Tomogram sections of WPBs containing ILVs along with structural models. (A-C) Tomogram section with structural model consisting of WPB limiting model (green), ILV membrane (blue-green), VWF tubules (yellow), and ILV internal content (red). (A) Inset shows tomogram cross-section at the location of the red line. (B) WPB from an HHMEC with an ILV in the left side of the granule. The ILV contains internal content similar to cytoplasmic granules, as shown in supplemental Figure 4. (C) WPB in a HUVEC with a kink in the middle where tubules have disrupted paracrystalline order. The ILV contains densities similar in size to cytosolic densities visible throughout the tomogram section. Scale bars, 200 nm.