SMOC1 deficiency decreases platelet function in murine platelets. (A) Expression of the premature (pre-SMOC1) and mature secreted (SMOC1) forms of SMOC1 in platelets from WT and SMOC1^+/− (+/−) littermates; n = 6 animals per group. *P < .05, **P < .01, Student t test. (B) Adherent and nonspread (inactive) platelets isolated from WT and SMOC1^+/− (+/−) mice after seeding onto collagen; n = 4 animals per group. Scale bars, 10 μm. **P < .01, Student t test. (C) Platelet-leukocyte aggregates (PLA) in isolated whole blood from WT and SMOC1^+/− (+/−) mice following treatment with solvent (Sol) or thrombin (Thr); n = 6 animals per group. **P < .01, 2-way ANOVA and Newman-Keuls test. (D) Thrombin (Thr)-induced platelet aggregation in washed platelets from WT and SMOC1^+/− (+/−) mice; n = animals 7 per group. **P < .01, 2-way ANOVA and Bonferroni test. (E) Thrombin-induced clot retraction using erythrocyte-spiked platelet-rich plasma from WT and SMOC1^+/− (+/−) mice; n = 6 animals per group. ***P < .001, Student t test.