FIG. 1.

Identification of novel Cripto binding proteins. 293T cells were transfected with empty vector or Cripto-Flag, subjected to immunoprecipitation on anti-Flag beads, and then eluted with Flag peptide. Cripto-associated proteins were separated by SDS-PAGE and then either silver stained (A) or immunoblotted to nitrocellulose and probed with anti-GRP78 or anti-Cripto antibodies (C) as described in Materials and Methods. Bands a and b in panel A were excised and subjected to mass spectrometric analysis as described in Materials and Methods. Mass fingerprint data corresponding to band a identified as GRP78 are shown in panel B. IB, immunoblot; IP, immunoprecipitate; −, absence of; +, presence of.