Analysis of platelets from XLA patients.
Soluble extracts were prepared from patient A or a normal control (3 × 106 platelets/sample) and were then subjected to immunoblot analysis with (A) Btk or Tec antiserum. Collagen-stimulated tyrosine phosphorylation of Tec was analyzed as described in the legend to Figure 1D, and analyses are given for (B) patient A and (C) patient B. Tyrosine phosphorylation of (D) WASP or (E) Slp-76 in XLA platelets prior to or after 50 μg/mL collagen treatment for 5 minutes was examined by immunoblot analysis with 4G10 antibody following immunoprecipitation (anti-WASP or anti–Slp-76, patient B). The upper and lower portions of the membrane from the (E) anti–Slp76 immunoprecipitate was immunoblotted with anti-Fyb/Slp-130 or anti–Slp-76 as indicated. Tec and WASP phosphorylation studies were also performed using platelets from patients C-G, and similar results were obtained.
