Type VI secretion system MIX‐effectors carry both antibacterial and anti‐eukaryotic activities. (14th September 2017)

• Record Type: Journal Article
• Authors: Ray, Ann; Schwartz, Nika; de Souza Santos, Marcela; Zhang, Junmei; Orth, Kim; Salomon, Dor
• Is Part Of: EMBO reports. Volume 18:Number 11(2017)
• Page Start: 1978
• Page End: 1990
• Publication Date: 2017-09-14
• Subjects: bacterial competition -- CNF1 -- Vibrio -- virulence; Molecular biology -- Periodicals; Molecular Biology -- Periodicals; Molecular biology; Periodicals; 572.8
• DOI: 10.15252/embr.201744226
• Languages: English
• ISSNs: 1469-221X

Abstract

Abstract: Most type VI secretion systems (T6SSs) described to date are protein delivery apparatuses that mediate bactericidal activities. Several T6SSs were also reported to mediate virulence activities, although only few anti‐eukaryotic effectors have been described. Here, we identify three T6SSs in the marine bacterium Vibrio proteolyticus and show that T6SS1 mediates bactericidal activities under warm marine‐like conditions. Using comparative proteomics, we find nine potential T6SS1 effectors, five of which belong to the polymorphic MIX‐effector class. Remarkably, in addition to six predicted bactericidal effectors, the T6SS1 secretome includes three putative anti‐eukaryotic effectors. One of these is a MIX‐effector containing a cytotoxic necrotizing factor 1 domain. We demonstrate that T6SS1 can use this MIX‐effector to target phagocytic cells, resulting in morphological changes and actin cytoskeleton rearrangements. In conclusion, the V. proteolyticus T6SS1, a system homologous to one found in pathogenic vibrios, uses a suite of polymorphic effectors that target both bacteria and eukaryotic neighbors. Synopsis: Type VI secretion systems are protein delivery apparatuses that mediate predominately bactericidal activities. This study shows that a Vibrio T6SS utilizes a versatile repertoire of effectors to target both competing bacteria and neighbouring eukaryotic cells. The Vibrio proteolyticus T6SS1 mediates bacterial killing under warm marine‐like conditions. The Vibrio T6SS1 delivers a suite of effectors with predicted bactericidal and virulence activities. A CNF1‐containing Vibrio T6SS1 MIX‐effector induces actin rearrangements and morphological changes upon infection of macrophages. Abstract : Type VI secretion systems are protein delivery apparatuses that mediate predominately bactericidal activities. This study shows that a Vibrio T6SS utilizes a versatile repertoire of effectors to target both competing bacteria and neighbouring eukaryotic cells.