PUBLICATIONS

Complete list of publications can be found on NCBI:
https://www.ncbi.nlm.nih.gov/Marc_Bramkamp

 

New in press

FtsZ induces membrane deformations via torsional stress upon GTP hydrolysis

 

FtsZ is a key component in bacterial cell division, being the primary protein of the presumably contractile Z ring. In vivo and in vitro, it shows two distinctive features that could so far, however, not be mechanistically linked: self-organization into directionally treadmilling vortices on solid supported membranes, and shape deformation of flexible liposomes. In cells, circumferential treadmilling of FtsZ was shown to recruit septum-building enzymes, but an active force production remains elusive. To gain mechanistic understanding of FtsZ dependent membrane deformations and constriction, we design an in vitro assay based on soft lipid tubes pulled from FtsZ decorated giant lipid vesicles (GUVs) by optical tweezers. FtsZ filaments actively transform these tubes into spring-like structures, where GTPase activity promotes spring compression. Operating the optical tweezers in lateral vibration mode and assigning spring constants to FtsZ coated tubes, the directional forces that FtsZ-YFP-mts rings exert upon GTP hydrolysis can be estimated to be in the pN range. They are sufficient to induce membrane budding with constricting necks on both, giant vesicles and E.coli cells devoid of their cell walls. We hypothesize that these forces result from torsional stress in a GTPase activity dependent manner.

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Bidirectional FtsZ treadmilling rings yield directional screw-like lipid membrane deformations.

a FtsZ-YFP-mts ring structures externally decorating GUVs (scale bar = 10 µm).

b After GUV deflation, inwards conical deformations emerged from FtsZ rings (GUVs: N > 20) (scale bar = 5 µm).

c Inspired by deformations in (b), we designed a PDMS microstructure with inwards conical geometry covered with a supported lipid bilayer (SLB). The imaging plane was chosen to have a cross-section of 1–2-µm diameter (scale bar = 5 µm).

d Inside cones, FtsZ-YFP-mts self-assembled into dynamic vortices (Supplementary Movie S1) (scale bar = 5 µm).

e A representative kymograph (N > 3) showed negative and positive slopes indicating the presence of clockwise and anticlockwise directions.

Nat Commun, 12(1):3310. doi: 10.1038/s41467-021-23387-3.

 

Key publications

Flotillin mediated membrane fluidity controls peptidoglycan synthesis and MreB movement

Zielińska A, Savietto A, de Sousa Borges A, Martinez D, Berbon M, Roelofsen JR, Hartman AM, de Boer R, van der Klei IJ, Hirsch AKH, Habenstein B, Bramkamp M, Scheffers D-J

Elife, 2020, 9:e57179. doi: 10.7554/eLife.57179

Chromosome organization by a conserved condensin–ParB system in the actinobacterium
Corynebacterium glutamicum

Böhm K, Giacomelli G, Schmidt A, Imhof A, Koszul R, Marbouty M, Bramkamp M

Nat Commun, 2020, 11(1):1485. doi: 10.1038/s41467–020–15238–4

The Antituberculosis Drug Ethambutol Selectively Blocks Apical Growth in CMN Group Bacteria

Schubert K, Sieger B, Meyer F, Giacomelli G, Böhm K, Rieblinger A, Lindenthal L, Sachs N, Wanner G, Bramkamp M

mBio, 2017 Feb 7, vol. 8 no. 1 e02213-16. doi: 10.1128/mBio.02213-16

A dynamin-like protein involved in bacterial cell membrane surveillance under environmental
stress

Sawant P, Eissenberger K, Karier L, Mascher T, Bramkamp M

Environ Microbiol, 2016, 18: 2705–2720. doi:10.1111/1462-2920.13110

A prophage-encoded actin-like protein required for efficient viral DNA replication in bacteria

Donovan C, Heyer A, Pfeifer E, Polen T, Wittmann A, Krämer R, Frunzke J, Bramkamp M

Nucleic Acids Res, 2015 Apr 27. pii: gkv374. doi: 10.1093/nar/gkv374

Flotillins functionally organize the bacterial membrane

Bach JN, Bramkamp M

Mol Microbiol, 2013 Jun, 88(6):1205-17. doi: 10.1111/mmi.12252

A novel component of the division-site selection system of Bacillus subtilis and a new mode of
action for the division inhibitor MinCD

Bramkamp M, Emmins R, Weston L, Donovan C, Daniel RA, Errington J

Mol Microbiol, 2008 Dec, 70(6):1556-69.

 

Press releases

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06/03/2021: Molecular powerhouse of the cell division motor

Interdisciplinary research teams from the Max-Planck-Institute of Biochemistry and the Institute of General Microbiology at Kiel University show that dynamic proteins can deform the cell membrane of bacterial cells and thus initiate cell division.

CAU press release: https://www.uni-kiel.de/en/university/details/news/124-ramirez-naturecomms

07/15/2020: How proteins regulate the outer envelope of bacterial cells

Research team in Kiel has identified the involvement of so-called flotillin proteins in the fluidization of bacterial cell membranes.

CAU press release: https://www.uni-kiel.de/en/university/details/news/173-zielinska-elife

03/20/2020: New piece of the puzzle in the architecture of life

Kiel research team investigates previously-unknown reproduction mechanism in the biotech-relevant bacterium Corynebacterium glutamicum.

CAU press release: https://www.uni-kiel.de/en/university/details/news/083-bramkamp-naturecomms

2017: Many forks make light work

LMU press release about new insights into the control of DNA replication and cell division in Corynebacterium glutamicum, a biotechnologically important microorganism, could help to optimize the industrial production of amino acids.

https://phys.org/news/2017-06-forks.html

2017: Lock-out on the building site

LMU press release about the selective block of apical growth in CMN group bacteria caused by the antituberculosis drug Ethambutol. Ethambutol has long been part of the standard therapy for tuberculosis. LMU researchers now describe how the antibiotic acts on the bacterium that causes the disease: It specifically inhibits growth of the cell wall from the cell poles.

https://phys.org/news/2017-02-lock-out-site.html