CrkL is associated with WASP and syk.

(A-D) Aliquots of platelets were treated with collagen 50 μg/mL or buffer for 5 minutes and then were lysed in detergent buffer, as described in “Materials and methods.” CrkL was purified from the soluble extracts by immunoprecipitation (IP), and the denatured samples were divided into 4 equal aliquots. The immunizing peptide (30 μg/mL) was added during precipitation, as indicated. Replicate samples (with or without collagen treatment and with or without the immunizing peptide) were separated by 7.5% to 15% SDS-PAGE, transferred to nitrocellulose membrane, and immunoblotted with either 4G10 total phosphotyrosine antibody (A), anti-CrkL (B, lower panel), anti-syk (B, upper panel) anti-c-Cbl (C), or anti-WASP (D).