---
OA_place: publisher
OA_type: hybrid
_id: '22269'
abstract:
- lang: eng
text: The divisome apparatus synthesizes septal peptidoglycan (PG) during bacterial
division. In Escherichia coli, the class A penicillin-binding protein (aPBP) called
PBP1b has been implicated in division, but its role in the process has remained
unclear. Here we show using in situ cryo-electron tomography, genetics and other
imaging methods that PBP1b is required to produce a wedge-like density of PG at
the division site and that loss of this structure weakens the division site, making
it hypersusceptible to osmotic lysis. Surprisingly, the activator LpoB needed
for general PBP1b function was not required for its role in division. Of the two
PBP1b isoforms produced in cells, we show that the one with an extended cytoplasmic
N terminus localizes to and functions at the division site, probably via recruitment
by the FtsA component of the divisome. The conservation of aPBPs with extended
cytoplasmic N termini suggests that other Gram-negative bacteria may use similar
mechanisms for division site reinforcement.
acknowledgement: We thank all members of the Bernhardt, Rudner, Navarro and Vettiger
Laboratories for support and helpful conversations. We thank C. Genoud, J. Daraspe,
A. Mucciolo and D. de Bellis at the Electron Microscopy Facility of the University
of Lausanne and E. Jeanvoine for providing access to workstations for cryo-ET image
processing; S. Sterling, C. Borsa, J. Podgorski, P. Vinh Dip, E. Brignole and A.
Osherov at the MIT.nano cryo-EM facility, K. Song and C. Xu at the University of
Massachusetts cryo-EM facility, and R. Walsh and Z. Li at the cryo-EM at Harvard
Medical School facility for providing access to the cryo-EM microscopes and for
all their help, advice and maintenance of cryo-EM equipment. AFM was performed at
the Harvard University Center for Nanoscale Systems (CNS), a member of the National
Nanotechnology Coordinated Infrastructure Network (NNCI), which is supported by
the National Science Foundation under NSF award no. ECCS-2025158. We thank N. S.
Colella for excellent advice on AFM data acquisition and analysis; the MicRoN imaging
core at Harvard Medical School for excellent advice on live cell imaging and maintenance
of fluorescence microscopes; B. Krautz for creating the cartoon illustrations (www.sciencecommunicated.com);
and L. Miles and R. Aeschimann for assistance with strain construction. A.V. was
supported by an EMBO long-term postdoctoral fellowship ALTF_89-2019, the Swiss National
Science Foundation (SNSF) Postdoc.Mobility fellowship P500PB_203143. P.P.N. was
a recipient of early postdoc.mobility and postdoc.mobility fellowships (P2BSP3_188112
and P400PB_199252). This work was also supported by funding from the National Institutes
of Health (R35GM142553 to L.H.C. and R01AI083365 to T.G.B.), investigator funds
from the Howard Hughes Medical Institute (T.G.B.), an SNSF project grant (320030-236243
to A.V.), an SNSF Starting Grant (TMSGI3_218251 to P.P.N.), an SNSF Project grant
(320030-236069 to P.P.N), an SNSF SPARK grant (CRSK-3_237167 to P.P.N.), cryo-EM
funds from the Faculty of Biology and Medicine at University of Lausanne to P.P.N.
and the Foundation Pierre Mercier pour la Science (to P.P.N.).
article_processing_charge: Yes (in subscription journal)
article_type: original
author:
- first_name: Paula P.
full_name: Navarro, Paula P.
last_name: Navarro
- first_name: Andrea
full_name: Vettiger, Andrea
last_name: Vettiger
- first_name: Roman
full_name: Hajdu, Roman
id: ffab949d-133f-11ed-8f02-94de21ace503
last_name: Hajdu
- first_name: Virly Y.
full_name: Ananda, Virly Y.
last_name: Ananda
- first_name: Alejandro
full_name: López-Tavares, Alejandro
last_name: López-Tavares
- first_name: Ernst W.
full_name: Schmid, Ernst W.
last_name: Schmid
- first_name: Johannes C.
full_name: Walter, Johannes C.
last_name: Walter
- first_name: Martin
full_name: Loose, Martin
id: 462D4284-F248-11E8-B48F-1D18A9856A87
last_name: Loose
orcid: 0000-0001-7309-9724
- first_name: Luke H.
full_name: Chao, Luke H.
last_name: Chao
- first_name: Thomas G.
full_name: Bernhardt, Thomas G.
last_name: Bernhardt
citation:
ama: Navarro PP, Vettiger A, Hajdu R, et al. The penicillin-binding protein PBP1b
fortifies the Escherichia coli division site against osmotic rupture. Nature
Microbiology. 2026. doi:10.1038/s41564-026-02403-6
apa: Navarro, P. P., Vettiger, A., Hajdu, R., Ananda, V. Y., López-Tavares, A.,
Schmid, E. W., … Bernhardt, T. G. (2026). The penicillin-binding protein PBP1b
fortifies the Escherichia coli division site against osmotic rupture. Nature
Microbiology. Springer Nature. https://doi.org/10.1038/s41564-026-02403-6
chicago: Navarro, Paula P., Andrea Vettiger, Roman Hajdu, Virly Y. Ananda, Alejandro
López-Tavares, Ernst W. Schmid, Johannes C. Walter, Martin Loose, Luke H. Chao,
and Thomas G. Bernhardt. “The Penicillin-Binding Protein PBP1b Fortifies the Escherichia
Coli Division Site against Osmotic Rupture.” Nature Microbiology. Springer
Nature, 2026. https://doi.org/10.1038/s41564-026-02403-6.
ieee: P. P. Navarro et al., “The penicillin-binding protein PBP1b fortifies
the Escherichia coli division site against osmotic rupture,” Nature Microbiology.
Springer Nature, 2026.
ista: Navarro PP, Vettiger A, Hajdu R, Ananda VY, López-Tavares A, Schmid EW, Walter
JC, Loose M, Chao LH, Bernhardt TG. 2026. The penicillin-binding protein PBP1b
fortifies the Escherichia coli division site against osmotic rupture. Nature Microbiology.
mla: Navarro, Paula P., et al. “The Penicillin-Binding Protein PBP1b Fortifies the
Escherichia Coli Division Site against Osmotic Rupture.” Nature Microbiology,
Springer Nature, 2026, doi:10.1038/s41564-026-02403-6.
short: P.P. Navarro, A. Vettiger, R. Hajdu, V.Y. Ananda, A. López-Tavares, E.W.
Schmid, J.C. Walter, M. Loose, L.H. Chao, T.G. Bernhardt, Nature Microbiology
(2026).
das_tickbox: '1'
dataavailabilitystatement: 'The data, plasmids and strains that support the findings
of this study are available from the corresponding authors by request. Representative
tomograms are deposited in EMDB: EMD-27479 (wild-type), EMD-53351 (∆ponB), EMD-53357(∆lpoB)
and EMD-53363 (∆ponA). Corresponding raw movie frames and stacks of tilt series
are deposited as EMPIAR-11090 (wild type), EMPIAR-13502 (∆ponB), EMPIAR-13513 (∆lpoB)
and EMPIAR-13512 (∆ponA), and will be released upon publication. Other data related
to this manuscript (for example, AFM, light microscopy, growth curves and so on)
can be found on Zenodo at https://doi.org/10.5281/zenodo.20841819 (ref. 101). Source
data are provided with this paper. Scripts used in this study were deposited on
GitHub at https://github.com/NavarroVettiger/Navarro-et-al_2022 and https://github.com/virlyananda/EM-ImageProcessing.'
date_created: 2026-07-12T22:02:19Z
date_published: 2026-07-03T00:00:00Z
date_updated: 2026-07-13T09:22:49Z
day: '03'
ddc:
- '570'
department:
- _id: MaLo
- _id: GradSch
doi: 10.1038/s41564-026-02403-6
external_id:
pmid:
- '42399561'
has_accepted_license: '1'
language:
- iso: eng
license: https://creativecommons.org/licenses/by/4.0/
main_file_link:
- open_access: '1'
url: https://doi.org/10.1038/s41564-026-02403-6
month: '07'
oa: 1
oa_version: Published Version
pmid: 1
publication: Nature Microbiology
publication_identifier:
eissn:
- 2058-5276
publication_status: epub_ahead
publisher: Springer Nature
quality_controlled: '1'
researchdata_availability: yes
scopus_import: '1'
status: public
supplementarymaterial: yes
title: The penicillin-binding protein PBP1b fortifies the Escherichia coli division
site against osmotic rupture
tmp:
image: /images/cc_by.png
legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
short: CC BY (4.0)
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
year: '2026'
...