Figure 3.

Agrin does not induce receptor recycling at AChR clusters on cultured myotubes. C2C12 and primary muscle cells were cultured on dishes focally impregnated with agrin expressed by COS-1 cells and were labeled with a saturating dose of BTX-biotin followed by a saturating dose of green streptavidin. 6 hours later, myotubes were bathed with (red) streptavidin-Alexa594 to label recycled AChRs and with BTX-Alexa430 to label newly synthesized AChRs. Note that few or no recycled receptors were present at agrin induced clusters. Bars, 10 µm