FisB relies on homo-oligomerization and lipid binding to catalyze membrane fission in bacteria.

TitleFisB relies on homo-oligomerization and lipid binding to catalyze membrane fission in bacteria.
Publication TypeJournal Article
Year of Publication2021
AuthorsLandajuela, A, Braun, M, Rodrigues, CDA, Martínez-Calvo, A, Doan, T, Horenkamp, F, Andronicos, A, Shteyn, V, Williams, ND, Lin, C, Wingreen, NS, Rudner, DZ, Karatekin, E
JournalPLoS Biol
Volume19
Issue6
Paginatione3001314
Date Published2021 06
ISSN1545-7885
KeywordsBacillus subtilis, Bacterial Proteins, Catalysis, Cell Membrane, Clostridium perfringens, Green Fluorescent Proteins, Membrane Lipids, Membrane Proteins, Models, Molecular, Mutant Proteins, Protein Binding, Protein Domains, Protein Multimerization
Abstract

<p>Little is known about mechanisms of membrane fission in bacteria despite their requirement for cytokinesis. The only known dedicated membrane fission machinery in bacteria, fission protein B (FisB), is expressed during sporulation in Bacillus subtilis and is required to release the developing spore into the mother cell cytoplasm. Here, we characterized the requirements for FisB-mediated membrane fission. FisB forms mobile clusters of approximately 12 molecules that give way to an immobile cluster at the engulfment pole containing approximately 40 proteins at the time of membrane fission. Analysis of FisB mutants revealed that binding to acidic lipids and homo-oligomerization are both critical for targeting FisB to the engulfment pole and membrane fission. Experiments using artificial membranes and filamentous cells suggest that FisB does not have an intrinsic ability to sense or induce membrane curvature but can bridge membranes. Finally, modeling suggests that homo-oligomerization and trans-interactions with membranes are sufficient to explain FisB accumulation at the membrane neck that connects the engulfment membrane to the rest of the mother cell membrane during late stages of engulfment. Together, our results show that FisB is a robust and unusual membrane fission protein that relies on homo-oligomerization, lipid binding, and the unique membrane topology generated during engulfment for localization and membrane scission, but surprisingly, not on lipid microdomains, negative-curvature lipids, or curvature sensing.</p>

DOI10.1371/journal.pbio.3001314
Alternate JournalPLoS Biol
PubMed ID34185788
PubMed Central IDPMC8274934
Grant ListDP2 GM114830 / GM / NIGMS NIH HHS / United States
R01 GM114513 / GM / NIGMS NIH HHS / United States
R01 GM132114 / GM / NIGMS NIH HHS / United States
R01 NS113236 / NS / NINDS NIH HHS / United States