Recent advances in the structural and molecular biology of type IV secretion systems

• Published in: Current opinion in structural biology 2014-08, Vol.27, p.16-23
• Main Authors: Trokter, Martina, Felisberto-Rodrigues, Catarina, Christie, Peter J, Waksman, Gabriel
• Format: Article
• Language: English
• Subjects: Adenosine Triphosphatases - metabolism; Bacterial Secretion Systems; Biological Transport; Cell Membrane - metabolism; Energy Metabolism; Fimbriae, Bacterial - metabolism; Humans
• ISSN: 0959-440X; 1879-033X
• DOI: 10.1016/j.sbi.2014.02.006

•We describe the first structure of a type IV secretion (T4S) system.•The previously reported core complex is mostly an outer membrane complex.•We describe the newly discovered inner membrane complex and the stalk.•We discuss proposed translocation mechanisms of T4S systems.•We discuss the regulation of pilus biogenesis and substrate transfer by T4S systems. Bacteria use type IV secretion (T4S) systems to deliver DNA and protein substrates to a diverse range of prokaryotic and eukaryotic target cells. T4S systems have great impact on human health, as they are a major source of antibiotic resistance spread among bacteria and are central to infection processes of many pathogens. Therefore, deciphering the structure and underlying translocation mechanism of T4S systems is crucial to facilitate development of new drugs. The last five years have witnessed considerable progress in unraveling the structure of T4S system subassemblies, notably that of the T4S system core complex, a large 1MegaDalton (MDa) structure embedded in the double membrane of Gram-negative bacteria and made of 3 of the 12 T4S system components. However, the recent determination of the structure of ∼3MDa assembly of 8 of these components has revolutionized our views of T4S system architecture and opened up new avenues of research, which are discussed in this review.