Native ClC-1 channels localize to the sarcolemma in FDB fibers from adult mice. (A) Immunofluorescence of native ClC-1 channels (left) and DHPRs (middle) in a representative FDB fiber from an adult mouse. The absence of ClC-1 and DHPR colocalization is highlighted by merging the two images (right). (B) The fluorescence intensity profile (top) from a confocal image of a representative FDB fiber from an adult mouse (bottom), showing regular periodicity of both ClC-1 (green) and DHPR (red) fluorescence signals. (C) Expanded view of the fluorescence intensity profile in the boxed region shown in B emphasizes that although the ClC-1 and DHPR signals share a similar regular periodicity, they are 90° out of phase. (D) The average (±SEM) results of fast-Fourier transformation analyses of fluorescence profiles from 26 experiments reveal that the ClC-1 and DHPR signals peak with a periodicity of 1 and 2 µm.