Control of septum thickness by the curvature of SepF polymers
Journal article, 2021

Gram-positive bacteria divide by forming a thick cross wall. How the thickness of this septal wall is controlled is unknown. In this type of bacteria, the key cell division protein FtsZ is anchored to the cell membrane by two proteins, FtsA and/or SepF. We have isolated SepF homologs from different bacterial species and found that they all polymerize into large protein rings with diameters varying from 19 to 44 nm. Interestingly, these values correlated well with the thickness of their septa. To test whether ring diameter determines septal thickness, we tried to construct different SepF chimeras with the purpose to manipulate the diameter of the SepF protein ring. This was indeed possible and confirmed that the conserved core domain of SepF regulates ring diameter. Importantly, when SepF chimeras with different diameters were expressed in the bacterial host Bacillus subtilis, the thickness of its septa changed accordingly. These results strongly support a model in which septal thickness is controlled by curved molecular clamps formed by SepF polymers attached to the leading edge of nascent septa. This also implies that the intrinsic shape of a protein polymer can function as a mold to shape the cell wall.



cell division

Bacillus subtilis


Michaela Wenzel

University of Amsterdam

Chalmers, Biology and Biological Engineering, Chemical Biology

Ilkay N. Celik Gulsoy

University of Amsterdam

Yongqiang Gao

Harvard Medical School

University of Amsterdam

Zihao Teng

University of Amsterdam

Joost Willemse

Leiden University

Martijn Middelkamp

University of Groningen

Mariska G. M. van Rosmalen

Vrije Universiteit Amsterdam

Per W. B. Larsen

University of Amsterdam

Nicole N. van der Wel

University of Amsterdam

Gijs J. L. Wuite

Vrije Universiteit Amsterdam

Wouter H. Roos

University of Groningen

Leendert W. Hamoen

University of Amsterdam

Proceedings of the National Academy of Sciences of the United States of America

0027-8424 (ISSN) 1091-6490 (eISSN)

Vol. 118 2 e2002635118

Subject Categories

Biochemistry and Molecular Biology


Medical Biotechnology (with a focus on Cell Biology (including Stem Cell Biology), Molecular Biology, Microbiology, Biochemistry or Biopharmacy)





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2/8/2021 3