Kooger R Szwedziak P Böck D Pilhofer M 2018 The need for bacteria to interact with their environment has driven the evolution of elaborate secretion systems. By virtue of their function, secretion systems are macromolecular complexes associated with the cell envelope and therefore inherently difficult to study by conventional structural biology techniques. Cryo-electron microscopy (cryoEM) has become an invaluable technique to study large membrane-embedded complexes and led to major advances in the mechanistic understanding of secretion systems. CryoEM comprises of two main modalities, namely single particle analysis and tomography. Here, we review how detailed structures retrieved by single particle analysis combine elegantly with tomography experiments in which the secretion systems are observed in their native cellular context. https://sonar.ch/global/documents/127636 eng info:eu-repo/semantics/altIdentifier/doi/10.1016/j.sbi.2018.08.007 info:eu-repo/semantics/altIdentifier/pmid/30223223 Current opinion in structural biology. - 2018 Bacterial Secretion Systems Cryoelectron Microscopy Macromolecular Substances Membrane Transport Proteins Models, Biological CryoEM of bacterial secretion systems. http://purl.org/coar/resource_type/c_6501