Atg7-deficient platelets showed modest defects in ex vivo platelet function assays. (A) Representative western blot analysis showing reduced Atg7 and depleted LC3II levels in platelets from Atg7^f/f;PF4-Cre/+ mice compared with platelets from Atg7^f/f mice. For each genotype, results from 2 different mice are shown. (B) Lumi-aggregometry measurements of platelets from Atg7^f/f (red traces) and Atg7^f/f;PF4-Cre/+ (blue traces) mice when stimulated with thrombin (upper) or collagen (lower). Different agonist concentrations were titrated. The images shown are representative of at least 3 independent experiments. (C) Total levels of PF4 (left), total [³H]-serotonin uptake (middle), and total β-hexosaminidase activity (right) in platelets purified from Atg7^f/f and Atg7^f/f;PF4-Cre/+ mice. Data represent an average of 21 measurements. *P < .05, **P < .001, Student t test. (D) EM images of platelets from Atg7^f/f (i-iii) and Atg7^f/f;PF4-Cre/+ (iv-vi) mice. Samples were prepared by the freeze substitution method. α, α granules; arrows, dense granules; arrowheads and inset, isolation membranes. Scale bars, 500 nm. The images shown are representative micrographs from 2 independent experiments.