Deficiency of Src homology 2 domain–containing inositol 5-phosphatase 1 affects platelet responses and thrombus growth
J. Clin. Invest. Sonia Séverin, et al. 117:944 doi:10.1172/JCI29967 [Go to this article.]

Figure 4
SHIP1-deficient platelets do not interact closely with each other upon stimulation despite normal fibrinogen binding. (A) Electron micrographs showing morphological features of WT and SHIP1-deficient platelets upon 1 IU/ml thrombin stimulation for 1 minute. Original magnification, ×6,000; ×1800. G, α-granules; DB, dense bodies; OCS, open canalicular system. (B) The binding of labeled fibrinogen to WT and SHIP1-deficient mouse platelets activated by thrombin (0.1 to 1 IU/ml) or U46619 (0.1 μM and 0.5 μM) for 10 minutes was measured by flow cytometry. A representative example of 2 independent experiments is shown. R, resting. (C) WT and SHIP1-deficient mouse platelets were stimulated with increasing concentrations of thrombin (0.1 to 1 IU/ml) for 3 minutes. The phosphorylation of the β₃ integrin cytoplasmic domain was assessed in resting and thrombin-stimulated platelets by immunoblotting with anti–β₃ integrin [pY⁷⁷³] phosphospecific antibody. A representative example of 4 independent experiments is shown. The phosphorylation level was estimated by densitometry analysis of Western blots, and the results are means ± SEM (n = 4). *Significant difference (P < 0.05) versus WT, according to 1-tailed Student’s t test.