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The VgrG Proteins Are 'à la Carte' Delivery Systems for Bacterial Type VI Effectors
- Publication Year :
- 2014
- Publisher :
- American Society for Biochemistry and Molecular Biology, 2014.
-
Abstract
- The bacterial type VI secretion system (T6SS) is a supra-molecular complex akin to bacteriophage tails, with VgrG proteins acting as a puncturing device. The Pseudomonas aeruginosa H1-T6SS has been extensively characterized. It is involved in bacterial killing and in the delivery of three toxins, Tse1–3. Here, we demonstrate the independent contribution of the three H1-T6SS co-regulated vgrG genes, vgrG1abc, to bacterial killing. A putative toxin is encoded in the vicinity of each vgrG gene, supporting the concept of specific VgrG/toxin couples. In this respect, VgrG1c is involved in the delivery of an Rhs protein, RhsP1. The RhsP1 C terminus carries a toxic activity, from which the producing bacterium is protected by a cognate immunity. Similarly, VgrG1a-dependent toxicity is associated with the PA0093 gene encoding a two-domain protein with a putative toxin domain (Toxin_61) at the C terminus. Finally, VgrG1b-dependent killing is detectable upon complementation of a triple vgrG1abc mutant. The VgrG1b-dependent killing is mediated by PA0099, which presents the characteristics of the superfamily nuclease 2 toxin members. Overall, these data develop the concept that VgrGs are indispensable components for the specific delivery of effectors. Several additional vgrG genes are encoded on the P. aeruginosa genome and are not linked genetically to other T6SS genes. A closer inspection of these clusters reveals that they also encode putative toxins. Overall, these associations further support the notion of an original form of secretion system, in which VgrG acts as the carrier.
- Subjects :
- Biochemistry & Molecular Biology
Bacterial Toxins
VIBRIO-CHOLERAE
Bacterial Toxin
GENE FAMILY
TOXIN
Microbiology
OPPORTUNISTIC PATHOGEN
Bacterial Proteins
VgrG
Bacterial Genetics
CRYSTAL-STRUCTURE
Pseudomonas aeruginosa (P. aeruginosa)
GRAM-NEGATIVE BACTERIA
Bacterial Secretion Systems
Bacterial Cell Envelope
TAIL
Type VI Secretion System
Science & Technology
Protein Translocation
PSEUDOMONAS-AERUGINOSA
SECRETION-SYSTEM
11 Medical And Health Sciences
06 Biological Sciences
Pseudomonas aeruginosa
TARGET-CELLS
Carrier Proteins
03 Chemical Sciences
Life Sciences & Biomedicine
Subjects
Details
- Database :
- OpenAIRE
- Accession number :
- edsair.od......1032..12ede584605a748b0aa81b12327484b2