Functional genomic analysis of the Bacillus subtilis Tat pathway for protein secretion

Protein secretion from Bacillus species is a major industrial production tool with a market of over $1 billion per year. However, standard export technologies, based on the well-characterised general secretory (Sec) pathway, are frequently inapplicable for the production of proteins. The recently discovered twin-arginine translocation (Tat) pathway offers additional potential to transport proteins. Here we review the use of functional genomic and proteomic approaches to explore the Tat pathway of Bacillus subtilis. The properties of Tat pathway components and the twin-arginine signal peptides that direct proteins into this pathway are discussed. Where appropriate, a comparison is made with Tat systems from other organism, such as Escherichia coli. Recent findings with the latter organism in particular provide proof-of-principle that the Tat pathway can be exploited for the production of Sec-incompatible proteins.