Structure and function of the adhesive type <scp>IV</scp> pilus of <i><scp>S</scp>ulfolobus acidocaldarius</i>

Henche, Anna-Lena; Ghosh, Abhrajyoti; Xiong, Yong; Jeske, Torsten; Egelman, Edward H.; Albers, Sonja‐Verena

doi:10.1111/j.1462-2920.2012.02898.x

Cited by 71 publications

(88 citation statements)

References 68 publications

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“…ΔpilA [1][2][3][4][5][6] has a severe motility defect Considering the hypermotility phenotype observed in Sulfolobus acidocaldarius lacking pilus biosynthesis genes aapE, aapF or the major pilin gene, aapB (Henche et al, 2012) we stab-inoculated deletion mutants, lacking either single or multiple pilins, on motility plates and determined their motility phenotypes. Our results show that the deletion of a single H. volcanii pilA gene or two pilA genes does not significantly affect motility compared to that of the H53 parent strain (from hereon referred to as the wild-type) (Fig.…”

Section: Resultsmentioning

confidence: 99%

A conserved type IV pilin signal peptide H‐domain is critical for the post‐translational regulation of flagella‐dependent motility

Esquivel

Pohlschröder

2014

Molecular Microbiology

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SummaryIn many bacteria and archaea, type IV pili facilitate surface adhesion, the initial step in biofilm formation. Haloferax volcanii has a specific set of adhesion pilins (PilA1-A6) that, although diverse, contain an absolutely conserved signal peptide hydrophobic (H) domain. Data presented here demonstrate that these pilins (PilA1-A6) also play an important role in regulating flagella-dependent motility, which allows cells to rapidly transition between planktonic and sessile states. Cells lacking adhesion pilins exhibit a severe motility defect, however, expression of any one of the adhesion pilins in trans can rescue the motility and adhesion. Conversely, while deleting pilB3-C3, genes required for PilA pilus biosynthesis, results in cells lacking pili and having an adhesion defect, it does not affect motility, indicating that motility regulation requires the presence of pilins, but not assembled pili. Mutagenesis studies revealed that the pilin-dependent motility regulatory mechanism does not require the diverse C-terminal region of the PilA pilins but specifically involves the conserved H-domain. This novel post-translational regulatory mechanism, which employs components that promote biofilm formation to inhibit motility, can provide a rapid response to changing environmental conditions. A model for this regulatory mechanism, which may also be present in other prokaryotes, is discussed.

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Section: Resultsmentioning

confidence: 99%

A conserved type IV pilin signal peptide H‐domain is critical for the post‐translational regulation of flagella‐dependent motility

Esquivel

Pohlschröder

2014

Molecular Microbiology

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“…Therefore, it appears that the proteins encoded in the operon form a membrane-associated cell surface structure and may function as a receptor for SIRV2. Moreover, it was demonstrated recently that Sso2386 carries multiple transmembrane helices and that Sso2387 constitutes an ATPase associated with a type IV secretion system, and they were designated AapF and AapE, respectively (28). Further, homologs of both are essential for the formation of the adhesive type IV pilus of S. acidocaldarius (28).…”

Section: Sirv2 Entry In Sulfolobusmentioning

confidence: 99%

“…Moreover, it was demonstrated recently that Sso2386 carries multiple transmembrane helices and that Sso2387 constitutes an ATPase associated with a type IV secretion system, and they were designated AapF and AapE, respectively (28). Further, homologs of both are essential for the formation of the adhesive type IV pilus of S. acidocaldarius (28). The association with the cell membrane of proteins encoded by both gene clusters strongly indicates their involvement in the entry process of SIRV2.…”

Section: Sirv2 Entry In Sulfolobusmentioning

confidence: 99%

Unveiling Cell Surface and Type IV Secretion Proteins Responsible for Archaeal Rudivirus Entry

Deng

Bhoobalan-Chitty

et al. 2014

J Virol

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Sulfolobus mutants resistant to archaeal lytic virus Sulfolobus islandicus rod-shaped virus 2 (SIRV2) were isolated, and mutations were identified in two gene clusters, cluster sso3138 to sso3141 and cluster sso2386 and sso2387, encoding cell surface and type IV secretion proteins, respectively. The involvement of the mutations in the resistance was confirmed by genetic complementation. Blocking of virus entry into the mutants was demonstrated by the lack of early gene transcription, strongly supporting the idea of a role of the proteins in SIRV2 entry.T o date, relatively few archaeal viruses have been characterized, and most of those that have been characterized infect acidothermophilic members of the order Sulfolobales. Despite their limited number of around 50 species, they exhibit considerably greater morphological diversity than the more extensively characterized bacteriophages, about 95% of which show head-tail morphologies. Archaeal viruses, in contrast, exhibit fusiform shapes, often with one or two tails, bottle shapes, bearded-globular forms, and a wide variety of rod-like and filamentous morphotypes which often carry small terminal appendages (1-3). This morphological diversity suggests that the archaeal viruses may employ a variety of mechanisms to enter their hosts, but current insights into entry mechanisms are limited to an OppA transporter protein, Sso1273, possibly providing a receptor site for the Acidianus two-tailed virus (ATV) in Sulfolobus solfataricus P2 (4). And very recently, microscopic studies suggested that Sulfolobus islandicus rod-shaped virus 2 (SIRV2) enters the host cell by attaching and moving through a pilus-like filament; however, the nature of the structure and the identity of the involved proteins remain elusive (5).Sulfolobus solfataricus P2 is an acidothermophilic crenarchaeon that can host a wide range of archaeal viruses, many of which are propagated stably (1, 3, 6). Moreover, few of the viruses appear to induce cell lysis, possibly reflecting a need to minimize contact with the harsh hot acidic environment. However, recent studies have identified a few viruses that can enter a lytic phase, including the Sulfolobus turreted icosahedral virus (STIV), the two-tailed fusiform (ATV), and, more recently, the rudivirus SIRV2 (7-9).SIRV2 is classified in the family Rudiviridae together with other well-characterized viruses, including SIRV1 (10, 11), ARV1 (12) and SRV1, (13), all of which are rod shaped and lack an envelope, and their genomes consist of linear double-stranded DNA with covalently closed ends (10,14,15). In a recent microarray analysis of S. solfataricus infected with SIRV2, we demonstrated that the viral genes were activated at different times and that mainly stressresponse host genes and those implicated in vesicle formation were downregulated (16). The results also illustrated that SIRV2 infection at a multiplicity of infection (MOI) of 30 resulted in growth inhibition of S. solfataricus 5E6 (16). In the present experiment, the culture was infected at a lower...

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“…Two additional sets of adhesion pilins have been identified in the Sulfolobales, one of which was also involved in Sulfolobus acidocaldarius autoaggregation (32,33). Microcolony formation has been observed in many archaeal species, including S. acidocaldarius and Sulfolobus solfataricus (34,35).…”

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confidence: 99%

Novel Archaeal Adhesion Pilins with a Conserved N Terminus

Esquivel¹,

Xu²,

Pohlschröder³

2013

Journal of Bacteriology

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Type IV pili play important roles in a wide array of processes, including surface adhesion and twitching motility. Although archaeal genomes encode a diverse set of type IV pilus subunits, the functions for most remain unknown. We have now characterized six Haloferax volcanii pilins, PilA[1-6], each containing an identical 30-amino-acid N-terminal hydrophobic motif that is part of a larger highly conserved domain of unknown function (Duf1628). Deletion mutants lacking up to five of the six pilin genes display no significant adhesion defects; however, H. volcanii lacking all six pilins (⌬pilA[1-6]) does not adhere to glass or plastic. Consistent with these results, the expression of any one of these pilins in trans is sufficient to produce functional pili in the ⌬pilA[1-6] strain. PilA1His and PilA2His only partially rescue this phenotype, whereas ⌬pilA[1-6] strains expressing PilA3His or PilA4His adhere even more strongly than the parental strain. Most surprisingly, expressing either PilA5His or PilA6His in the ⌬pilA[1-6] strain results in microcolony formation. A hybrid protein in which the conserved N terminus of the mature PilA1His is replaced with the corresponding N domain of FlgA1 is processed by the prepilin peptidase, but it does not assemble functional pili, leading us to conclude that Duf1628 can be annotated as the N terminus of archaeal PilA adhesion pilins. Finally, the pilin prediction program, FlaFind, which was trained primarily on archaeal flagellin sequences, was successfully refined to more accurately predict pilins based on the in vivo verification of PilA[1-6].

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Structure and function of the adhesive type IV pilus of Sulfolobus acidocaldarius

Cited by 71 publications

References 68 publications

A conserved type IV pilin signal peptide H‐domain is critical for the post‐translational regulation of flagella‐dependent motility

A conserved type IV pilin signal peptide H‐domain is critical for the post‐translational regulation of flagella‐dependent motility

Unveiling Cell Surface and Type IV Secretion Proteins Responsible for Archaeal Rudivirus Entry

Novel Archaeal Adhesion Pilins with a Conserved N Terminus

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