Figure 10.

Role of LAP protein family members Lano and Scribble on AChR aggregation. a, RT-PCR data from C2C12 myoblasts and myotubes incubated with agrin or brain. Note that Scribble and Lano, but not Densin-180, are expressed in C2C12 cells. b, Expression profiling by quantitative RT-PCR demonstrated more Scribble and Lano expression in myotubes than in myoblasts. MB, Myoblast; MT, myotubes. c, Western blot of coimmunoprecipitation studies. Note that precipitation of Lano or Scribble resulted in coprecipitation of MuSK. Band intensities reflect a weak interaction between MuSK and Lano or Scribble. d, e, Scribble-specific shRNA was transiently transfected into primary skeletal muscle cells. After differentiation to myotubes, the cells were treated with nerve-derived agrin. Length and surface area of AChR aggregates were plotted against their numbers. Note that a higher number of AChR aggregates with decreased surface areas were detected if Lano was knocked down. f, g, The fluorescence intensities of AChR aggregates analyzed (d, e) were presented as graphs. h–k, Same data shown for nerve-derived AChR aggregates on primary skeletal myotubes transfected with Scribble-specific shRNA (d–g) is presented for primary skeletal muscle cells transfected with Lano-specific shRNA. l, Graph summarizes the mean fluorescence intensity of AChR aggregates shown in f, g, j, and k. m, Primary skeletal muscle cells were transiently transfected with Lano- or Scribble-specific shRNAs, differentiated to myotubes, and identified by their GFP expression. Mean fluorescence intensities of nerve-independent AChR microclusters were determined and depicted as graph. Student's t test, *p < 1.6 × 10⁻⁵, **p < 1.6 × 10⁻¹².