Interaction of the cyclic-di-GMP binding protein FimX and the Type 4 pilus assembly ATPase promotes pilus assembly.
Interaction of the cyclic-di-GMP binding protein FimX and the Type 4 pilus assembly ATPase promotes pilus assembly.
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DOI：
10.1371/journal.ppat.1006594
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发表时间：
2017-08
期刊：
影响因子：
6.7
通讯作者：
Kazmierczak BI
中科院分区：
文献类型：
--
作者：
Jain R;Sliusarenko O;Kazmierczak BI
Type IVa pili (T4P) are bacterial surface structures that enable motility, adhesion, biofilm formation and virulence. T4P are assembled by nanomachines that span the bacterial cell envelope. Cycles of T4P assembly and retraction, powered by the ATPases PilB and PilT, allow bacteria to attach to and pull themselves along surfaces, so-called “twitching motility”. These opposing ATPase activities must be coordinated and T4P assembly limited to one pole for bacteria to show directional movement. How this occurs is still incompletely understood. Herein, we show that the c-di-GMP binding protein FimX, which is required for T4P assembly in Pseudomonas aeruginosa, localizes to the leading pole of twitching bacteria. Polar FimX localization requires both the presence of T4P assembly machine proteins and the assembly ATPase PilB. PilB itself loses its polar localization pattern when FimX is absent. We use two different approaches to confirm that FimX and PilB interact in vivo and in vitro, and further show that point mutant alleles of FimX that do not bind c-di-GMP also do not interact with PilB. Lastly, we demonstrate that FimX positively regulates T4P assembly and twitching motility by promoting the activity of the PilB ATPase, and not by stabilizing assembled pili or by preventing PilT-mediated retraction. Mutated alleles of FimX that no longer bind c-di-GMP do not allow rapid T4P assembly in these assays. We propose that by virtue of its high-affinity for c-di-GMP, FimX can promote T4P assembly when intracellular levels of this cyclic nucleotide are low. As P. aeruginosa PilB is not itself a high-affinity c-di-GMP receptor, unlike many other assembly ATPases, FimX may play a key role in coupling T4P mediated motility and adhesion to levels of this second messenger. Type IV pili (T4P) are assembled on the surfaces of many bacterial pathogens and commensals through the action of specialized assembly machines whose components and structures are the subject of intense study. Repeated cycles of T4P assembly, attachment and retraction allow bacteria to move or “twitch” along surfaces, efficiently colonize and intoxicate host tissues, and elaborate multicellular structures such as biofilms. Assembly and retraction are powered by specific ATPases, PilB and PilT respectively, but the manner in which their activity is coordinated is still poorly understood. In this work, we provide evidence that a high-affinity c-di-GMP binding protein of Pseudomonas aeruginosa, FimX, interacts with the ATPase PilB and promotes PilB-dependent assembly of T4P. Live cell imaging of twitching bacteria shows that FimX localizes to the leading pole of motile P. aeruginosa and that its recruitment requires both components of the T4P assembly machine and the PilB ATPase. Our work highlights a novel regulatory strategy employed by P. aeruginosa to control assembly of this broadly conserved virulence factor.
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DOI：
10.1126/science.aad2001
发表时间：
2016-03-11
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Chang YW;Rettberg LA;Treuner-Lange A;Iwasa J;Søgaard-Andersen L;Jensen GJ
通讯作者：
Jensen GJ
影响因子：
3.2
作者：
Friedrich, Carmen;Bulyha, Iryna;Sogaard-Andersen, Lotte
通讯作者：
Sogaard-Andersen, Lotte
DOI：
10.1073/pnas.1105073108
发表时间：
2011-08-02
影响因子：
11.1
作者：
Jin, Fan;Conrad, Jacinta C.;Wong, Gerard C. L.
通讯作者：
Wong, Gerard C. L.
影响因子：
3.2
作者：
Alm, RA;Bodero, AJ;Mattick, JS
通讯作者：
Mattick, JS
影响因子：
5.6
作者：
Ayers, M.;Sampaleanu, L. M.;Burrows, L. L.
通讯作者：
Burrows, L. L.