Fig. 2.

MuRF1 interacts with AChR on endo/lysosomal carriers. a BGT-biotin or solvent was injected into gastrocnemius muscles. Five hours later, muscles were collected and lysates prepared. From these, BGT-biotin-bound AChR and its interaction partners were affinity-precipitated with neutravidin beads. Panels show Western blot bands of lysates and affinity precipitates (AP) upon exposure to antibodies against AChRα, MuRF1, α-actinin (positive control), or β1-adrenergic receptor (β1-AR, negative control), as indicated. b–c Tibialis anterior muscles were transfected with MuRF1-GFP. Ten days later, muscles were injected with the fluorescent AChR marker, BGT-AF647, and then monitored with in vivo confocal imaging. After acquisition, all images were electronically contrasted to highlight the weak endocytic AChR signals. In overlay pictures, AChR and GFP signals appear red and green, respectively. Colocalization of AChR and GFP signals is depicted in yellow. b Median filtered single optical planes of fluorescence signals. Scale bar represents 20 μm. c Panels depict high power views of the boxed regions shown in b. White and red arrowheads indicate colocalizing and partially overlapping signals, respectively, in endocytic carriers