terminal constructs and mutations created for the present study. Ten N-terminal amino-acids (AA) illustrate differences between KCNE1 constructs. Position 38 carries a glycine in the wild-type (common allele) and is associated with atrial fibrillation. Position 38 carries a serine in the prevalent single nucleotide polymorphism. One of the constructs contained an N-terminal truncation (‘Δ1-38’), another one (‘linker’) replaced position 38 by 5 alanines. Additionally, three positively-charged arginines at positions 32, 33 and 36 have been exchanged for alanines in order to probe the role of these AA in KCNE1 function.