What is T3SS?

T3SS, the acryonym of Type III Secretion System, is a kind of bacterial organ that protrudes from cellular surface like a　syringe. Components of T3SS are induced and assmbled when bacteria contact with host cells and under special conditions.

A wide range of pathogenic bacteria species contain T3SS apparatus, some with more than one. Most of the bacteria are human or animal pathogens such as Salmonella spp., Shigella spp., Yersinia spp., EPEC, Bordetella spp.,Chlamydia spp.,etc; some are plant pathogenic bacteria, such as Erwinia spp., Pseudomonas syringae, Ralstonia solanacearum, etc; others are endosymbionts such as Rhizobium spp., Sodalis glossinidius, and so on. T3SS plays extremely important roles in microbe-host interactions.

A whole T3SS system is composed of structural components and effectors. The effectors are delivered through the needle-like apparatus structure into host cells that the bacteria contact, exerting a variety of biological functions. Besides, various expression regulators, chaperones and other auxiliary proteins are also important for functional　completement of T3SSs.

Accumulated knowledge about biological activities of bacterial T3SSs is helpful for further understanding bacteria-host interaction and consequent bacterial pathogenecity. It will also provide new considerations or strategies to overcome corresponding infection diseases in human,animals and crops. Meanwhile, exploring mechanisms by wich bacteria interact with hosts could further our envisions for bacterial biology and their co-evolution with eukaryotic hosts. As an application example with the relative knowledge about T3SS effectors' translocation, some effector-based tumor or HIV vaccines were tested to be delivered into animal body, with a final objective of targeting various human diseases.

What is T3DB?

T3DB, Type-III-Secretion-System related database, is aimed to annotate all bacterial T3SS related strucure, effector, regulator, and auxiliary genes. An integrated information system specialized in this focus could facilitate the knowledge exchange between different groups interested in different bacteria.

In this stage of database development, we have been focussing on annotation of T3SS gene information, including their location, sequence, structure, function and homologs. In next stages, we will also annotate and analyze protein interaction between T3SS proteins and host or bacterial proteins, as well as T3SS protein's destination. The expressional regulation and environmental control factors will also be curated.

The database was initiated with the objectives of setting up a systemic T3SS study platform, and promoting information sharing and interchanging among different groups of T3SS or bacteria-host interaction study. Hopefully in the future, more experts or individuals interested in this field can make more contribution to the data annotation and database management.

Reference

Wang Y, Huang H, Sun M, Zhang Q and Guo D. T3DB: an Integrated Database for Bacterial Type III Secretion System. BMC Bioinformatics. 2012, 13:66.  Pubmed