A Landmark Protein Essential for Establishing and Perpetuating the Polarity of a Bacterial Cell

Lam, Hubert; Schofield, Whitman B.; Jacobs‐Wagner, Christine

doi:10.1016/j.cell.2005.12.040

Cited by 167 publications

(204 citation statements)

References 32 publications

(40 reference statements)

Supporting

Mentioning

200

Contrasting

Order By: Relevance

“…Our data argue that the presence and proper localization of PflI are important for positioning the flagellum at the correct pole. It is known that mutations in genes involved in multiple aspects of cell polarity or polar morphogenesis can result in flagellar placement defects (1,20,21,27,47,49). Unlike some of these genes with pleiotropic functions, pflI does not affect cell division or stalk biogenesis, as judged by the normal cell and stalk morphology of ⌬pflI and pflI-overexpressing cells (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…5B). Using a fluorescence microscopy technique that visualizes flagella (27), we found cells with bipolar PflI-GFP fluorescence as well as a flagellum emerging from the stalked pole (see Fig. S2D in the supplemental material).…”

Section: Resultsmentioning

confidence: 99%

“…Flagellar staining was performed as previously described (27). Briefly, cells from a mid-log-phase cell culture grown in PYE were fixed with a solution of 2.5% paraformaldehyde and 30 mM NaPO 4 (pH 7.5) for 30 min at room temperature.…”

Section: Methodsmentioning

confidence: 99%

“…The sessile stalked cells then begin expressing flagellar genes in a stepwise, hierarchical manner, and a new flagellum is formed at the pole opposite the stalk (28,35,52). Division yields a flagellated swarmer progeny for dispersal and a sessile stalked progeny for local colonization.Defects in flagellar placement have been observed in several C. crescentus mutants, but the mutations lie in genes that have pleiotropic functions in cell polarization and polar morphogenesis (1,20,21,27,47,49). In this study, we identify CC_2060, renamed pflI (the polar-flagellum-linked gene), as one of the genes specifically associated with flagellar positioning.…”

mentioning

confidence: 97%

“…Defects in flagellar placement have been observed in several C. crescentus mutants, but the mutations lie in genes that have pleiotropic functions in cell polarization and polar morphogenesis (1,20,21,27,47,49). In this study, we identify CC_2060, renamed pflI (the polar-flagellum-linked gene), as one of the genes specifically associated with flagellar positioning.…”

mentioning

confidence: 97%

See 4 more Smart Citations

PflI, a Protein Involved in Flagellar Positioning in Caulobacter crescentus

Obuchowski

Jacobs‐Wagner

2008

J Bacteriol

Self Cite

View full text Add to dashboard Cite

The bacterial flagellum is important for motility and adaptation to environmental niches. The sequence of events required for the synthesis of the flagellar apparatus has been extensively studied, yet the events that dictate where the flagellum is placed at the onset of flagellar biosynthesis remain largely unknown. We addressed this question for alphaproteobacteria by using the polarly flagellated alphaproteobacterium Caulobacter crescentus as an experimental model system. To identify candidates for a role in flagellar placement, we searched all available alphaproteobacterial genomes for genes of unknown function that cluster with early flagellar genes and that are present in polarly flagellated alphaproteobacteria while being absent in alphaproteobacteria with other flagellation patterns. From this in silico screen, we identified pflI. Loss of PflI function in C. crescentus results in an abnormally high frequency of cells with a randomly placed flagellum, while other aspects of cell polarization remain normal. In a wild-type background, a fusion of green fluorescent protein (GFP) and PflI localizes to the pole where the flagellum develops. This polar localization is independent of the flagellar protein FliF, whose oligomerization into the MS ring is thought to define the site of flagellar synthesis, suggesting that PflI acts before or independently of this event. Overproduction of PflI-GFP often leads to ectopic localization at the wrong, stalked pole. This is accompanied by a high frequency of flagellum formation at this ectopic site, suggesting that the location of PflI is a sufficient marker for a site for flagellar assembly.Flagellar arrangement has long been used as a defining characteristic in bacterial taxonomy. Bacteria can have flagella emerging from a specific site, such as the cell pole, or from seemingly random positions along the cell body (as in peritrichously flagellated bacteria). Differences in flagellar distribution can be important for how various species adapt to specific environments. While the biosynthesis of the flagellum and the temporal regulation of its assembly have been extensively studied (5, 32), we know little about what controls the cellular position of flagellar assembly. The distribution of flagella in peritrichous bacteria may be random and stochastically driven, but spatial mechanisms must exist in polarly flagellated bacteria to ensure that flagellar assembly takes place at the right location.It has been shown that in several polarly flagellated species of gammaproteobacteria, the flhF gene product is necessary for restricting the flagellum to a polar position (38, 41). flhF encodes a GTP-binding protein homologous to components of the signal recognition particle (SRP) pathway; in its absence, Pseudomonas putida and Pseudomonas aeruginosa have reduced motility and randomly placed flagella on the cell surface (25,38,41). Surprisingly, flhF homologs are also found in species with multiple, randomly placed flagella, indicating that FlhF is not a defining component of polarly f...

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 97%

mentioning

confidence: 97%

See 3 more Smart Citations

PflI, a Protein Involved in Flagellar Positioning in Caulobacter crescentus

Obuchowski

Jacobs‐Wagner

2008

J Bacteriol

Self Cite

View full text Add to dashboard Cite

show abstract

The domain organization of the bacterial intermediate filament‐like protein crescentin is important for assembly and function

2011

View full text Add to dashboard Cite

Crescentin is a bacterial filament-forming protein that exhibits domain organization features found in metazoan intermediate filament (IF) proteins. Structure-function studies of eukaryotic IFs have been hindered by a lack of simple genetic systems and easily quantifiable phenotypes. Here we exploit the characteristic localization of the crescentin structure along the inner curvature of Caulobacter crescentus cells and the loss of cell curvature associated with impaired crescentin function to analyze the importance of the domain organization of crescentin. By combining biochemistry and ultrastructural analysis in vitro with cellular localization and functional studies, we show that crescentin requires its distinctive domain organization, and furthermore that different structural elements have distinct structural and functional contributions. The head domain can be functionally subdivided into two subdomains; the first (amino-terminal) is required for function but not assembly, while the second is necessary for structure assembly. The rod domain is similarly required for structure assembly, and the linker L1 appears important to prevent runaway assembly into nonfunctional aggregates. The data also suggest that the stutter and the tail domain have critical functional roles in stabilizing crescentin structures against disassembly by monovalent cations in the cytoplasm. This study suggests that the IF-like behavior of crescentin is a consequence of its domain organization, implying that the IF protein layout is an adaptable cytoskeletal motif, much like the actin and tubulin folds, that is broadly exploited for various functions throughout life from bacteria to humans. © 2011 Wiley-Liss, Inc.

show abstract

Posttranslational oxidative modification of (R)‐2‐(2,4‐dichlorophenoxy)propionate/α‐ketoglutarate‐dependent dioxygenases (RdpA) leads to improved degradation of 2,4‐dichlorophenoxyacetate (2,4‐D)

Leibeling

Maess

Centler

et al. 2013

Engineering in Life Sciences

View full text Add to dashboard Cite

Microbial activities and the versatility gained through adaptation to xenobiotic compounds are the main biological forces to counteract environmental pollution.The current results present a new adaptive mechanism that is mediated through posttranslational modifications. Strains of Delftia acidovorans incapable of growing autochthonously on 2,4-dichlorophenoxyacetate (2,4-D) were cultivated in a chemostat on 2,4-D in the presence of (R)-2-(2,4-dichlorophenoxy)propionate. Long-term cultivation led to enhanced 2,4-D degradation, as demonstrated by improved values of the Michaelis-Menten constant K m for 2,4-D and the catalytic efficiency k cat /K m of the initial degradative key enzyme (R)-2-(2,4-dichlorophenoxy)propionate/ α-ketoglutarate-dependent dioxygenases (RdpA). Analyses of the rdpA gene did not reveal any mutations, indicating a nongenetic mechanism of adaptation. 2-DE of enzyme preparations, however, showed a series of RdpA forms varying in their pI. During adaptation increased numbers of RdpA variants were observed. Subsequent immunoassays of the RdpA variants showed a specific reaction with 2,4-dinitrophenylhydrazine (DNPH), characteristic of carbonylation modifications. Together these results indicate that posttranslational carbonylation modified the substrate specificity of RdpA. A model was implemented explaining the segregation of clones with improved degradative activity within the chemostat. The process described is capable of quickly responding to environmental conditions by reversibly adapting the degradative potential to various phenoxyalkanoate herbicides.Keywords: 2,4-Dichlorophenoxyacetate (2,4-D) / (R)-2-(2,4-Dichlorophenoxy)propionate / α-ketoglutarate-dependent dioxygenases (RdpA) / Individual-based modeling / Posttranslational carbonylationAdditional supporting information may be found in the online version of this article at the publisher's web-site

show abstract

A Landmark Protein Essential for Establishing and Perpetuating the Polarity of a Bacterial Cell

Cited by 167 publications

References 32 publications

PflI, a Protein Involved in Flagellar Positioning in Caulobacter crescentus

PflI, a Protein Involved in Flagellar Positioning in Caulobacter crescentus

The domain organization of the bacterial intermediate filament‐like protein crescentin is important for assembly and function

Posttranslational oxidative modification of (R)‐2‐(2,4‐dichlorophenoxy)propionate/α‐ketoglutarate‐dependent dioxygenases (RdpA) leads to improved degradation of 2,4‐dichlorophenoxyacetate (2,4‐D)

Contact Info

Product

Resources

About