The outer-membrane protein MafA of Neisseria meningitidis constitutes a novel protein secretion pathway specific for the fratricide protein MafB

Arenas, J. (Universidad de Zaragoza) ; Catón, L. ; van den Hoeven, T. ; de Maat, V. ; Cruz Herrero, J. ; Tommassen, J.

Resumen: MafB proteins are toxins secreted by Neisseria spp. which are involved in interbacterial competition. Their secretion mechanism has so far not been elucidated. Each strain can produce several MafB variants. On the chromosome, the mafB genes are localized on genomic islands also containing mafA genes. MafA proteins have a role in virulence with reported activities in adhesion and transcytosis of pathogenic Neisseria, a priori unrelated to MafB activities. In this study, we investigated the possible involvement of MafA in the transport of MafB across the outer membrane of Neisseria meningitidis. In wild-type strains, proteolytic fragments of MafB proteins were detected in the extracellular medium. In the absence of MafA, secretion was abrogated, and, in the case of MafBI, full-length and truncated polypeptides were detected inside the cells and inside outer-membrane vesicles. MafBI secretion required its cognate MafA, whereas MafBIII could use any MafA. Heterologous expression in Escherichia coli showed that MafBIII is transported to a cell-surface-exposed, i.e. protease-accessible, location in a MafA-dependent way. MafA itself was found to be localized to the outer membrane, forming large oligomeric complexes. As homologs were found in diverse bacteria, the Maf system represents a new protein secretion system in Gram-negative bacteria.

Idioma: Inglés

DOI: 10.1080/21505594.2020.1851940

Año: 2020

Publicado en: Virulence 11, 1 (2020), 1701-1715
ISSN: 2150-5594

Factor impacto JCR: 5.882 (2020)

Categ. JCR: INFECTIOUS DISEASES rank: 12 / 92 = 0.13 (2020) - Q1 - T1
Categ. JCR: MICROBIOLOGY rank: 23 / 136 = 0.169 (2020) - Q1 - T1
Categ. JCR: IMMUNOLOGY rank: 44 / 162 = 0.272 (2020) - Q2 - T1

Factor impacto SCIMAGO: 1.927 - Immunology (Q1) - Infectious Diseases (Q1) - Parasitology (Q1) - Microbiology (medical) (Q1) - Microbiology (Q1)

Financiación: info:eu-repo/grantAgreement/ES/ISCIII-EDRF/PT17-0019

Tipo y forma: Artículo (Versión definitiva)

Área (Departamento): Área Sanidad Animal (Dpto. Patología Animal)