Figure 7. Ptpn6 contact with the actin-myosin cytoskeleton is mediated by Y208.

a) The structure of the Ptpn6 C-terminal SH2 domain bound to a phosphopeptide derived from the Natural Killer Group 2A (NKG2A) protein is displayed (PDB ID: 2YU7). The solvent accessible surface of the Ptpn6 SH2 domain (white) is shown overlaid on a ribbon diagram of the domain. The bound NKG2A phosphopeptide is shown in black with the phosphotyrosine residue indicated in stick representation. Tyrosine 208 is located at the C-terminal end of the BG loop. It is solvent accessible and does not contact the specificity-determining pocket (+3 pocket), nor the phosphotyrosine binding pocket. b) Coomassie staining for proteins associated with the wild-type and Y208N mutant Ptpn6 C-SH2 domains following immunoprecipitation from 10⁸ neutrophils. Representative data from two biologically independent experiments. Peptides isolated from gel slices in (A) and (B) are described in Supplementary Table 2. c) Immunoblot for Myosin-9 in 5 × 10⁶ neutrophils following immunoprecipitation with the biotinylated peptides corresponding to the wild-type and Y208N mutant Ptpn6 C-SH2 domain. Representative data from three biologically independent experiments. d) Isothermal titration calorimetry (ITC) analysis comparing the interaction of FcγR2b phosphopeptide with wild-type and Y208N mutant recombinant C-terminal SH2 domain. Representative data from two biologically independent experiments.