Topological, Functional, and Phylogenetic Analysis of the Cell Division Site Selection Protein MinJ of Bacillus subtilis
- 1Department of Biology Indiana University Bloomington Indiana USA
- 2Department of Chemistry Indiana University Bloomington Indiana USA
Abstract
The Min system disassembles FtsZ‐rings after septation in Bacillus subtilis and is localized to the nascent division plane and cell poles by the protein MinJ. The N‐terminal region of MinJ contains transmembrane segments while the C‐terminal region contains a PDZ domain, but its membrane topology and functional domains are poorly understood. Here, we empirically tested competing topology models and found that MinJ is a nine‐pass transmembrane protein with an extracellular N terminus and a cytoplasmic C terminal PDZ domain. Deletion of the PDZ domain resembled a MinJ null mutation but retained polar localization and interaction with both MinD and DivIVA. Deletion of transmembrane segments 6 and 7 abolished polar localization and interaction with MinD and DivIVA but conferred a hyper‐minicell phenotype that was additive in the absence of MinD. Structural prediction by AlphaFold3 suggests that segments 6 and 7 may constitute an unusual transmembrane β‐sheet, making MinJ perhaps the first of its kind to have such a secondary structure in the plasma membrane. Finally, phylogenetic analyses and structural comparison showed that MinJ sequence and structure are highly conserved within the Firmicutes and tightly co‐conserved with MinD and DivIVA with which it interacts. Our work clarifies the membrane topology and functional organization of MinJ and supports models in which MinJ contributes to bacterial cell division through mechanisms beyond canonical Min system regulation.
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BibTeX
@article{adebiyi2026topological,
title = {{Topological, Functional, and Phylogenetic Analysis of the Cell Division Site Selection Protein MinJ of Bacillus subtilis}},
author = {Kehinde O. Adebiyi and Laura C. Lastra and Jane H. Joncha and Sadie B. Ruesewald and Stephen C. Jacobson and Daniel B. Kearns},
journal = {Molecular Microbiology},
year = {2026},
month = oct,
doi = {10.1111/mmi.70119},
url = {https://doi.org/10.1111/mmi.70119},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Topological, Functional, and Phylogenetic Analysis of the Cell Division Site Selection Protein MinJ of Bacillus subtilis
AU - Kehinde O. Adebiyi
AU - Laura C. Lastra
AU - Jane H. Joncha
AU - Sadie B. Ruesewald
AU - Stephen C. Jacobson
AU - Daniel B. Kearns
PY - 2026
DA - 2026/10/12
JO - Molecular Microbiology
DO - 10.1111/mmi.70119
UR - https://doi.org/10.1111/mmi.70119
AB - The Min system disassembles FtsZ‐rings after septation in Bacillus subtilis and is localized to the nascent division plane and cell poles by the protein MinJ. The N‐terminal region of MinJ contains transmembrane segments while the C‐terminal region contains a PDZ domain, but its membrane topology and functional domains are poorly understood. Here, we empirically tested competing topology models and found that MinJ is a nine‐pass transmembrane protein with an extracellular N terminus and a cytoplasmic C terminal PDZ domain. Deletion of the PDZ domain resembled a MinJ null mutation but retained polar localization and interaction with both MinD and DivIVA. Deletion of transmembrane segments 6 and 7 abolished polar localization and interaction with MinD and DivIVA but conferred a hyper‐minicell phenotype that was additive in the absence of MinD. Structural prediction by AlphaFold3 suggests that segments 6 and 7 may constitute an unusual transmembrane β‐sheet, making MinJ perhaps the first of its kind to have such a secondary structure in the plasma membrane. Finally, phylogenetic analyses and structural comparison showed that MinJ sequence and structure are highly conserved within the Firmicutes and tightly co‐conserved with MinD and DivIVA with which it interacts. Our work clarifies the membrane topology and functional organization of MinJ and supports models in which MinJ contributes to bacterial cell division through mechanisms beyond canonical Min system regulation.
SN - 0950-382X
SN - 1365-2958
ER -