The macromolecular architecture of platelet-derived microparticles.

摘要: Platelets are essential for hemostasis and wound healing. They involved in fundamental processes of vascular biology such as angiogenesis, tissue regeneration, tumor metastasis. Upon activation, platelets shed small plasma membrane vesicles termed platelet-derived microparticles (PMPs). PMPs include functional cell adhesion machinery that comprises transmembrane receptors (most abundant the αIIbβ3 integrins), cytoskeletal systems a large variety adapter signaling molecules. Glanzmann thrombasthenia (GT) is condition characterized by deficient integrin heterodimer. Here, we use cryo-electron tomography (cryo-ET) to study structural organization (in both healthy GT patients), especially cytoskeleton receptor architecture. purified from patients show significantly altered organization, reduced number filaments present, compared control. Furthermore, our results incubating with manganese ions (Mn(2+)), presence fibrinogen, induces major conformational change receptors, whereas thrombin activation yields moderate response. These provide first insights into native molecular PMPs.