FIG. 7.

pYELP inhibits cellular responses to Fgf8. (A) pYELP peptide inhibits Fgf8-induced activation of Rac1 and Cdc42, but not Ras. A suspension culture of wild-type MEFs was pretreated with either pYELP or YELP peptide mixed with the carrier peptide PEP-1, and then cells were stimulated with 10 ng of Fgf8/ml for 10 min. Cell lysates were prepared, and pulldown assays were performed. (B) pYELP peptide inhibits Fgf8-induced Erk1/2 activation. Peptide and Fgf8 treatment was done as described above. Cell lysates were analyzed by immunoblots for phospho-Erk. (C) CRKL is essential for anchorage-independent cell growth induced by Fgf8. Colony-forming assays were performed using MEFs as described in Materials and Methods. Photographs of the colonies are shown.