Biogenesis of dense and α-granules is not regulated by PKD2 activity. Washed platelets from WT or PKD2^SSAA/SSAA mice were examined by transmission electron microscopy, and the number of dense granules (black arrows) and α-granules (white arrows) was quantified as described in “Electron microscopy.” (A) Images of platelets from WT (left panel) or PKD2^SSAA/SSAA (right panel) mice are representative of 3 independent experiments. Original magnification was 19 000×, and the bar represents 500 nm. (B) Dense and α-granules were counted per fields of view (25-30 fields of view per section, 3 sections per preparation on average) and are shown as means ± SEM, n = 3.