T6SS-effector hunters uncover PIX: a novel delivery/marker domain:
cell.com/trends/microbi…

T6SS-effector hunters uncover PIX: a novel delivery/marker domain dlvr.it/T6BC8Y

Exciting news! Our latest preprint is out, showcasing the work of Nicolas Flaugnatti on T6SS & capsule in Acinetobacter baumannii.
Congratulations Nico! 🍾🥳
🧵below .... 1/x

Capsular Polysaccharide Restrains Type VI Secretion in Acinetobacter baumannii biorxiv.org/content/10.110…

Our paper on the discovery of novel bacterial T6SS effectors and their immunity proteins is out in Molecular Systems Biology!

We show how AlphaFold-Multimer is a great tool for predicting these protein pairs as they have a very stable protein-protein interaction.

Did you hear about PIX, the new T6SS effector delivery domain uncovered by Dor Salomon lab? I wrote about it here in context with MIX, FIX and RIX sciencedirect.com/science/articl… in Trends in Microbiology. Don't miss the original research article in Cell Reports shorturl.at/bhqrY

So Nico tested whether the capsule impacts A. baumannii's own T6SS comparing WT and capsule-minus strains (∆itrA of strain A118) and it does 🤓 as observed by enhanced E. coli killing and Hcp secretion in the absence of capsule ... 6/x

Moreover, the T6SS impairment was further enhanced when capsular polysaccharide (CPS) was overproduced due to genetic modifications .... 7/x

SubMIC concentrations of chloramphenicol turned out to also enhance CPS production in A. baumannii strain A118 and, consequently, to impair its T6SS activity in a CPS-dependent manner ..... 9/x

Yesterday my PhD student Gabi, cotutored with Miguel de la Cruz BUAP , got her paper published in mSphere , please take a look! journals.asm.org/doi/10.1128/ms…
Here the role of the nucleoide associated protein HU as regulator of T6SS in E. cloacae is explored. Congrats Gabi!

Collectively, our work contributes to a better understanding of the dynamic relationship between T6SS and CPS in A. baumannii.
Congrats again to Nico 🎉🥳 & thanks to Loriane and Mary 🙏 for technical assistance & help w/ TEM .... end
Enjoy the read 🤓
biorxiv.org/content/10.110…

Finally, Nico observed 🔍 that secretion-impaired strains (e.g., due to T6SS sheath deficiency or CPS overproduction) lack the T6SS inner tube protein Hcp during growth in stationary phase 🤔 ..... 12/x

Turns out that CPS overproduction had a much stronger effect on T6SS than the complete absence of TslA, suggesting that the lack of cell-cell contact sensing was not the only reason for T6SS impairment under such conditions ....11/x

What a lovely spotlight on our recent work, written by the wonderful Patricia Bernal who summarizes current knowledge on #T6SS delivery domains. sciencedirect.com/science/articl…

Burkholderia’s secret weapon. Miro Plum Basler Lab uncover a stealthy mechanism by which B. thailandensis spreads between host cells. #Bacteria form membrane protrusions & lyse them via T6SS-5, which prevents recognition by host cell defense mechanisms cell.com/cell-host-micr…

Over the last decade, our team has been unraveling the mysteries of the type VI secretion system (T6SS 🏹) in V. cholerae. We've discovered how it cleverly links with its competence state to acquire genes 🧬 from defeated neighbors ... 2/x

science.org/doi/10.1126/sc…

To investigate this intriguing paradox, we focused on Acinetobacter baumannii🦠, a frequently antibiotic-resistant pathogen.
Shoutout to Mario Feldman & Salcedo Lab for their groundbreaking work on T6SS In A.b. 🤩... 5/x
(e.g., journals.plos.org/plosone/articl…
pnas.org/doi/full/10.10…)

Very interesting paper published by M. Baseler’s group @Biozentrum Universität Basel. Burkholderia thailandensis uses #T6SS for „stealth mode“ to circumvent elimination via autophagy: sciencedirect.com/science/articl…

T6SS-effector hunters uncover PIX: a novel delivery/marker domain

Trends in Microbiology Spotlight by Patricia Bernal on the Cell Reports paper by Andrea Carobbi et al from Dor Salomon (and Guido Sessa)

sciencedirect.com/science/articl…

However, a couple of years ago, there was a twist in our T6SS research! We've found that several microbiota members, including many Klebsiella strains, are resisting T6SS attacks. Their secret? A protective capsule .... 3/x

nature.com/articles/s4146…

Interestingly, some capsulated bacteria harbor themselves T6SS gene clusters, presenting a paradox:
How can a membrane-associated capsule both obstruct external T6SS attacks and facilitate the secretion of its own T6SS components 🤔? ..... 4/x