PPE and PE_PGRS proteins of Mycobacterium marinum are transported via the type VII secretion system ESX‐5

AM Abdallah, T Verboom… - Molecular …, 2009 - Wiley Online Library
AM Abdallah, T Verboom, EM Weerdenburg, NC Gey van Pittius, PW Mahasha, C Jiménez
Molecular microbiology, 2009Wiley Online Library
ESX‐5 is one of the five type VII secretion systems found in mycobacteria. These secretion
systems are also known as ESAT‐6‐like secretion systems. Here, we have determined the
secretome of ESX‐5 by a proteomic approach in two different strains of Mycobacterium
marinum. Comparison of the secretion profile of wild‐type strains and their ESX‐5 mutants
showed that a number of PE_PGRS and PPE‐MPTR proteins are dependent on ESX‐5 for
transport. The PE and PPE protein families are unique to mycobacteria, are highly expanded …
Summary
ESX‐5 is one of the five type VII secretion systems found in mycobacteria. These secretion systems are also known as ESAT‐6‐like secretion systems. Here, we have determined the secretome of ESX‐5 by a proteomic approach in two different strains of Mycobacterium marinum. Comparison of the secretion profile of wild‐type strains and their ESX‐5 mutants showed that a number of PE_PGRS and PPE‐MPTR proteins are dependent on ESX‐5 for transport. The PE and PPE protein families are unique to mycobacteria, are highly expanded in several pathogenic species, such as Mycobacterium tuberculosis and M. marinum, and certain family members are cell surface antigens associated with virulence. Using a monoclonal antibody directed against the PGRS domain we showed that nearly all PE_PGRS proteins that are recognized by this antibody are missing in the supernatant of ESX‐5 mutants. In addition to PE_PGRS and PPE proteins, the ESX‐5 secretion system is responsible for the secretion of a ESAT‐6‐like proteins. Together, these data show that ESX‐5 is probably a major secretion pathway for mycobacteria and that this system is responsible for the secretion of recently evolved PE_PGRS and PPE proteins.
Wiley Online Library