Dimerization of the <i>Agrobacterium tumefaciens</i> VirB4 ATPase and the effect of ATP‐binding cassette mutations on the assembly and function of the T‐DNA transporter

Dang, Tu; Zhou, Xue-Rong; Graf, Brenda; Christie, Peter J.

doi:10.1046/j.1365-2958.1999.01436.x

Cited by 88 publications

(76 citation statements)

References 76 publications

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“…Information about the VirB4 family of ATPases is emerging 67,68 . For A. tumefaciens VirB4, enzymatic activity is required for substrate export, and this ATPase also seems to function as a homomultimer in vivo.…”

Section: The Mpf Atpasesmentioning

confidence: 99%

“…For A. tumefaciens VirB4, enzymatic activity is required for substrate export, and this ATPase also seems to function as a homomultimer in vivo. VirB4 possesses two domains that embed into, or protrude across, the cytoplasmic membrane, possibly forming contacts with machine subunits across the inner membrane 68 . Recently, evidence was presented for an interaction between VirB4 and VirB11 (REF.…”

Section: The Mpf Atpasesmentioning

confidence: 99%

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The versatile bacterial type IV secretion systems

Cascales¹,

Christie²

2003

Nat Rev Microbiol

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600

559

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Bacteria use type IV secretion systems for two fundamental objectives related to pathogenesisgenetic exchange and the delivery of effector molecules to eukaryotic target cells. Whereas gene acquisition is an important adaptive mechanism that enables pathogens to cope with a changing environment during invasion of the host, interactions between effector and host molecules can suppress defence mechanisms, facilitate intracellular growth and even induce the synthesis of nutrients that are beneficial to bacterial colonization. Rapid progress has been made towards defining the structures and functions of type IV secretion machines, identifying the effector molecules, and elucidating the mechanisms by which the translocated effectors subvert eukaryotic cellular processes during infection. The year 2003 marks the fiftieth anniversary of the first description of a TYPE IV SECRETION (T4S)SYSTEM: the CONJUGATION apparatus of the F plasmid 1 . This is a dynamic bacterial surface organelle, the activities of which are now known to include the contact-dependent delivery of DNA to bacterial recipients and the assembly and retraction of a conjugal PILUS 2 . In the past decade, reports describing systems that are ancestrally related to the F-transfer system and other conjugation machines have emerged. Instead of mediating DNA transfer between bacteria, these systems deliver DNA or protein substrates, known as effectors, to eukaryotic target cells during infection [3][4][5] . More recently, several new T4S systems have been described that are also ancestrally related to the conjugation machines, but these systems mediate the exchange of DNA with the extracellular milieu [6][7][8] . Collectively, this diversity of function in the face of a common ancestry makes the T4S machines attractive subjects for comparative studies that explore the dynamics of organelle assembly and action. Additionally, from a medical perspective, it is of enormous interest to develop a detailed understanding of how the inter-kingdom transfer of type IV effector molecules contributes to pathogenesis. This review will summarize the recent advances in our knowledge of T4S, NIH Public Access Author ManuscriptNat Rev Microbiol. Author manuscript; available in PMC 2013 December 27. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscriptwith an emphasis on machine structure and function, and the activities of effectors after translocation into the eukaryotic host. The T4S familyThis fascinatingly versatile translocation family can be classified into three subfamilies, each of which contributes in unique ways to pathogenesis ( Fig. 1; Table 1). The largest subfamily, the conjugation systems, are found in most species of Gram-negative and Grampositive bacteria. These systems mediate DNA transfer both within and between phylogenetically diverse species, and some systems even deliver DNA to fungi, plants and human cells 2,9-13 . Conjugation is an important contributor to genome plasticity, and therefore bacterial fitness under changing en...

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Section: The Mpf Atpasesmentioning

confidence: 99%

Section: The Mpf Atpasesmentioning

confidence: 99%

The versatile bacterial type IV secretion systems

Cascales¹,

Christie²

2003

Nat Rev Microbiol

Self Cite

600

559

View full text Add to dashboard Cite

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“…Several observations have led to the view that VirB4 is deeply engaged into protein interactions with other Mpf/CP components that take place independently of a functional nucleotide binding/hydrolysis domain (NBD). First, amino acid substitution mutants in the NBD of VirB4 display a negative-dominant phenotype (Berger and Christie, 1993;Dang et al, 1999;Fullner et al, 1994;Rabel et al, 2003). Second, a VirB4-Gfp fusion protein (TrhC of plasmid R27 fused to Gfp) localizes at discrete sites of the cellular membrane, and this localization, although requiring the presence of several Mpf components, does not require a functional NBD (Gilmour et al, 2001;Gilmour and Taylor, 2004).…”

Section: Virb4: a Motor Of Secretion Embedded In The Heart Of The Secmentioning

confidence: 99%

“…Third, the presence of a subset of VirB proteins, including VirB4, enhances the frequency of plasmid uptake when these cells serve as recipients in conjugation experiments with A. tumefaciens (Bohne et al, 1998). This eVect requires the presence of the oligomeric form of VirB4 in recipients, whereas it is independent of a functional NBD (Dang et al, 1999). The conclusion is that VirB4 homomultimers are important structural components necessary for the assembly of a robust membrane-spanning channel structure that is potentially capable of transferring DNA bidirectionally.…”

Section: Virb4: a Motor Of Secretion Embedded In The Heart Of The Secmentioning

confidence: 99%

The mating pair formation system of conjugative plasmids—A versatile secretion machinery for transfer of proteins and DNA

Schröder

Lanka

2005

Plasmid

190

146

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The mating pair formation (Mpf) system functions as a secretion machinery for intercellular DNA transfer during bacterial conjugation. The components of the Mpf system, comprising a minimal set of 10 conserved proteins, form a membrane-spanning protein complex and a surface-exposed sex pilus, which both serve to establish intimate physical contacts with a recipient bacterium. To function as a DNA secretion apparatus the Mpf complex additionally requires the coupling protein (CP). The CP interacts with the DNA substrate and couples it to the secretion pore formed by the Mpf system. Mpf/CP conjugation systems belong to the family of type IV secretion systems (T4SS), which also includes DNA-uptake and -release systems, as well as eVector protein translocation systems of bacterial pathogens such as Agrobacterium tumefaciens (VirB/VirD4) and Helicobacter pylori (Cag). The increased eVorts to unravel the molecular mechanisms of type IV secretion have largely advanced our current understanding of the Mpf/CP system of bacterial conjugation systems. It has become apparent that proteins coupled to DNA rather than DNA itself are the actively transported substrates during bacterial conjugation. We here present a uniWed and updated view of the functioning and the molecular architecture of the Mpf/CP machinery. 

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“…Two proteins are extracellular and associated with or are part of a pilus system: VirB2 is the pilus subunit itself, while VirB5 is a minor component of the pilus (23,24). Finally, one ATPase and two ATP-binding proteins appear to power the entire machinery: VirB11, VirB4, and VirD4, respectively (25)(26)(27)(28). In H. pylori, homologs for most of these proteins are encoded by the Cag pathogenicity island and are termed HPXXXX (where XXXX denotes the ORF number as defined in Ref.…”

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confidence: 99%

Biochemical Characterization of Protein Complexes from the Helicobacter pylori Protein Interaction Map

Terradot

Durnell

et al. 2004

Molecular & Cellular Proteomics

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We have investigated a large set of interactions from the Helicobacter pylori protein interaction map previously identified by high-throughput yeast two-hybrid (htY2H)-based methods. This study had two aims: i) to validate htY2H as a source of protein-protein interaction complexes for high-throughput biochemical and structural studies of the H. pylori interactome; and ii) to validate biochemically interactions shown by htY2H to involve components of the H. pylori type IV secretion systems. Thus, 17 interactions involving 31 proteins and protein fragments were studied, and a general strategy was designed to produce protein-interacting partners for biochemical and structural characterization. We show that htY2H is a valid source of protein-protein complexes for high-throughput proteome-scale characterization of the H. pylori interactome, because 76% of the interactions tested were confirmed biochemically. Of the interactions involving type IV secretion proteins, three could be confirmed. One interaction is between two components of the type IV secretion apparatus, ComB10 and ComB4, which are VirB10 and VirB4 homologs, respectively. Another interaction is between a type IV component (HP0525, a VirB11 homolog) and a non-type IV secretion protein (HP01451), indicating that proteins other than the core VirB (1-11)-VirD4 proteins may play a role in type IV secretion. Finally, a third interaction was biochemically confirmed between CagA, a virulence factor secreted by the type IV secretion system encoded by the Cag pathogenicity island, and a non-type IV secretion protein, HP0496.

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Dimerization of the Agrobacterium tumefaciens VirB4 ATPase and the effect of ATP‐binding cassette mutations on the assembly and function of the T‐DNA transporter

Cited by 88 publications

References 76 publications

The versatile bacterial type IV secretion systems

The versatile bacterial type IV secretion systems

The mating pair formation system of conjugative plasmids—A versatile secretion machinery for transfer of proteins and DNA

Biochemical Characterization of Protein Complexes from the Helicobacter pylori Protein Interaction Map

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