タンパク質・ペプチド: General secretion pathway protein GspD
キーワード
PROTEIN TRANSPORT
機能・相同性
機能・相同性情報
protein secretion by the type II secretion system / type II protein secretion system complex / cell outer membrane / membrane => GO:0016020 類似検索 - 分子機能
Type II secretion system protein GspD / GspD/PilQ family / Bacterial type II secretion system protein D signature. / Type II secretion system protein GspD, conserved site / NolW-like / Bacterial type II/III secretion system short domain / NolW-like superfamily / Type II/III secretion system / Bacterial type II and III secretion system protein 類似検索 - ドメイン・相同性
General secretion pathway protein GspD 類似検索 - 構成要素
Natural Sciences and Engineering Research Council (Canada)
カナダ
引用
ジャーナル: PLoS Pathog / 年: 2019 タイトル: Structure and assembly of pilotin-dependent and -independent secretins of the type II secretion system. 著者: S Peter Howard / Leandro F Estrozi / Quentin Bertrand / Carlos Contreras-Martel / Timothy Strozen / Viviana Job / Alexandre Martins / Daphna Fenel / Guy Schoehn / Andréa Dessen / 要旨: The type II secretion system (T2SS) is a cell envelope-spanning macromolecular complex that is prevalent in Gram-negative bacterial species. It serves as the predominant virulence mechanism of many ...The type II secretion system (T2SS) is a cell envelope-spanning macromolecular complex that is prevalent in Gram-negative bacterial species. It serves as the predominant virulence mechanism of many bacteria including those of the emerging human pathogens Vibrio vulnificus and Aeromonas hydrophila. The system is composed of a core set of highly conserved proteins that assemble an inner membrane platform, a periplasmic pseudopilus and an outer membrane complex termed the secretin. Localization and assembly of secretins in the outer membrane requires recognition of secretin monomers by two different partner systems: an inner membrane accessory complex or a highly sequence-diverse outer membrane lipoprotein, termed the pilotin. In this study, we addressed the question of differential secretin assembly mechanisms by using cryo-electron microscopy to determine the structures of the secretins from A. hydrophila (pilotin-independent ExeD) and V. vulnificus (pilotin-dependent EpsD). These structures, at approximately 3.5 Å resolution, reveal pentadecameric stoichiometries and C-terminal regions that carry a signature motif in the case of a pilotin-dependent assembly mechanism. We solved the crystal structure of the V. vulnificus EpsS pilotin and confirmed the importance of the signature motif for pilotin-dependent secretin assembly by performing modelling with the C-terminus of EpsD. We also show that secretin assembly is essential for membrane integrity and toxin secretion in V. vulnificus and establish that EpsD requires the coordinated activity of both the accessory complex EpsAB and the pilotin EpsS for full assembly and T2SS function. In contrast, mutation of the region of the S-domain that is normally the site of pilotin interactions has little effect on assembly or function of the ExeD secretin. Since secretins are essential outer membrane channels present in a variety of secretion systems, these results provide a structural and functional basis for understanding the key assembly steps for different members of this vast pore-forming family of proteins.