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Appendages of the cyanobacterial cell.

Schuergers N, Wilde A - Life (Basel) (2015)

Bottom Line: However, only for a very few cyanobacteria structure and function of these appendages have been analyzed.PCC 6803 and analyze the distribution of type IV pili associated genes in other cyanobacteria.Further, we discuss the role of the RNA-chaperone Hfq in pilus function and the presence of genes for the chaperone-usher pathway of pilus assembly in cyanobacteria.

View Article: PubMed Central - PubMed

Affiliation: University of Freiburg, Institute of Biology III, Schänzlestr. 1, 79104 Freiburg, Germany. Nils.Schuergers@biologie.uni-freiburg.de.

ABSTRACT
Extracellular non-flagellar appendages, called pili or fimbriae, are widespread in gram-negative bacteria. They are involved in many different functions, including motility, adhesion, biofilm formation, and uptake of DNA. Sequencing data for a large number of cyanobacterial genomes revealed that most of them contain genes for pili synthesis. However, only for a very few cyanobacteria structure and function of these appendages have been analyzed. Here, we review the structure and function of type IV pili in Synechocystis sp. PCC 6803 and analyze the distribution of type IV pili associated genes in other cyanobacteria. Further, we discuss the role of the RNA-chaperone Hfq in pilus function and the presence of genes for the chaperone-usher pathway of pilus assembly in cyanobacteria.

No MeSH data available.


Related in: MedlinePlus

(a) Model of type IV pili and their assembly machineries in cyanobacteria. Most cyanobacteria harbor more than one PilA homolog. Their specific functions are unknown so far. (b) Synteny of Synechocystis 6803 gene clusters encoding type IV pili proteins in comparison with similar genes clusters of diverse cyanobacteria. Color-coding of open reading frames refers to the schematic view in (a).
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life-05-00700-f001: (a) Model of type IV pili and their assembly machineries in cyanobacteria. Most cyanobacteria harbor more than one PilA homolog. Their specific functions are unknown so far. (b) Synteny of Synechocystis 6803 gene clusters encoding type IV pili proteins in comparison with similar genes clusters of diverse cyanobacteria. Color-coding of open reading frames refers to the schematic view in (a).

Mentions: Type IV pili are 6–8 nm in diameter and several μm in length and can form bundles. They are essential for many different processes like biofilm formation, aggregation, twitching motility and virulence [12,13]. Genes that encode core components of the type IV pilus show high sequence similarity, even if they originate from evolutionary divergent bacterial groups [14]. Type IV pili are assembled by a complex machinery at the inner membrane [15]. The main structural component of the pilus (PilA) is produced as a precursor. PilD removes the N-terminal leader sequence and methylates the protein. The assembly of the pilus requires a large ATP driven complex. This machinery is also essential for the reversibility of assembly and retraction of the pilus, a major feature of type IV pili. The PilB ATPase is required for pilus assembly, whereas PilT energizes depolymerisation of the pilus. Both ATPases are located at the base of the pilus and most probably interact with PilC, which is embedded in the inner membrane. PilQ forms the pore for the pilus to cross the outer membrane (Figure 1a). According to differences in their subunits, assembly system, and gene organization, two type IV pili subfamilies can be distinguished. Type IVa pili are widely distributed and highly conserved among many bacterial phyla and typically associated with twitching motility. The more heterogeneous type IVb pili are only found in a small subset of genera and often lack an ATPase for pilus retraction [14].


Appendages of the cyanobacterial cell.

Schuergers N, Wilde A - Life (Basel) (2015)

(a) Model of type IV pili and their assembly machineries in cyanobacteria. Most cyanobacteria harbor more than one PilA homolog. Their specific functions are unknown so far. (b) Synteny of Synechocystis 6803 gene clusters encoding type IV pili proteins in comparison with similar genes clusters of diverse cyanobacteria. Color-coding of open reading frames refers to the schematic view in (a).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4390875&req=5

life-05-00700-f001: (a) Model of type IV pili and their assembly machineries in cyanobacteria. Most cyanobacteria harbor more than one PilA homolog. Their specific functions are unknown so far. (b) Synteny of Synechocystis 6803 gene clusters encoding type IV pili proteins in comparison with similar genes clusters of diverse cyanobacteria. Color-coding of open reading frames refers to the schematic view in (a).
Mentions: Type IV pili are 6–8 nm in diameter and several μm in length and can form bundles. They are essential for many different processes like biofilm formation, aggregation, twitching motility and virulence [12,13]. Genes that encode core components of the type IV pilus show high sequence similarity, even if they originate from evolutionary divergent bacterial groups [14]. Type IV pili are assembled by a complex machinery at the inner membrane [15]. The main structural component of the pilus (PilA) is produced as a precursor. PilD removes the N-terminal leader sequence and methylates the protein. The assembly of the pilus requires a large ATP driven complex. This machinery is also essential for the reversibility of assembly and retraction of the pilus, a major feature of type IV pili. The PilB ATPase is required for pilus assembly, whereas PilT energizes depolymerisation of the pilus. Both ATPases are located at the base of the pilus and most probably interact with PilC, which is embedded in the inner membrane. PilQ forms the pore for the pilus to cross the outer membrane (Figure 1a). According to differences in their subunits, assembly system, and gene organization, two type IV pili subfamilies can be distinguished. Type IVa pili are widely distributed and highly conserved among many bacterial phyla and typically associated with twitching motility. The more heterogeneous type IVb pili are only found in a small subset of genera and often lack an ATPase for pilus retraction [14].

Bottom Line: However, only for a very few cyanobacteria structure and function of these appendages have been analyzed.PCC 6803 and analyze the distribution of type IV pili associated genes in other cyanobacteria.Further, we discuss the role of the RNA-chaperone Hfq in pilus function and the presence of genes for the chaperone-usher pathway of pilus assembly in cyanobacteria.

View Article: PubMed Central - PubMed

Affiliation: University of Freiburg, Institute of Biology III, Schänzlestr. 1, 79104 Freiburg, Germany. Nils.Schuergers@biologie.uni-freiburg.de.

ABSTRACT
Extracellular non-flagellar appendages, called pili or fimbriae, are widespread in gram-negative bacteria. They are involved in many different functions, including motility, adhesion, biofilm formation, and uptake of DNA. Sequencing data for a large number of cyanobacterial genomes revealed that most of them contain genes for pili synthesis. However, only for a very few cyanobacteria structure and function of these appendages have been analyzed. Here, we review the structure and function of type IV pili in Synechocystis sp. PCC 6803 and analyze the distribution of type IV pili associated genes in other cyanobacteria. Further, we discuss the role of the RNA-chaperone Hfq in pilus function and the presence of genes for the chaperone-usher pathway of pilus assembly in cyanobacteria.

No MeSH data available.


Related in: MedlinePlus