Thread by @NikaPende

Very proud to see it finally out! 🥰🦠🔬
go.nature.com/3vW4kEg
Here is a thread with our major findings 1/9

2/9 Many #Archaea divide by #FtsZ, but how is the Z-ring anchored to the membrane? We demonstrate that #SepF does it, but not quite like in Bacteria 😉 Great collaboration by @SGribaldo @AdriaSogues @AM_Wehenkel @institutpasteur @Archaea_Vienna.

3/9 We used the human associated methanogen Methanobrevibacter smithii as a new model and showed that SepF transiently co-localizes with FtsZ at the septum and possibly primes the future division plane by 3D SIM and quantitative microscopy analysis of immunolabeled cells.

4/9 Like in bacteria, archaeal M. smithii SepF binds to membranes and to FtsZ, inducing filament bundling. However, high-resolution crystal structures of archaeal SepF reveal a unique homodimerization interface through the beta-beta interface unlike the bacterial alpha-alpha.

5/9 Structure of M. smithii SepF in complex with FtsZ C-terminal domain (CTD) revealed archaeal specific binding features: archaeal-specific η1 insertion forms a wider binding pocket and the C-terminal region of FtsZ-CTD largely binds to only one monomer of the functional dimer.

6/9 SepF and FtsZ are widely present in both Archaea and Bacteria, but when did they originate? Phylogenetic analysis indicates that the two proteins date back to the Last Universal Common Ancestor (LUCA), while the other known anchors like FtsA emerged in Bacteria.

7/9 We speculate that SepF/FtsZ likely formed the core of a minimal division system in the LUCA, and that the archaeal mode of SepF/FtsZ interaction might reflect an ancestral feature, which then shifted in Bacteria possibly to accommodate the emergence of the complex divisome.

8/9 In conclusion, our interdisciplinary work adds an important piece to the still largely elusive machinery for archaeal cell division and the newly developed immunolabelling protocol in this study sets the cell-walled M. smithii as a new experimental model to study it.

9/9 We are happy to publish this story back-to-back with @Archaellum @PhillipNussbau1 who showed that Archaeal SepF is essential for cell division in Haloferax volcanii. If you want to know how this story came to be, check out our "behind the paper" go.nature.com/2RkLZl9