Trimeric autotransporter adhesin

Taabasic1

Trimeric Autotransporter Adhesin

A Trimeric Autotransporter Adhesin (TAA) is a type of bacterial adhesin protein found in certain Gram-negative bacteria. TAAs are involved in mediating the attachment of bacteria to host cells, facilitating the initial stages of infection. These proteins are characterized by their trimeric structure and their ability to be secreted by the bacterial cell through a process known as autotransport.

Structure

Trimeric autotransporter adhesins consist of three identical protein subunits that form a trimeric complex. Each subunit typically contains distinct domains responsible for functions such as adhesion to host cells, self-association into trimers, and translocation across the bacterial outer membrane. The trimeric structure of TAAs allows for increased avidity in binding to host cell receptors.

Function

The primary function of trimeric autotransporter adhesins is to facilitate the attachment of bacteria to host cells. By binding to specific receptors on the surface of host cells, TAAs promote bacterial colonization and the establishment of infection. In addition to their adhesive properties, some TAAs have been shown to modulate host immune responses and contribute to bacterial virulence.

Role in Pathogenesis

TAAs play a crucial role in the pathogenesis of various bacterial species. These adhesins are often expressed by pathogens that cause diseases such as bacterial pneumonia, urinary tract infection, and meningitis. By promoting bacterial adhesion and colonization, TAAs contribute to the ability of pathogens to evade host defenses and cause disease.

Examples

One well-studied example of a trimeric autotransporter adhesin is the Yersinia adhesin A (YadA) protein found in Yersinia enterocolitica and Yersinia pseudotuberculosis. YadA is known for its role in promoting bacterial adhesion to host cells and modulating host immune responses. Other examples of TAAs include the Hia protein in Haemophilus influenzae and the Hsf protein in Haemophilus ducreyi.

Clinical Significance

Understanding the role of trimeric autotransporter adhesins in bacterial pathogenesis is important for the development of novel therapeutic strategies. Targeting TAAs with vaccines or inhibitors could potentially prevent bacterial adhesion and colonization, leading to improved treatment outcomes for infectious diseases caused by pathogenic bacteria.

See also

• Bacterial adhesin
• Autotransporter
• Yersinia adhesin A