title: Type V secretion: mechanism(s) of autotransport through the bacterial outer membrane.
abstract: Autotransport in Gram-negative bacteria denotes the ability of surface-localized proteins to cross the outer membrane (OM) autonomously. Autotransporters perform this task with the help of a β-barrel transmembrane domain localized in the OM. Different classes of autotransporters have been investigated in detail in recent years; classical monomeric but also trimeric autotransporters comprise many important bacterial virulence factors. So do the two-partner secretion systems, which are a special case as the transported protein resides on a different polypeptide chain than the transporter. Despite the great interest in these proteins, the exact mechanism of the transport process remains elusive. Moreover, different periplasmic and OM factors have been identified that play a role in the translocation, making the term 'autotransport' debatable. In this review, we compile the wealth of details known on the mechanism of single autotransporters from different classes and organisms, and put them into a bigger perspective. We also discuss recently discovered or rediscovered classes of autotransporters.
authors.affiliation: Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen,  Germany.
authors.forename: Jack C
authors.initials: JC
authors.lastname: Leo
authors.forename: Iwan
authors.initials: I
authors.lastname: Grin
authors.forename: Dirk
authors.initials: D
authors.lastname: Linke
mesh_terms: D018829:Adhesins, Bacterial / Q000737:chemistry; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry; D058947:Bacterial Secretion Systems; D002462:Cell Membrane / Q000737:chemistry*; D006090:Gram-Negative Bacteria / Q000737:chemistry* / Q000502:physiology; D008958:Models, Molecular; D019897:Periplasm / Q000737:chemistry; D017510:Protein Folding; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D037521:Virulence Factors / Q000737:chemistry
chemical_list: D018829:Adhesins, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D058947:Bacterial Secretion Systems; D037521:Virulence Factors