scholarly journals Atomic resolution structure of the cytoplasmic domain ofYersinia pestisYscU, a regulatory switch involved in type III secretion

2009 ◽  
Vol 18 (2) ◽  
pp. 467-474 ◽  
Author(s):  
George T. Lountos ◽  
Brian P. Austin ◽  
Sreedevi Nallamsetty ◽  
David S. Waugh
Keyword(s):  
Type Iii Secretion ◽  
Cytoplasmic Domain ◽  
Atomic Resolution ◽  
Type Iii ◽  
Resolution Structure

scholarly journals The Structure of an Injectisome Export Gate Demonstrates Conservation of Architecture in the Core Export Gate between Flagellar and Virulence Type III Secretion Systems

mBio ◽  
2019 ◽  
Vol 10 (3) ◽  
Author(s):  
Steven Johnson ◽  
Lucas Kuhlen ◽  
Justin C. Deme ◽  
Patrizia Abrusci ◽  
Susan M. Lea
Keyword(s):  
Type Iii Secretion ◽  
Complex Analysis ◽  
Secretion Systems ◽  
Core Complex ◽  
Type Iii ◽  
The Core ◽  
Cryo Electron Microscopy ◽  
Type Iii Secretion Systems ◽  
Equivalent Complex ◽  
Resolution Structure

ABSTRACT Export of proteins through type III secretion systems (T3SS) is critical for motility and virulence of many major bacterial pathogens. Proteins are exported through a genetically defined export gate complex consisting of three proteins. We have recently shown at 4.2 Å that the flagellar complex of these three putative membrane proteins (FliPQR in flagellar systems, SctRST in virulence systems) assembles into an extramembrane helical assembly that likely seeds correct assembly of the rod. Here we present the structure of an equivalent complex from the Shigella virulence system at 3.5 Å by cryo-electron microscopy. This higher-resolution structure yields a more precise description of the structure and confirms the prediction of structural conservation in this core complex. Analysis of particle heterogeneity also suggests how the SctS/FliQ subunits sequentially assemble in the complex. IMPORTANCE Although predicted on the basis of sequence conservation, the work presented here formally demonstrates that all classes of type III secretion systems, flagellar or virulence, share the same architecture at the level of the core structures. This absolute conservation of the unusual extramembrane structure of the core export gate complex now allows work to move to focusing on both mechanistic studies of type III but also on fundamental studies of how such a complex is assembled.

scholarly journals Structure and Interactions of the Cytoplasmic Domain of the Yersinia Type III Secretion Protein YscD

2012 ◽  
Vol 194 (21) ◽  
pp. 5949-5958 ◽  
Author(s):  
A. Gamez ◽  
R. Mukerjea ◽  
M. Alayyoubi ◽  
M. Ghassemian ◽  
P. Ghosh
Keyword(s):  
Type Iii Secretion ◽  
Cytoplasmic Domain ◽  
Type Iii

scholarly journals Structural Flexibility of the Cytoplasmic Domain of Flagellar Type III Secretion Protein FlhB is Important for the Function of the Protein

2012 ◽  
Vol 102 (3) ◽  
pp. 626a ◽  
Author(s):  
Vladimir A. Meshcheryakov ◽  
Clive S. Barker ◽  
Irina V. Meshcheryakova ◽  
Alla S. Kostyukova ◽  
Fadel A. Samatey
Keyword(s):  
Type Iii Secretion ◽  
Cytoplasmic Domain ◽  
Structural Flexibility ◽  
Type Iii

scholarly journals High-resolution structure of the Shigella type-III secretion needle by solid-state NMR and cryo-electron microscopy

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Jean-Philippe Demers ◽  
Birgit Habenstein ◽  
Antoine Loquet ◽  
Suresh Kumar Vasa ◽  
Karin Giller ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
High Resolution ◽  
Type Iii Secretion ◽  
Solid State Nmr ◽  
Type Iii ◽  
Cryo Electron Microscopy ◽  
High Resolution Structure ◽  
Resolution Structure

scholarly journals The cytoplasmic domain of MxiG interacts with MxiK and directs assembly of the sorting platform in the Shigella type III secretion system

2019 ◽  
Vol 294 (50) ◽  
pp. 19184-19196 ◽  
Author(s):  
Shoichi Tachiyama ◽  
Yunjie Chang ◽  
Meenakumari Muthuramalingam ◽  
Bo Hu ◽  
Michael L. Barta ◽  
...  
Keyword(s):  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Cytoplasmic Domain ◽  
Secretion System ◽  
Type Iii

scholarly journals The Structures of SctK and SctD from Pseudomonas aeruginosa Reveal the Interface of the Type III Secretion System Basal Body and Sorting Platform

2020 ◽  
Author(s):  
Meenakumari Muthuramalingam ◽  
Sean K. Whittier ◽  
Scott Lovell ◽  
Kevin P. Battaile ◽  
Shoichi Tachiyama ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Family Member ◽  
Basal Body ◽  
Type Iii Secretion ◽  
Cytoplasmic Domain ◽  
Protein Family ◽  
Protein Fold ◽  
Hybrid Analysis ◽  
Type Iii ◽  
Two Hybrid

AbstractMany Gram-negative bacterial pathogens use type III secretion systems (T3SS) to inject effector proteins into eukaryotic cells to subvert normal cellular functions. The T3SS apparatus (injectisome) shares a common overall architecture in all systems studied thus far, comprising three major components – the cytoplasmic sorting platform, the envelope-spanning basal body and the external needle with controlling tip complex. The sorting platform consists of an ATPase (SctN) connected to “pods” (SctQ) having six-fold symmetry via radial spokes (SctL). These pods interface with the 24-fold symmetric SctD inner membrane ring (IR) via an adaptor protein (SctK). Here we report the first high-resolution structure of a SctK protein family member, PscK from Pseudomonas aeruginosa, as well as the structure of its interacting partner, the cytoplasmic domain of PscD (SctD). The cytoplasmic domain of PscD forms a forkhead-associated (FHA) fold, like that of its homologues from other T3SS. PscK, on the other hand, forms a helix-rich structure that does not resemble any known protein fold. Based on these structural findings, we present the first model for an interaction between proteins from the sorting platform and the IR. We also test the importance of the PscD residues predicted to mediate this electrostatic interaction using a two-hybrid analysis. The functional need for Arg96 in vivo was then confirmed by monitoring secretion of the effector ExoU. These structures will contribute to the development of atomic-resolution models of the entire sorting platform and to our understanding of the mechanistic interface between the sorting platform and the basal body of the injectisome.HighlightsThe structures of Pseudomonas aeruginosa PscD (SctD) and PscK (SctK) were solvedThe interface between the T3SS basal body and sorting platform was modeledThe crystal structure of PscK is the first for any SctK family memberPscK represents a novel protein foldSite-directed mutagenesis supports a computational model of the PscD-PscK interfaceGraphical abstract.The first reported structure for a T3SS SctK protein family member was solved for PscK from Pseudomonas aeruginosa and this allowed for modeling of the interface between this sorting platform protein and the cytoplasmic domain of PscD (a SctD protein family member). This allowed for identification of amino acid residues that may play a role in the interaction between these proteins. The interface appears to be dominated by electrostatic interactions and mutagenesis confirmed the importance of key residues in driving their interaction based on two-hybrid analysis.

scholarly journals Nonameric structures of the cytoplasmic domain of FlhA and SctV in the context of the full-length protein

2020 ◽  
Author(s):  
Lucas Kuhlen ◽  
Steven Johnson ◽  
Jerry Y. Cao ◽  
Justin C. Deme ◽  
Susan M. Lea
Keyword(s):  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Cytoplasmic Domain ◽  
Secretion System ◽  
Full Length ◽  
Cytoplasmic Domains ◽  
Bacterial Flagella ◽  
Type Iii ◽  
Closed State ◽  
N Terminus

AbstractType three secretion is the mechanism of protein secretion found in bacterial flagella and injectisomes. At its centre is the export apparatus (EA), a complex of five membrane proteins through which secretion substrates pass the inner membrane. While the complex formed by four of the EA proteins has been well characterised structurally, little is known about the structure of the membrane domain of the largest subunit, FlhA in flagella, SctV in injectisomes. Furthermore, FlhA/SctV is most often studied as a monomer and only a single structure of an SctV homologue assembled into the biologically relevant nonameric ring is available. FlhA has been shown to bind to chaperone-substrate complexes in an open state, but in the assembled ring structure SctV is in a closed state. Here, we identify FlhA and SctV homologues that can be recombinantly produced in the oligomeric state and study them using cryo-electron microscopy. The structures of the cytoplasmic domains from both FlhA and SctV are in the open state and we observe a conserved interaction between a short stretch of residues at the N-terminus of the cytoplasmic domain, known as FlhAL/SctVL, with a groove on the adjacent protomer’s cytoplasmic domain, which stabilises the nonameric ring assembly. This represents the first structure of SctV in the open state, the first observation of the SctVL interaction with the adjacent protomer and confirms the importance of FlhAL for the stability of the FlhA nonameric ring.ImportanceBacterial flagella are assembled from proteins secreted through a type III secretion system. A related type III secretion system is found in injectisomes, molecular syringes that bridge three membranes to secrete proteins directly from the bacterial cytoplasm into eukaryotic host cells. The major protein of the export apparatus of type III secretion is made up of a membrane and a cytoplasmic domain, which in the flagellar system can adopt an open or a closed state, is known to form a nonameric ring in vivo. We produced the full-length proteins from both injectisome and flagellar systems in the assembled state. The structures of the cytoplasmic domains demonstrate the conserved principle of the N-terminus of one subunit binding the membrane proximal face of the adjacent subunit to stabilise the assembled ring. Our structure of the homologue from the injectisome also demonstrates that the open state of the cytoplasmic domain is not unique to flagella.

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