Listeria monocytogenes virulence factor secretion: don't leave the cell without a chaperone

Laty A Cahoon,Nancy E Freitag

doi:10.3389/fcimb.2014.00013

Laty A Cahoon, Nancy E Freitag

Open Access

https://doi.org/10.3389/fcimb.2014.00013

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Abstract

In Gram-positive bacteria, the secretion of proteins requires translocation of polypeptides across the bacterial membrane into the highly charged environment of the membrane-cell wall interface. Here, proteins must be folded and often further delivered across the matrix of the cell wall. While many aspects of protein secretion have been well studied in Gram-negative bacteria which possess both an inner and outer membrane, generally less attention has been given to the mechanics of protein secretion across the single cell membrane of Gram-positive bacteria. In this review, we focus on the role of a post-translocation secretion chaperone in Listeria monocytogenes known as PrsA2, and compare what is known regarding PrsA2 with PrsA homologs in other Gram-positive bacteria. PrsA2 is a member of a family of membrane-associated lipoproteins that contribute to the folding and stability of secreted proteins as they cross the bacterial membrane. PrsA2 contributes to the integrity of the L. monocytogenes cell wall as well as swimming motility and bacterial resistance to osmotic stress; however its most critical role may be its requirement for L. monocytogenes virulence and viability within host cells. A better understanding of the role of PrsA2 and PrsA-like homologs will provide insight into the dynamics of protein folding and stability in Gram-positive bacteria and may result in new strategies for optimizing protein secretion as well as inhibiting the production of virulence factors.

Highlights

Bacteria are generally highly adaptable creatures that must interface with their varied environments to acquire nutrients, mitigate stress conditions, establish a replication niche, and avoid or eliminate undesirables, such as immune effector cells bent on bacterial destruction
We focus on the role of a post-translocation secretion chaperone in Listeria monocytogenes known as PrsA2, and compare what is known regarding PrsA2 with PrsA homologs in other Gram-positive bacteria
It has recently become apparent that L. monocytogenes is an excellent model system for the investigation of Gram-positive protein secretion and the associated role of a critical post-translocation secretion chaperone known as PrsA2 (Alonzo et al, 2009, 2011; Zemansky et al, 2009; Alonzo and Freitag, 2010; Forster et al, 2011)

Summary

Introduction

Bacteria are generally highly adaptable creatures that must interface with their varied environments to acquire nutrients, mitigate stress conditions, establish a replication niche, and avoid or eliminate undesirables, such as immune effector cells bent on bacterial destruction. L. monocytogenes PrsA2 contributes to multiple facets of bacterial pathogenesis and is essential for virulence (Alonzo et al, 2009; Zemansky et al, 2009), reflecting the apparent requirement of PrsA2 for the folding and secretion of a number of proteins (Alonzo and Freitag, 2010).

Results

Conclusion