Format

Send to

Choose Destination
Mol Microbiol. 2012 Feb;83(3):654-64. doi: 10.1111/j.1365-2958.2011.07958.x. Epub 2012 Jan 11.

Polar assembly and scaffolding proteins of the virulence-associated ESX-1 secretory apparatus in mycobacteria.

Author information

1
Division of Genetics, Wadsworth Center, Center for Medical Science, New York State Department of Health, Albany, NY 12201, USA.

Abstract

The ESX-1 secretion system is required for pathogenicity of Mycobacterium tuberculosis (Mtb). Despite considerable research, little is known about the structural components of ESX-1, or how these proteins are assembled into the active secretion apparatus. Here, we exploit the functionally related ESX-1 apparatus of Mycobacterium smegmatis (Ms) to show that fluorescently tagged proteins required for ESX-1 activity consistently localize to the cell pole, identified by time-lapse fluoro-microscopy as the non-septal (old) pole. Deletions in Msesx1 prevented polar localization of tagged proteins, indicating the need for specific protein-protein interactions in polar trafficking. Remarkably, expression of the Mtbesx1 locus in Msesx1 mutants restored polar localization of tagged proteins, indicating establishment of the MtbESX-1 apparatus in M. smegmatis. This observation illustrates the cross-species conservation of protein interactions governing assembly of ESX-1, as well as polar localization. Importantly, we describe novel non-esx1-encoded proteins, which affect ESX-1 activity, which colocalize with ESX-1, and which are required for ESX-1 recruitment and assembly. This analysis provides new insights into the molecular assembly of this important determinant of Mtb virulence.

PMID:
22233444
PMCID:
PMC3277861
DOI:
10.1111/j.1365-2958.2011.07958.x
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Wiley Icon for PubMed Central
Loading ...
Support Center