Fig. 4.

Accumulation of AChRs in and removal of AChRs from pre-existing laminin-induced clusters in MuSK^−/− muscle cells expressing MuSK/WT or MuSK/KA-2. (A) Labeling scheme of myotubes expressing MuSK/WT or MuSK/KA-2. Cells were labeled with Alexa 488-conjugated α-BGT and relabeled with Alexa 594-conjugated α-BGT after 4, 8 and 16 h. (B) MuSK^−/− myotubes expressing MuSK wild-type (WT) or MuSK/KA-2 were cultured on laminin. Representative images of clusters are shown. Scale bar, 10 μm. (C) Quantification of mean fluorescence intensities for AChR removal (Alexa 488-labeled receptors) and AChR accumulation (Alexa 594-labeled receptors) is shown. AChR densities are similar in MuSK/WT and MuSK/KA-2 expressing cells. n > 22 (from two independent experiments); error bars, S.E.M.