Fig. 8.

Grb2 is required for the formation of complex AChR clusters. Different siRNAs were evaluated for their ability to deplete Grb2 expression by using RT-qPCR (A) and immunoblotting (B). Error bars represent s.d. (C) Knockdown of Grb2 affects the formation of large AChR clusters with complex topology. Laminin-cultured C2C12 myotubes were transfected with siRNAs against the indicated genes and stained with α-bungarotoxin to visualize AChRs. Scale bar: 50 μm. (D) Quantification of the number of complex clusters per visual field in control and Grb2-depleted myotubes. The percentage of clusters (normalized to control) is shown as an average from three independent experiments; the number of clusters was n=343 for negative control, n=76 for siRNA 1, n=49 for siRNA 2 and n=110 for siRNA 3. Two-tailed Student t-test; mean±s.e.m.; *P<0.05, **P<0.01, ***P<0.001; ns, not significant; neg. contr., negative control, non-targeting siRNA; MuSK siRNA, positive control.