Identification of inner membrane translocase components of ToIC-mediated secretion in the cyanobacterium Synechocystis sp PCC 6803

• Type: Article in International Scientific Journal
• Date: 2018

Authors

Goncalves, CF (Author) Other; Pacheco, CC (Author) Other; Paula Tamagnini (Author) FCUP; Oliveira, P (Author) FCUP

Journal

Title: Environmental Microbiology

Vol. 20

Pages: 2354-2369

ISSN: 1462-2912

Publisher: Wiley-Blackwell

Indexing

ISI Web of Knowledge - 0 Citations

Scopus - 25 Citations

Other information

Authenticus ID: P-00P-HGM

DOI: 10.1111/1462-2920.14095

Abstract (EN): Cyanobacteria were the first organisms ever to perform oxygenic photosynthesis and still significantly contribute to primary production on a global scale. To assure the proper functioning of their primary metabolism and cell homeostasis, cyanobacteria must rely on efficient transport systems to cross their multilayered cell envelope. However, cyanobacterial secretion mechanisms remain largely unknown. Here, we report on the identification of 11 putative inner membrane translocase components of ToIC-mediated secretion in the unicellular cyanobacterium Synechocystis sp. PCC 6803. Gene-inactivation of each of the candidate genes followed by a comprehensive phenotypic characterization allowed to link specific protein components to the processes of protein export (as part of the type I secretion system) and drug efflux (part of the resistance-division-nodulation efflux pumps). In addition, mutants in genes sll0141, sll0180 and slr0369 exhibited alterations in pilin glycosylation, but pili structures could still be observed by transmission electron microscopy. By studying the release of outer membrane vesicles (OMVs), an alternative secretion route, on mutants with impaired secretory functions we suggest that the hyper-vesiculating phenotype of the ToIC-deficient mutant is related to cell envelope stress management. Altogether, these findings highlight how both classical (ToIC-mediated) and nonclassical (OMVs-mediated) secretion systems are crucial for cyanobacterial cell homeostasis.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 16