Thrombin stimulates the translocation of Btk to the membrane.

(A) Mouse megakaryocytes were stimulated by thrombin (THR) and analyzed for expression of PLCγ2 and Btk as described in Figure 2. As labeled for each panel, Btk-stained megakaryocytes are unstimulated, THR-stimulated, wortmannin (wort)–treated, or XID megakaryocytes. Scale bar = 20 μm. Each image is representative of 8 megakaryocytes obtained from a minimum of 3 experiments on different animals. (B) The time course of Btk translocation was measured in control and XID megakaryocytes in response to THR (1 U/mL). The results are shown as distribution ratio (described in “Results” ).