flagellin

The bacterial flagellum is made up of the protein flagellin.

Salmonella use this technique to switch between different types of the protein flagellin.

Some bacteria are able to switch between multiple flagellin genes in order to evade this response.

The propensity of the immune response to flagellin may be explained by two facts:

Bacterial flagellin and plant disease resistance, published by Zipfel.

As such, the protein that makes up the flagellar filament, flagellin, is quite similar among all flagellated bacteria.

NLRC4 can specifically recognise flagellin and then trigger caspase-1 dependent pyroptosis.

By recognizing flagellin and/or profilin present on certain microbes, it helps propagate a host immune response.

But there are also genes expressed solely in the Bvg state, most notably the flagellin gene flaA.

In addition, a 22-amino acid sequence (flg22) of the conserved N-terminal part of flagellin is known to activate plant defence mechanisms.

TLR5 recognizes flagellin.

In vitro, flagellar filaments assemble spontaneously in a solution containing purified flagellin as the sole protein.

Examples of these microbial compounds that elicit plant basal defense include bacterial flagellin or lipopolysaccharides, or fungal chitin.

The structure of flagellin is responsible for the helical shape of the flagellar filament, which is important for its proper function.

Other molecules (bacterial lipopeptides, flagellin, and unmethylated DNA) were shown in turn to provoke host responses that are normally protective.

The filament is approximately 20 nm in diameter and consists of several protofilaments, each made up of thousands of flagellin subunits.

The bacteria stop producing the protein flagellin to conserve energy and nutrients by changing the mix of proteins which they express in response to the changed chemical surroundings.

There exists a specific innate immune receptor that recognizes flagellin, Toll-like receptor 5 (TLR5).

This gene product is expressed in myelomonocytic cells, and recognizes bacterial flagellin, a principal component of bacterial flagella and a virulence factor.

In vivo FLS2 and BAK1 form a complex, in a specific ligand-dependent manner, within the first minutes of stimulation with flagellin.

Plants carrying bak1 mutations show normal flagellin binding but abnormal early and late flagellin-triggered responses, indicating that BAK1 acts as a positive regulator in signalling.

IPAF senses flagellin from Salmonella typhimurium, Pseudomonas aeruginosa, Listeria monocytogenes.

Bacterial flagella grow by the addition of flagellin subunits at the tip; archaeal flagella grow by the addition of subunits to the base.

TLR11 in mouse intestine recognizes this flagellin which causes dimerization of the receptor, activation of NF-κB and production of inflammatory cytokines.

Protein glycosylation, particularly of pilin and flagellin, is a recent focus of research by several groups and it has been shown to be important for adhesion and invasion during bacterial infection.