Andreas Diepold

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The assembly of the Yersinia enterocolitica type III secretion injectisome was investigated by grafting fluorescent proteins onto several components, YscC (outer-membrane (OM) ring), YscD (forms the inner-membrane (IM) ring together with YscJ), YscN (ATPase), and YscQ (putative C ring). The recombinant injectisomes were functional and appeared as(More)
Deglycosylation of misfolded proteins by the endoplasmic reticulum-associated degradation (ERAD) pathway is catalyzed by peptide:N-glycanases (PNGases) that are highly conserved among mammals and yeast. The catalytic mechanism of PNGases employs a catalytic triad consisting of Cys, His and Asp residues, which is shared by other enzyme families such as(More)
Injectisomes are multi-protein transmembrane machines allowing pathogenic bacteria to inject effector proteins into eukaryotic host cells, a process called type III secretion. Here we present the first three-dimensional structure of Yersinia enterocolitica and Shigella flexneri injectisomes in situ and the first structural analysis of the Yersinia(More)
YscV (FlhA in the flagellum) is an essential component of the inner membrane (IM) export apparatus of the type III secretion injectisome. It contains eight transmembrane helices and a large C-terminal cytosolic domain. YscV was expressed at a significantly higher level than the other export apparatus components YscR, YscS, YscT, and YscU, and YscV-EGFP(More)
The Type VI secretion system (T6SS) is a bacterial nanomachine that fires toxic proteins into target cells. Deployment of the T6SS represents an efficient and widespread means by which bacteria attack competitors or interact with host organisms and may be triggered by contact from an attacking neighbor cell as a defensive strategy. Here, we use the(More)
Many gram-negative pathogens employ a type III secretion injectisome to translocate effector proteins into eukaryotic host cells. While the structure of the distal "needle complex" is well documented, the composition and role of the functionally important cytosolic complex remain less well understood. Using functional fluorescent fusions, we found that the(More)
The flagellum and the injectisome are two of the most complex and fascinating bacterial nanomachines. At their core, they share a type III secretion system (T3SS), a transmembrane export complex that forms the extracellular appendages, the flagellar filament and the injectisome needle. Recent advances, combining structural biology, cryo-electron tomography,(More)
Many bacteria that live in contact with eukaryotic hosts, whether as symbionts or as pathogens, have evolved mechanisms that manipulate host cell behaviour to their benefit. One such mechanism, the type III secretion system, is employed by Gram-negative bacterial species to inject effector proteins into host cells. This function is reflected by the overall(More)
The assembly of the type III secretion injectisome culminates in the formation of the needle. In Yersinia, this step requires not only the needle subunit (YscF), but also the small components YscI, YscO, YscX and YscY. We found that these elements act after the completion of the transmembrane export apparatus. YscX and YscY co-purified with the export(More)
Bacterial type III secretion systems or injectisomes are multiprotein complexes directly transporting bacterial effector proteins into eukaryotic host cells. To investigate the distribution of injectisomes in the bacterium and the influence of activation of the system on that distribution, we combined in vivo fluorescent imaging and high-resolution in situ(More)