Role of the carboxy-terminal region of the outer membrane protein AatA in the export of dispersin from enteroaggregative Escherichia coli

Iwashita, Mayumi; Nishi, Junichiro; Wakimoto, Naoko; Fujiyama, Rika; Yamamoto, Kimie; Tokuda, Koichi; Manago, Kunihiro; Kawano, Yoshifumi

doi:10.1111/j.1574-6968.2006.00123.x

Cited by 7 publications

(6 citation statements)

References 27 publications

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“…These equatorial domain mutations affected function without affecting stability or folding of TolC, as shown by cross-linking and immunoblotting. Evidence for the significance of the equatorial domain has also been found in the OMF AatA, where positions F381, L382 and L383 have been shown as essential for Aap secretion ( Iwashita et al, 2006 ). These positions mapped to the equatorial domain as based on the homology model of AatA ( Nishi et al, 2003 ).…”

Section: Functional and Biophysical Evidence Supporting Different Modmentioning

confidence: 93%

Architecture and roles of periplasmic adaptor proteins in tripartite eï¬„ux assemblies

2015

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Recent years have seen major advances in the structural understanding of the different components of tripartite eﬄux assemblies, which encompass the multidrug eﬄux (MDR) pumps and type I secretion systems. The majority of these investigations have focused on the role played by the inner membrane transporters and the outer membrane factor (OMF), leaving the third component of the system – the Periplasmic Adaptor Proteins (PAPs) – relatively understudied. Here we review the current state of knowledge of these versatile proteins which, far from being passive linkers between the OMF and the transporter, emerge as active architects of tripartite assemblies, and play diverse roles in the transport process. Recognition between the PAPs and OMFs is essential for pump assembly and function, and targeting this interaction may provide a novel avenue for combating multidrug resistance. With the recent advances elucidating the drug eﬄux and energetics of the tripartite assemblies, the understanding of the interaction between the OMFs and PAPs is the last piece remaining in the complete structure of the tripartite pump assembly puzzle.

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Section: Functional and Biophysical Evidence Supporting Different Modmentioning

confidence: 93%

Architecture and roles of periplasmic adaptor proteins in tripartite eï¬„ux assemblies

2015

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“…It is highly likely that AatA and TolC share a common ancestry and similar three-dimensional structures. We demonstrated that the three nonpolar amino acid residues 381 to 383 in the carboxy terminus of AatA are important for Aap secretion activity (12), as the nonpolar amino acid residue 412 (leucine) at the carboxy terminus of TolC is required to express its activity (43). Thus, AatA was found to be a homolog of TolC in EAEC 042.…”

mentioning

confidence: 85%

“…Aap secretion was evaluated as previously described (12,24,33). In brief, strains were grown overnight in high-glucose DMEM.…”

Section: Construction Of a Deletion Mutation At Amino Acid Residue 41mentioning

confidence: 99%

The Escherichia coli Efflux Pump TolC Promotes Aggregation of Enteroaggregative E. coli 042

et al. 2008

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Enteroaggregative Escherichia coli (EAEC) is an emerging enteric pathogen in both developing and industrialized countries. EAEC is defined as a diarrheal pathogen based on its characteristic aggregative adherence to HEp-2 cells in culture and its biofilm formation on the intestinal mucosa. We have reported that the novel protein AatA, which is encoded on the EAEC virulence plasmid pAA2, localizes to the outer membrane and facilitates export of the dispersin Aap across the outer membrane. Because AatA is an E. coli efflux pump TolC homolog, we investigated the role of TolC in the virulence of EAEC. No difference in Aap secretion was observed between the wild type and its tolC mutant (042tolC). However, characteristic aggregation in high-glucose Dulbecco's minimal essential medium for the wild type was diminished for 042tolC. In a microtiter plate assay, there were significantly more planktonic cells for 042tolC than for the wild type, while there were significantly fewer spontaneously precipitated cells on the substratum for 042tolC than for the wild type. In a HEp-2 cell adherence test, 042tolC showed less aggregative adherence than did the wild type. The strong aggregation and aggregative adherence were restored in the complement strain with tolC. In a transwell assay, planktonic cells of 042tolC decreased when cocultured with the wild type or the complement, while precipitated cells of 042tolC increased when cocultured with them. These results suggest that TolC promotes the aggregation and adhesion of EAEC 042 by secreting an assumed humoral factor.

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“… 651 Similarly, residues located at the base of carboxy-terminal elongation in the equatorial domain of AatA, homologous to E. coli TolC in enteroaggregative Escherichia coli , are required for the export of its substrate, Aap. 654 Finally, the inability for TolC to form a functional complex with CusAB and to confer resistance to copper and silver ions in vivo was also suggested to be caused by the seemingly different equatorial domains of CusC and TolC. 648 In VceC, part of the loop is not visible in the crystallographic structure probably because of its great flexibility.…”

Section: Outer Membrane Factors (Omfs): Tolc and Othersmentioning

confidence: 99%

“…As will be discussed in more detail below, proposed models of assembly between TolC and AcrA show that this loop is involved in the recruitment and interaction of the OMF porin with its PAP. , The importance of the equatorial domain has been shown by loss-of-function mutants of TolC. − It was shown that TolC requires a leucine residue at position 412, located in an equatorial domain that protrudes from the main body of TolC into the periplasm, to be functional . Similarly, residues located at the base of carboxy-terminal elongation in the equatorial domain of AatA, homologous to E. coli TolC in enteroaggregative Escherichia coli , are required for the export of its substrate, Aap . Finally, the inability for TolC to form a functional complex with CusAB and to confer resistance to copper and silver ions in vivo was also suggested to be caused by the seemingly different equatorial domains of CusC and TolC .…”

Section: Outer Membrane Factors (Omfs): Tolc and Othersmentioning

confidence: 99%

Structure, Assembly, and Function of Tripartite Efflux and Type 1 Secretion Systems in Gram-Negative Bacteria

et al. 2021

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Tripartite efflux pumps and the related type 1 secretion systems (T1SSs) in Gram-negative organisms are diverse in function, energization, and structural organization. They form continuous conduits spanning both the inner and the outer membrane and are composed of three principal components—the energized inner membrane transporters (belonging to ABC, RND, and MFS families), the outer membrane factor channel-like proteins, and linking the two, the periplasmic adaptor proteins (PAPs), also known as the membrane fusion proteins (MFPs). In this review we summarize the recent advances in understanding of structural biology, function, and regulation of these systems, highlighting the previously undescribed role of PAPs in providing a common architectural scaffold across diverse families of transporters. Despite being built from a limited number of basic structural domains, these complexes present a staggering variety of architectures. While key insights have been derived from the RND transporter systems, a closer inspection of the operation and structural organization of different tripartite systems reveals unexpected analogies between them, including those formed around MFS- and ATP-driven transporters, suggesting that they operate around basic common principles. Based on that we are proposing a new integrated model of PAP-mediated communication within the conformational cycling of tripartite systems, which could be expanded to other types of assemblies.

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Role of the carboxy-terminal region of the outer membrane protein AatA in the export of dispersin from enteroaggregative Escherichia coli

Cited by 7 publications

References 27 publications

Architecture and roles of periplasmic adaptor proteins in tripartite eï¬„ux assemblies

Architecture and roles of periplasmic adaptor proteins in tripartite eï¬„ux assemblies

The Escherichia coli Efflux Pump TolC Promotes Aggregation of Enteroaggregative E. coli 042

Structure, Assembly, and Function of Tripartite Efflux and Type 1 Secretion Systems in Gram-Negative Bacteria

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