The VgrG Proteins Are "à la Carte" Delivery Systems for Bacterial Type VI Effectors
File(s)
Published version
Author(s)
Hachani, A
Allsopp, LP
Oduko, Y
Filloux, A
Type
Journal Article
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.
Date Issued
2014-05-02
Date Acceptance
2014-05-02
Citation
Journal of Biological Chemistry, 2014, 289 (25), pp.17872-17884
ISSN
1083-351X
Publisher
American Society for Biochemistry and Molecular Biology
Start Page
17872
End Page
17884
Journal / Book Title
Journal of Biological Chemistry
Volume
289
Issue
25
Copyright Statement
This article is available under a CC BY license.
License URL
Sponsor
Biotechnology and Biological Sciences Research Council (BBSRC)
Medical Research Council (MRC)
Grant Number
BB/I019871/1
MR/K001930/1
Subjects
Science & Technology
Life Sciences & Biomedicine
Biochemistry & Molecular Biology
BIOCHEMISTRY & MOLECULAR BIOLOGY
GRAM-NEGATIVE BACTERIA
PSEUDOMONAS-AERUGINOSA
SECRETION-SYSTEM
VIBRIO-CHOLERAE
OPPORTUNISTIC PATHOGEN
CRYSTAL-STRUCTURE
TARGET-CELLS
GENE FAMILY
TAIL
TOXIN
Bacterial Cell Envelope
Bacterial Genetics
Bacterial Toxin
Microbiology
Protein Translocation
Pseudomonas aeruginosa (P. aeruginosa)
Type VI Secretion System
VgrG
Bacterial Proteins
Bacterial Secretion Systems
Bacterial Toxins
Carrier Proteins
Pseudomonas aeruginosa
06 Biological Sciences
11 Medical And Health Sciences
03 Chemical Sciences
Publication Status
Published