Fig. 8. C3G activation in response to reelin. (A) Reelin is present in the supernatant of 293T cells transfected with a reelin expression construct, but not in the supernatant of cells transfected with an empty vector (mock). (B) Immunoblot probed for tyrosine phosphorylated protein (pC3G) and reprobed for total C3G (lower panel) in lysates of E16.5 wild-type cortical neurons treated with supernatant of reelin-expressing or mock transfected 293T cells for 15 minutes and precipitated with anti-C3G antibody. Numbers below lanes indicate relative densitometry readings corrected for total C3G. (C) Immunoblot probed for Rap1 in lysate of neural precursor cells treated with reelin or control supernatant (mock) for 24 hours, then subjected to RalGDS-Rap1-binding domain affinity purification of GTP-loaded Rap1. Numbers below lanes indicate relative densitometry readings.