CBL is dephosphorylated by SHP-1 and not SHP-2.

CBL immunoprecipitated from COS7 cells transfected with plasmids encoding the expression of FcγRIIA, CBL, SYK, SHP-1, or SHP-2 followed by FcγRIIA stimulation. (A) CBL immunoprecipitated from transfected COS7 cells was resolved by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotted with antiphosphotyrosine-specific antibodies (upper panel) and anti-CBL antisera (lower panel). Plasmid transfection conditions are shown above lanes. Transfected COS7 cells were either not stimulated (NS) or stimulated with IgG-opsonized sRBCs for times indicated. VC indicates cell lysates prepared from empty vector–transfected COS7 cells. (B) Anti-CBL, anti–SHP-1, and –SHP-2 immunoblot analysis of lysates prepared from resting COS7 cells shown in panel A. Lane 1, no transfection; lane 2, empty vector–transfected cells (control); lane 3, CBL transfected in the absence of SHP-1 or SHP-2; lane 4, CBL cotransfected with SHP-1; lane 5, CBL cotransfected with SHP-2.