The DTS and OCS are highly intertwined membrane complexes. Dual axis tilt series were generated from chemically fixed platelets as described in “Tomography and data analysis.” (A-B) Series of tomographic slices through the OCS membrane complex. Small membrane continuities (blue arrowheads) connect individual OCS vacuoles and are continuous with the cell surface. DTS membranes (white arrowheads) are closely positioned to the OCS neck regions. (C) OCS and DTS membranes were manually traced to generate a 3D representation of the membrane complexes. (D-E) Three-dimensional reconstructions of the OCS (dark blue) and DTS (yellow). (F) Reconstructed model showing the highly intertwined nature of the membrane complexes. (An animated model of the OCS and DTS is included as supplemental Video 3.) (A-B) Bars represent 50 nm. (C) Bars represent 200 nm.