MinD is a septum site-determining protein and ParA-family Walker-type ATPase essential for correct placement of the bacterial cell division site. MinD acts in concert with MinC to form an inhibitory complex that blocks polar Z ring formation, preventing aberrant division at cell poles. The ATP-bound form of MinD dimerizes and recruits MinC to the membrane, where MinC directly inhibits FtsZ polymerization. Unlike E. coli, B. subtilis lacks MinE and instead uses MinJ as the topological determinant that bridges MinD/MinC to DivIVA, which senses negative membrane curvature at poles and septa. MinD's ATPase cycle controls membrane residence time and drives dynamic polar/septal enrichment patterns that prevent polar septum formation and promote divisome disassembly after cytokinesis. Loss of MinD leads to minicell formation due to aberrant polar division.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
|
GO:0005524
ATP binding
|
IBA
GO_REF:0000033 |
ACCEPT |
Summary: MinD is a ParA-family Walker-type ATPase with a well-characterized ATP binding site at residues 11-18 (P-loop motif). ATP binding is essential for MinD function and drives dimerization, which is required for MinC recruitment and membrane association. This is a core molecular function supported by extensive phylogenetic and biochemical evidence.
Reason: ATP binding is a core molecular function of MinD. The protein contains a characteristic P-loop NTPase domain (InterPro: IPR027417) with an ATP binding site at residues 11-18 documented in UniProt. The IBA annotation is well-supported by phylogenetic inference and aligns with the conserved function across MinD family proteins. Biochemical studies confirm ATP binding is essential for MinD dimerization and function.
Supporting Evidence:
UniProt:Q01464
BINDING 11..18 /ligand="ATP" /ligand_id="ChEBI:CHEBI:30616"
file:BACSU/minD/minD-deep-research-falcon.md
MinD is an ATPase whose hydrolysis is strongly stimulated by membrane binding
|
|
GO:0016887
ATP hydrolysis activity
|
IBA
GO_REF:0000033 |
ACCEPT |
Summary: MinD possesses intrinsic ATP hydrolysis activity that is membrane-activated. Recent biochemical studies report kcat of approximately 36.27 h^-1 in liposome assays. The ATPase cycle controls membrane residence time and is essential for MinD patterning and function in division site selection.
Reason: ATP hydrolysis is a core enzymatic function of MinD essential for its role in division site selection. Unlike E. coli MinD which requires MinE for stimulation, B. subtilis MinD ATPase is activated by membrane binding alone. The ATPase cycle drives the dynamic membrane association/dissociation that creates the spatial gradients necessary for correct division site positioning. This IBA annotation is strongly supported by phylogenetic inference and recent biochemical characterization.
Supporting Evidence:
file:BACSU/minD/minD-deep-research-falcon.md
MinD ATPase activity is strongly stimulated by membrane binding, with kcat approximately 36.27 h^-1 in liposome assays
PMID:33849976
MinD, a protein that belongs to the WACA (Walker A cytomotive ATPase) family
|
|
GO:0005829
cytosol
|
IBA
GO_REF:0000033 |
ACCEPT |
Summary: MinD is found in the cytosol as part of its dynamic cycling between cytoplasm and membrane. The ATP-free monomeric form of MinD is predominantly cytosolic, while ATP-bound dimeric MinD associates with the membrane. This dynamic localization is essential for MinD function.
Reason: MinD cycles between cytosol and membrane as part of its functional mechanism. Single-molecule tracking studies show that MinD exists in multiple diffusion states including a fast cytosolic fraction (D approximately 0.60 um^2/s). The cytosolic pool represents the ATP-free/monomeric form that is part of the functional cycle. This annotation correctly captures one aspect of MinD's dynamic localization.
Supporting Evidence:
file:BACSU/minD/minD-deep-research-falcon.md
Representative diffusion-state fractions for MinD populations (WT example): fast approximately 22.3% at D approximately 0.60 um^2 s^-1
|
|
GO:0009898
cytoplasmic side of plasma membrane
|
IBA
GO_REF:0000033 |
ACCEPT |
Summary: MinD localizes to the cytoplasmic side of the plasma membrane via two C-terminal amphipathic helices (MTS1 and MTSL). Membrane association is enhanced in the ATP-bound dimeric state and is essential for recruiting MinC to inhibit polar FtsZ ring formation. MinD enriches at poles and active division sites.
Reason: Membrane localization is a core aspect of MinD function. B. subtilis MinD possesses two C-terminal amphipathic alpha-helices (MTS1 and MTSL) that mediate membrane targeting. Unlike E. coli MinD which oscillates rapidly pole-to-pole, B. subtilis MinD forms polar and septal enrichments with dynamic recruitment to division sites. UniProt annotates MinD as a peripheral membrane protein associated with the cell membrane.
Supporting Evidence:
UniProt:Q01464
SUBCELLULAR LOCATION: Cell membrane; Peripheral membrane protein.
PMID:28674273
Bacillus subtilis MinD has two amphipathic α-helices rich in basic amino acid residues at its C-terminus
file:BACSU/minD/minD-deep-research-falcon.md
In B. subtilis MinD enriches at poles and active division sites (septal enrichment)
|
|
GO:0000166
nucleotide binding
|
IEA
GO_REF:0000043 |
ACCEPT |
Summary: This is a parent term of GO:0005524 (ATP binding). MinD specifically binds ATP through its P-loop motif. The more specific ATP binding annotation already captures the core function.
Reason: This IEA annotation from UniProtKB keyword mapping is correct but less specific than the ATP binding (GO:0005524) annotation already present via IBA evidence. Since MinD is specifically an ATP-binding ATPase, this broader term is technically accurate but redundant with the more informative ATP binding annotation. Acceptable to retain as it does not contradict other annotations.
|
|
GO:0000917
division septum assembly
|
IEA
GO_REF:0000043 |
MODIFY |
Summary: MinD is involved in the regulation of division septum assembly, specifically by preventing inappropriate polar septum formation and promoting divisome disassembly after cytokinesis. However, MinD's role is inhibitory/regulatory rather than directly assembling the septum.
Reason: While MinD is clearly involved in division septum-related processes, the term 'division septum assembly' (GO:0000917) implies direct participation in building the septum. MinD's actual role is to NEGATIVELY regulate septum formation at inappropriate sites (cell poles) and to promote disassembly of the divisome after septation. More appropriate terms would be 'regulation of division septum assembly' (GO:0032955) or 'negative regulation of division septum assembly' (GO:0010974), or 'division septum site selection' (GO:0000918). The MinCDJ system prevents polar Z-ring activity and promotes divisome disassembly.
Proposed replacements:
division septum site selection
regulation of division septum assembly
Supporting Evidence:
PMID:20352045
the main function of the Min system is to prevent minicell formation adjacent to recently completed division sites by promoting the disassembly of the cytokinetic ring
file:BACSU/minD/minD-deep-research-falcon.md
MinCDJ acting downstream of site selection to prevent re-initiation and to assist divisome disassembly
|
|
GO:0005524
ATP binding
|
IEA
GO_REF:0000043 |
ACCEPT |
Summary: Duplicate of the IBA annotation for ATP binding. This IEA from UniProtKB keyword mapping confirms the same core function.
Reason: This is a duplicate annotation with the same GO term (GO:0005524) as the IBA annotation but with IEA evidence from UniProtKB keyword mapping. Duplicates with different evidence sources are acceptable and provide independent support. ATP binding is unambiguously a core function of MinD.
|
|
GO:0005886
plasma membrane
|
IEA
GO_REF:0000044 |
ACCEPT |
Summary: MinD associates with the plasma membrane. This is consistent with the more specific annotation GO:0009898 (cytoplasmic side of plasma membrane) which better captures the topology.
Reason: This annotation is correct - MinD is a peripheral membrane protein that associates with the plasma membrane via C-terminal amphipathic helices. While less specific than GO:0009898 (cytoplasmic side of plasma membrane), it is not incorrect. The IEA annotation from UniProtKB subcellular location mapping is acceptable alongside the more specific IBA annotation.
Supporting Evidence:
UniProt:Q01464
SUBCELLULAR LOCATION: Cell membrane; Peripheral membrane protein.
|
|
GO:0016887
ATP hydrolysis activity
|
IEA
GO_REF:0000002 |
ACCEPT |
Summary: Duplicate of the IBA annotation for ATP hydrolysis activity. This IEA from InterPro mapping provides independent support for this core enzymatic function.
Reason: This is a duplicate annotation with the same GO term (GO:0016887) as the IBA annotation but with IEA evidence from InterPro (IPR010223 MinD domain). Duplicates with different evidence sources are acceptable. ATP hydrolysis activity is well-established for MinD.
|
|
GO:0032506
cytokinetic process
|
IEA
GO_REF:0000117 |
ACCEPT |
Summary: MinD is involved in cytokinetic processes through its role in regulating division site selection and Z-ring positioning. This is a broad term that captures MinD's involvement in cell division.
Reason: MinD clearly functions in cytokinesis by regulating where cell division occurs. The MinCDJ system prevents polar division and promotes divisome disassembly. While this is a relatively broad term, it accurately reflects MinD's biological role. More specific annotations for negative regulation of FtsZ-dependent cytokinesis could be considered but this annotation is not incorrect.
Supporting Evidence:
PMID:20352045
the main function of the Min system is to prevent minicell formation adjacent to recently completed division sites by promoting the disassembly of the cytokinetic ring
|
|
GO:0051301
cell division
|
IEA
GO_REF:0000043 |
ACCEPT |
Summary: MinD is involved in cell division, specifically in regulating division site selection to ensure proper midcell septation. This broad term is accurate but non-specific.
Reason: MinD is clearly involved in cell division - it is a septum site-determining protein whose loss leads to minicell formation and cell division defects. This broad biological process annotation is accurate. More specific annotations exist (cytokinetic process, division septum site selection) but this does not make the broader annotation wrong.
Supporting Evidence:
UniProt:Q01464
RecName: Full=Septum site-determining protein MinD; AltName: Full=Cell division inhibitor MinD
|
|
GO:0005515
protein binding
|
IPI
PMID:25374563 Protein-tyrosine phosphorylation interaction network in Baci... |
KEEP AS NON CORE |
Summary: This annotation captures MinD's interaction with ywqD (PtkA, a tyrosine kinase; UniProtKB:P96716). The study shows MinD acts as a scaffold protein that tethers PtkA at the cell pole and can activate PtkA autophosphorylation in vitro. However, this is a secondary/moonlighting function rather than MinD's core evolved function.
Reason: The interaction between MinD and PtkA (ywqD) is documented by yeast two-hybrid, far-Western blotting, and in vivo localization studies in PMID:25374563. MinD acts as a platform protein that anchors PtkA at the cell pole and can activate PtkA autophosphorylation. However, this represents a secondary scaffolding function rather than MinD's core evolved function in division site selection. The generic 'protein binding' term also fails to capture the specific nature of this interaction. Consider modifying to a more informative term if available.
Supporting Evidence:
PMID:25374563
MinD could act as a platform protein that would tether PtkA at a specific cellular area. Additionally MinD would also act as an activator of PtkA for signal transmission to DivIVA.
PMID:25374563
Incubation of PtkA with increasing amounts of MinD activated its autophosphorylation, indicating that MinD is able to act as modulator of PtkA activity similar to TkmA
|
|
GO:0005515
protein binding
|
IPI
PMID:25374563 Protein-tyrosine phosphorylation interaction network in Baci... |
ACCEPT |
Summary: This annotation captures MinD's interaction with MinC (UniProtKB:Q01463). The MinD-MinC interaction is a CORE functional interaction - ATP-bound MinD dimers recruit MinC to the membrane where MinC acts as the direct inhibitor of FtsZ polymerization. This is the central mechanism of the Min system.
Reason: The MinD-MinC interaction is the core functional interaction of MinD. ATP-bound MinD dimers recruit MinC to form the MinCD inhibitory complex that blocks polar Z ring formation. This interaction is documented extensively in the literature and in IntAct (3 experiments). While 'protein binding' is a generic term, the annotation correctly captures a functionally critical interaction. UniProt explicitly documents the MinC interaction.
Supporting Evidence:
UniProt:Q01464
SUBUNIT: Interacts with MinC and FtsZ (By similarity). Interacts with MinJ.
UniProt:Q01464
INTERACTION: Q01464; Q01463: minC; NbExp=3; IntAct=EBI-6502875, EBI-9304968
PMID:20352045
MinD is a membrane-associated ATPase that sequesters MinC to the membrane interface, allowing it to interact with FtsZ
PMID:25374563
In this assay we detected the expected MinD-MinC complex
|
|
GO:0000918
division septum site selection
|
TAS
PMID:33849976 Dynamics of the Bacillus subtilis Min System. |
NEW |
Summary: MinD is directly involved in division septum site selection as part of the MinCDJ system. This is the core biological process function of MinD - ensuring that cell division occurs at midcell rather than at the poles.
Reason: This annotation is not currently in the GOA file but should be added. Division septum site selection (GO:0000918) precisely captures MinD's core biological role. The MinCDJ system functions to mark and enforce the midcell division site while preventing polar division. This term is more specific and accurate than the current 'division septum assembly' annotation.
Supporting Evidence:
UniProt:Q01464
RecName: Full=Septum site-determining protein MinD
file:BACSU/minD/minD-deep-research-falcon.md
MinD is a ParA/MinD-family Walker-type P-loop NTPase in Bacillus subtilis strain 168 that participates in the MinCDJ/DivIVA system for division-site selection
PMID:20352045
the main function of the Min system is to prevent minicell formation adjacent to recently completed division sites
|
|
GO:2000245
negative regulation of FtsZ-dependent cytokinesis
|
TAS
PMID:20352045 The MinCDJ system in Bacillus subtilis prevents minicell for... |
NEW |
Summary: MinD, through its recruitment of MinC, negatively regulates FtsZ-dependent cytokinesis at polar sites. MinC is the direct inhibitor of FtsZ polymerization, and MinD positions this inhibitor at poles and completed septa.
Reason: This term precisely captures MinD's role in preventing polar FtsZ ring formation. The MinCD complex blocks FtsZ polymerization at poles, preventing minicell formation. This is a core function of the Min system that should be annotated.
Supporting Evidence:
PMID:20352045
the main function of the Min system is to prevent minicell formation adjacent to recently completed division sites by promoting the disassembly of the cytokinetic ring
file:BACSU/minD/minD-deep-research-falcon.md
MinD recruits and activates MinC, the direct inhibitor of FtsZ polymerization, to suppress polar Z-ring formation
|
Q: What are the precise kinetic parameters of B. subtilis MinD membrane binding and ATPase activity under physiological conditions? Recent preprints provide in vitro measurements but physiological relevance needs confirmation.
Q: How does the MinD-PtkA interaction contribute to cell division regulation in vivo, and is DivIVA phosphorylation by PtkA functionally significant? PMID:25374563 shows MinD can scaffold and activate PtkA, which phosphorylates DivIVA, but biological significance is unclear.
Experiment: Quantitative live-cell imaging of MinD dynamics during the cell cycle using fluorescent protein fusions and single-molecule tracking to confirm gradient formation patterns in B. subtilis. This would validate the dynamic septal enrichment model proposed by recent studies and distinguish B. subtilis MinD behavior from E. coli oscillation.
Hypothesis: MinD's ATPase cycling drives the dynamic septal enrichment patterns observed in B. subtilis, distinct from the rapid pole-to-pole oscillation in E. coli.
Experiment: Site-directed mutagenesis of MinD ATP binding site residues combined with localization studies to confirm the role of ATPase cycling in membrane association patterns. This would provide direct evidence that ATPase activity drives MinD patterning as proposed by biochemical studies.
Hypothesis: ATPase activity is required for MinD patterning and membrane residence dynamics.
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gene_info: Name=minD; Synonyms=divIVB; OrderedLocusNames=BSU27990;
organism_full: Bacillus subtilis (strain 168).
protein_family: Belongs to the ParA family. MinD subfamily. .
protein_domains: CobQ/CobB/MinD/ParA_Nub-bd_dom. (IPR002586); MinD. (IPR010223);
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BEFORE YOU BEGIN RESEARCH: You MUST verify you are researching the CORRECT gene/protein. Gene symbols can be ambiguous, especially for less well-characterized genes from non-model organisms.
DO NOT PROCEED WITH RESEARCH ON A DIFFERENT GENE. Instead:
- State clearly: "The gene symbol 'minD' is ambiguous or literature is limited for this specific protein"
- Explain what you found (e.g., "Found extensive literature on a different gene with the same symbol in a different organism")
- Describe the protein based ONLY on the UniProt information provided above
- Suggest that the protein function can be inferred from domain/family information
Please provide a comprehensive research report on the gene minD (gene ID: minD, UniProt: Q01464) in BACSU.
The research report should be a detailed narrative explaining the function, biological processes, and localization of the gene product. Citations should be given for all claims.
You should prioritize authoritative reviews and primary scientific literature when conducting research. You can supplement
this with annotations you find in gene/protein databases, but these can be outdated or inaccurate.
We are specifically interested in the primary function of the gene - for enzymes, what reaction is catalyzed, and what is the substrate specificity? For transporters, what is the substrate? For structural proteins or adapters, what is the broader structural role? For signaling molecules, what is the role in the pathway.
We are interested in where in or outside the cell the gene product carries out its function.
We are also interested in the signaling or biochemical pathways in which the gene functions. We are less interested in broad pleiotropic effects, except where these elucidate the precise role.
Include evidence where possible. We are interested in both experimental evidence as well as inference from structure, evolution, or bioinformatic analysis. Precise studies should be prioritized over high-throughput, where available.
Question: You are an expert researcher providing comprehensive, well-cited information.
Provide detailed information focusing on:
1. Key concepts and definitions with current understanding
2. Recent developments and latest research (prioritize 2023-2024 sources)
3. Current applications and real-world implementations
4. Expert opinions and analysis from authoritative sources
5. Relevant statistics and data from recent studies
Format as a comprehensive research report with proper citations. Include URLs and publication dates where available.
Always prioritize recent, authoritative sources and provide specific citations for all major claims.
BEFORE YOU BEGIN RESEARCH: You MUST verify you are researching the CORRECT gene/protein. Gene symbols can be ambiguous, especially for less well-characterized genes from non-model organisms.
DO NOT PROCEED WITH RESEARCH ON A DIFFERENT GENE. Instead:
- State clearly: "The gene symbol 'minD' is ambiguous or literature is limited for this specific protein"
- Explain what you found (e.g., "Found extensive literature on a different gene with the same symbol in a different organism")
- Describe the protein based ONLY on the UniProt information provided above
- Suggest that the protein function can be inferred from domain/family information
Please provide a comprehensive research report on the gene minD (gene ID: minD, UniProt: Q01464) in BACSU.
The research report should be a detailed narrative explaining the function, biological processes, and localization of the gene product. Citations should be given for all claims.
You should prioritize authoritative reviews and primary scientific literature when conducting research. You can supplement
this with annotations you find in gene/protein databases, but these can be outdated or inaccurate.
We are specifically interested in the primary function of the gene - for enzymes, what reaction is catalyzed, and what is the substrate specificity? For transporters, what is the substrate? For structural proteins or adapters, what is the broader structural role? For signaling molecules, what is the role in the pathway.
We are interested in where in or outside the cell the gene product carries out its function.
We are also interested in the signaling or biochemical pathways in which the gene functions. We are less interested in broad pleiotropic effects, except where these elucidate the precise role.
Include evidence where possible. We are interested in both experimental evidence as well as inference from structure, evolution, or bioinformatic analysis. Precise studies should be prioritized over high-throughput, where available.
Plan status: We verified the target identity (Bacillus subtilis strain 168 MinD; UniProt Q01464) and gathered recent and authoritative sources. We then extracted mechanistic function, localization, interaction partners, mutant phenotypes, and 2024 updates, and created an artifact table summarizing key facts for embedding.
Artifact summary table
| Aspect | Finding (1-2 sentences) | Evidence (journal/source, year) | URL/DOI | Context ID(s) |
|---|---|---:|---|---|
| Identity / family / domains | MinD is a ParA/MinD-family Walker-type P-loop NTPase (ParA-like ATPase) in Bacillus subtilis strain 168, annotated with C-terminal membrane-targeting features. | mBio 2021 (review/experimental) | https://doi.org/10.1128/mbio.00296-21 | (feddersen2021dynamicsofthe pages 27-31) |
| ATPase function & membrane activation | MinD is an ATPase whose hydrolysis is strongly stimulated by membrane binding; reported kcat ~36.27 h^-1 in recent biochemical assays. | bioRxiv (Feddersen & Bramkamp), 2024 | https://doi.org/10.1101/2024.07.08.602513 | (feddersen2024mechanisticinsightsinto pages 1-6, feddersen2024mechanisticinsightsinto pages 27-30) |
| Oligomeric state (monomer/dimer) | MinD dimerizes in the ATP-bound state but both monomeric and dimeric species can bind membranes; ATPase cycle controls membrane residence and pattern formation. | bioRxiv 2024; bioRxiv (Bohorquez et al.) 2024 | https://doi.org/10.1101/2024.07.08.602513; https://doi.org/10.1101/2024.06.11.598461 | (feddersen2024mechanisticinsightsinto pages 1-6, bohorquez2025membraneaffinitydifference pages 1-5) |
| Membrane-targeting motifs (C-terminal amphipathic helices) | B. subtilis MinD contains two C-terminal amphipathic helices (MTS1 and MTSL) that mediate septal/polar membrane targeting; basic residues and helical structure are required. | Genes & Genetic Systems, 2017 (Ishikawa et al.) | https://doi.org/10.1266/ggs.16-00054 | (ishikawa2017septalmembranelocalization pages 1-2) |
| Interaction partners (MinC, MinJ, DivIVA) | MinD recruits MinC (the direct FtsZ inhibitor); MinJ acts as a membrane/transmembrane bridge linking MinD/MinC to DivIVA (DivIVA targets negatively curved membranes). | PLoS ONE 2010 (van Baarle & Bramkamp); mBio 2021 | https://doi.org/10.1371/journal.pone.0009850; https://doi.org/10.1128/mbio.00296-21 | (baarle2010themincdjsystem pages 1-2, feddersen2021dynamicsofthe pages 27-31) |
| Primary role in division-site selection & divisome disassembly | The MinCDJ system prevents polar Z-ring activity and promotes divisome disassembly after septation, thereby preventing minicell formation. | PLoS ONE 2010; mBio 2020 (Yu et al.) | https://doi.org/10.1371/journal.pone.0009850; https://doi.org/10.1128/mbio.03197-19 | (baarle2010themincdjsystem pages 1-2, feddersen2021dynamicsofthe pages 24-27) |
| Localization dynamics (poles, septa, clusters vs gradients) | In B. subtilis MinD enriches at poles and active division sites (septal enrichment) and can form dynamic clusters; the system shows polar-to-midcell gradients rather than rapid pole-to-pole oscillation. | mBio 2021; bioRxiv 2024 (Feddersen et al.) | https://doi.org/10.1128/mbio.00296-21; https://doi.org/10.1101/2024.07.08.602513 | (feddersen2021dynamicsofthe pages 27-31, feddersen2024mechanisticinsightsinto pages 1-6) |
| Mutant phenotypes (minD mutants) | minD loss or dysfunctional Min system produces minicells, persistent polar FtsZ rings (defective FtsZ recycling), altered cell length distributions, and changes in polar peptidoglycan remodeling. | mBio 2020 (Yu et al.); PLoS ONE 2010 | https://doi.org/10.1128/mbio.03197-19; https://doi.org/10.1371/journal.pone.0009850 | (feddersen2021dynamicsofthe pages 24-27, baarle2010themincdjsystem pages 1-2) |
| 2024 updates (diffusion vs affinity; comparable monomer/dimer affinity; septal enrichment) | Recent 2024 preprints propose that MinD patterning can be explained by membrane-binding/unbinding kinetics and differences in diffusion rather than large monomer/dimer membrane-affinity differences; they report comparable monomer/dimer membrane affinities and emphasize dynamic septal enrichment stabilized by MinJ/DivIVA. | bioRxiv (Bohorquez et al. 2024; Feddersen & Bramkamp 2024) | https://doi.org/10.1101/2024.06.11.598461; https://doi.org/10.1101/2024.07.08.602513 | (bohorquez2025membraneaffinitydifference pages 1-5, feddersen2024mechanisticinsightsinto pages 1-6) |
Table: A concise reference table summarizing biochemical function, localization, partners, mutant phenotypes, and 2024 updates for Bacillus subtilis MinD (UniProt Q01464), with primary evidence and DOIs for each claim.
1) Key concepts and definitions (verified identity, functions, pathways)
- Identity and family: MinD is a ParA/MinD-family Walker-type P-loop NTPase in Bacillus subtilis strain 168 that participates in the MinCDJ/DivIVA system for division-site selection (distinct from the E. coli MinCDE oscillator) (feddersen2021dynamicsofthe pages 27-31, feddersen2021dynamicsofthe pages 24-27).
- Core system architecture: DivIVA senses negative membrane curvature at poles and nascent septa, recruits the transmembrane scaffold MinJ, which in turn recruits MinC and MinD (MinCDJ). MinD recruits and activates MinC, the direct inhibitor of FtsZ polymerization, to suppress polar Z-ring formation and to promote disassembly of the divisome after septation (baarle2010themincdjsystem pages 1-2, feddersen2021dynamicsofthe pages 27-31).
- Localization paradigm in B. subtilis: Instead of pole-to-pole oscillation, the B. subtilis Min system forms polar and septal enrichments that can appear as a bipolar gradient from poles/new septa toward midcell, with dynamic recruitment to ongoing division sites (feddersen2021dynamicsofthe pages 27-31, feddersen2021dynamicsofthe pages 24-27).
URLs/dates: mBio review (Apr 2021): https://doi.org/10.1128/mbio.00296-21 (feddersen2021dynamicsofthe pages 27-31, feddersen2021dynamicsofthe pages 24-27). PLoS ONE (Mar 2010): https://doi.org/10.1371/journal.pone.0009850 (baarle2010themincdjsystem pages 1-2).
2) Biochemical function, domains, and mechanism
- ATPase activity and membrane activation: Recent biochemical assays show B. subtilis MinD ATPase activity is strongly stimulated by membrane binding, with kcat ≈ 36.27 h−1 in liposome assays; ATP binding accelerates detachment from membranes, indicating that membrane association/dissociation is coupled to the ATPase cycle (bio-layer interferometry and SMLM/SMT support). This suggests MinD does not require a MinE-like activator in B. subtilis (Jul 2024) (feddersen2024mechanisticinsightsinto pages 1-6, feddersen2024mechanisticinsightsinto pages 27-30). URL: https://doi.org/10.1101/2024.07.08.602513 (posted Jul 2024) (feddersen2024mechanisticinsightsinto pages 1-6, feddersen2024mechanisticinsightsinto pages 27-30).
- Oligomeric state and membrane binding: MinD dimerizes upon ATP binding and this dimer recruits MinC; notably, both monomeric and dimeric B. subtilis MinD can bind membranes, with measured release kinetics for specific mutants (e.g., K16A koff ≈ 2.77×10−3 s−1; D40A koff ≈ 1.76×10−3 s−1; G12V koff ≈ 47.8×10−3 s−1) (Jul 2024) (feddersen2024mechanisticinsightsinto pages 27-30). URL: https://doi.org/10.1101/2024.07.08.602513 (feddersen2024mechanisticinsightsinto pages 27-30).
- Membrane-targeting motifs: B. subtilis MinD possesses two C-terminal amphipathic α-helices, termed MTS1 and MTS-like (MTSL). Each helix can target nascent septal membranes independently in ΔminJ or ΔdivIVA cells; basic residues and intact helical structure are required for septal localization. Deleting both helices greatly reduces membrane targeting (Jun 2017) (ishikawa2017septalmembranelocalization pages 1-2). URL: https://doi.org/10.1266/ggs.16-00054 (ishikawa2017septalmembranelocalization pages 1-2).
3) Primary role in cell division and interaction network
- MinC recruitment and FtsZ inhibition: Dimerized MinD recruits MinC, which directly inhibits FtsZ polymer formation. In B. subtilis, MinJ bridges MinD/MinC to DivIVA’s curvature-sensing platform, thereby spatially restricting MinC action to poles/septa and preventing aberrant polar division (Apr 2021; Mar 2010) (feddersen2021dynamicsofthe pages 27-31, baarle2010themincdjsystem pages 1-2).
- Divisome disassembly: In vivo genetics and microscopy show that the MinCDJ system promotes disassembly of divisome components (FtsA, FtsL, PBP-2B) at completed division sites; in Min-deficient contexts, these components persist at old septa, predisposing to minicell formation (Mar 2010) (baarle2010themincdjsystem pages 1-2).
URLs/dates: mBio (Apr 2021): https://doi.org/10.1128/mbio.00296-21 (feddersen2021dynamicsofthe pages 27-31). PLoS ONE (Mar 2010): https://doi.org/10.1371/journal.pone.0009850 (baarle2010themincdjsystem pages 1-2).
4) Subcellular localization and dynamics
- Patterns in vivo: mBio imaging and modeling indicate that B. subtilis Min proteins dynamically enrich at active septa and poles rather than oscillate, leading to a time-resolved enrichment at the division site that subsequently seeds polar distributions in daughter cells (Apr 2021) (feddersen2021dynamicsofthe pages 27-31). URL: https://doi.org/10.1128/mbio.00296-21 (feddersen2021dynamicsofthe pages 27-31).
- Single-molecule insights: 2024 single-molecule localization/tracking shows wild-type MinD forms dynamic polar/septal patterns dependent on its ATPase cycle; a dimer-locked mutant (D40A) accumulates in larger, confined membrane clusters with a high immobile fraction (~54.2%), whereas monomeric variants bind the membrane more uniformly and lose patterning (Jul 2024) (feddersen2024mechanisticinsightsinto pages 27-30). URL: https://doi.org/10.1101/2024.07.08.602513 (feddersen2024mechanisticinsightsinto pages 27-30).
5) Mutant phenotypes and cellular consequences
- Minicells and elongation: Loss of MinD or Min system function produces elongated rods and anucleate minicells, reflecting failure to restrict polar division and/or to disassemble the divisome at old septa (Apr 2021; Mar 2010) (feddersen2021dynamicsofthe pages 24-27, baarle2010themincdjsystem pages 1-2).
- FtsZ recycling and cell size: Quantitative microfluidics plus fluorescence microscopy show that minD mutants fail to disassemble polar FtsZ rings, leading to defective recycling of FtsZ monomers, simultaneous maintenance of multiple Z-rings, and increased cell size despite similar division times (Apr 2020) (feddersen2021dynamicsofthe pages 24-27). URL: https://doi.org/10.1128/mbio.03197-19 (feddersen2021dynamicsofthe pages 24-27).
- Polar peptidoglycan remodeling: The Min system contributes to the inert nature of polar peptidoglycan; in minD mutants, polar PG becomes more remodelable, indicating a secondary role of the Min system in inhibiting polar cell wall turnover (Apr 2020) (feddersen2021dynamicsofthe pages 24-27). URL: https://doi.org/10.1128/mbio.03197-19 (feddersen2021dynamicsofthe pages 24-27).
6) Recent developments and latest research (2023–2024 priority)
- Membrane affinity versus diffusion model: A 2024 preprint argues that cyclical differences in membrane affinity between monomeric and dimeric MinD are not necessary to form the B. subtilis MinD gradient; instead, differences in diffusion rates and MinJ-mediated retention of dimers can explain observed distributions. Experimentally, monomeric and dimeric B. subtilis MinD exhibit comparable membrane affinities, and MinJ is not strictly required for MinD membrane association, although it stabilizes polar enrichment (bioRxiv Jun 2024) (bohorquez2025membraneaffinitydifference pages 1-5, bohorquez2025membraneaffinitydifference pages 47-49). URL: https://doi.org/10.1101/2024.06.11.598461 (bohorquez2025membraneaffinitydifference pages 1-5, bohorquez2025membraneaffinitydifference pages 47-49).
- Membrane-activated ATPase and patterning: Complementary 2024 work shows MinD’s ATPase is activated by membrane binding, with both monomer and dimer capable of membrane association. Pattern formation requires the ATPase-driven cycling that sets membrane residence times; mutants that disrupt this cycle (monomer-locked or dimer-locked) lose time-resolved gradients/patterns (bioRxiv Jul 2024) (feddersen2024mechanisticinsightsinto pages 1-6, feddersen2024mechanisticinsightsinto pages 27-30). URL: https://doi.org/10.1101/2024.07.08.602513 (feddersen2024mechanisticinsightsinto pages 1-6, feddersen2024mechanisticinsightsinto pages 27-30).
- Amphipathic helices and targeting: Earlier B. subtilis work showed two C-terminal amphipathic helices (MTS1 and MTSL) each can drive septal targeting independently, even in ΔminJ or ΔdivIVA backgrounds, highlighting intrinsic lipid-binding features of MinD distinct from E. coli’s single MTS paradigm (Jun 2017) (ishikawa2017septalmembranelocalization pages 1-2). URL: https://doi.org/10.1266/ggs.16-00054 (ishikawa2017septalmembranelocalization pages 1-2).
Interpretation: Together, 2024 studies refine the classical stationary-gradient view by emphasizing dynamic septal enrichment, membrane-activated ATPase cycling, comparable monomer/dimer membrane affinities, and a dominant role for diffusion and MinJ-mediated retention in shaping MinD distributions (bohorquez2025membraneaffinitydifference pages 1-5, feddersen2024mechanisticinsightsinto pages 1-6).
7) Current applications and real-world implementations
- Quantitative live-cell platforms: Microfluidic time-lapse fluorescence microscopy has been used to quantify growth, FtsZ dynamics, and MinD-dependent disassembly/recycling in B. subtilis, enabling precise phenotyping of minD mutants (Apr 2020) (feddersen2021dynamicsofthe pages 24-27). URL: https://doi.org/10.1128/mbio.03197-19 (feddersen2021dynamicsofthe pages 24-27).
- Single-molecule imaging and biophysics: Recent implementations include single-molecule localization microscopy and single-particle tracking, and bio-layer interferometry with liposomes, to quantify MinD membrane-binding kinetics and diffusion states in vivo and in vitro (Jul 2024) (feddersen2024mechanisticinsightsinto pages 1-6, feddersen2024mechanisticinsightsinto pages 27-30). URL: https://doi.org/10.1101/2024.07.08.602513 (feddersen2024mechanisticinsightsinto pages 1-6, feddersen2024mechanisticinsightsinto pages 27-30).
- Modeling frameworks: Particle-based kinetic Monte Carlo simulations incorporating measured diffusion, membrane residence, and MinJ retention successfully recapitulate MinD distributions, supporting a diffusion-dominant mechanism for gradient formation in B. subtilis (Jun 2024) (bohorquez2025membraneaffinitydifference pages 47-49). URL: https://doi.org/10.1101/2024.06.11.598461 (bohorquez2025membraneaffinitydifference pages 47-49).
8) Expert opinions and analysis from authoritative sources
- The 2021 mBio analysis emphasizes that, unlike E. coli, B. subtilis relies on a DivIVA–MinJ scaffold to localize MinCD to poles and nascent septa, with MinCDJ acting downstream of site selection to prevent re-initiation and to assist divisome disassembly, consistent with observed phenotypes and imaging (Apr 2021) (feddersen2021dynamicsofthe pages 27-31, feddersen2021dynamicsofthe pages 24-27). URL: https://doi.org/10.1128/mbio.00296-21 (feddersen2021dynamicsofthe pages 27-31, feddersen2021dynamicsofthe pages 24-27).
- The 2010 PLoS ONE study provides functional interpretation that MinCDJ’s principal role is to prevent minicells by promoting disassembly of the cytokinetic ring at recently completed septa—broadening the view beyond simple FtsZ polymer inhibition (Mar 2010) (baarle2010themincdjsystem pages 1-2). URL: https://doi.org/10.1371/journal.pone.0009850 (baarle2010themincdjsystem pages 1-2).
9) Relevant statistics and data (recent studies)
- ATPase kinetics: kcat ≈ 36.27 h−1 for membrane-activated B. subtilis MinD ATPase; ATP-dependent membrane release with koff values for mutants: K16A ≈ 2.77×10−3 s−1; D40A ≈ 1.76×10−3 s−1; G12V ≈ 47.8×10−3 s−1 (Jul 2024) (feddersen2024mechanisticinsightsinto pages 27-30). URL: https://doi.org/10.1101/2024.07.08.602513 (feddersen2024mechanisticinsightsinto pages 27-30).
- Single-molecule states: Representative diffusion-state fractions for MinD populations (WT example): fast ≈ 22.3% at D ≈ 0.60 μm2 s−1; slow ≈ 50.4% at D ≈ 0.084 μm2 s−1; confined ≈ 27.3% at D ≈ 0.020 μm2 s−1, with altered distributions in ATPase-cycle mutants (Jul 2024) (feddersen2024mechanisticinsightsinto pages 22-27). URL: https://doi.org/10.1101/2024.07.08.602513 (feddersen2024mechanisticinsightsinto pages 22-27).
- Imaging-based phenotypes: minD mutants show persistent polar FtsZ rings, multiple concurrent Z-rings constrained by FtsZ supply, increased cell size, and loss of polar cell-wall inertness (Apr 2020) (feddersen2021dynamicsofthe pages 24-27). URL: https://doi.org/10.1128/mbio.03197-19 (feddersen2021dynamicsofthe pages 24-27).
10) Mandatory verification
- Gene symbol and organism: All cited studies analyze MinD from Bacillus subtilis strain 168 or directly applicable lab strains; this matches UniProt Q01464 (minD/divIVB; BSU27990) (feddersen2021dynamicsofthe pages 27-31, feddersen2021dynamicsofthe pages 24-27, baarle2010themincdjsystem pages 1-2).
- Family/domains: Findings are consistent with ParA/MinD-family P-loop NTPases with membrane-targeting amphipathic helices; specific amphipathic helix evidence (MTS1/MTSL) is demonstrated in B. subtilis (ishikawa2017septalmembranelocalization pages 1-2). No cross-species symbol confusion was used to derive functional claims.
Conclusions
B. subtilis MinD (Q01464) is a membrane-associated, Walker-type ATPase whose ATPase cycle and C-terminal amphipathic helices drive membrane binding, turnover, and recruitment of MinC to suppress polar Z-ring assembly and to promote divisome disassembly at completed septa. Recent 2024 studies refine the model, showing that membrane binding alone activates MinD ATPase, both monomers and dimers can bind membranes with comparable affinities, and MinD patterning in B. subtilis is best explained by diffusion and MinJ-mediated retention rather than large monomer/dimer affinity cycles, while preserving the core role of MinD in septal/polar enrichment and FtsZ regulation (feddersen2024mechanisticinsightsinto pages 1-6, feddersen2024mechanisticinsightsinto pages 27-30, bohorquez2025membraneaffinitydifference pages 1-5, bohorquez2025membraneaffinitydifference pages 47-49, baarle2010themincdjsystem pages 1-2, feddersen2021dynamicsofthe pages 27-31, feddersen2021dynamicsofthe pages 24-27, ishikawa2017septalmembranelocalization pages 1-2).
References
(feddersen2021dynamicsofthe pages 27-31): Helge Feddersen, Laeschkir Würthner, Erwin Frey, and Marc Bramkamp. Dynamics of the bacillus subtilis min system. mBio, Apr 2021. URL: https://doi.org/10.1128/mbio.00296-21, doi:10.1128/mbio.00296-21. This article has 27 citations and is from a domain leading peer-reviewed journal.
(feddersen2024mechanisticinsightsinto pages 1-6): Helge Feddersen and Marc Bramkamp. Mechanistic insights into mind regulation and pattern formation in bacillus subtilis. bioRxiv, Jul 2024. URL: https://doi.org/10.1101/2024.07.08.602513, doi:10.1101/2024.07.08.602513. This article has 2 citations and is from a poor quality or predatory journal.
(feddersen2024mechanisticinsightsinto pages 27-30): Helge Feddersen and Marc Bramkamp. Mechanistic insights into mind regulation and pattern formation in bacillus subtilis. bioRxiv, Jul 2024. URL: https://doi.org/10.1101/2024.07.08.602513, doi:10.1101/2024.07.08.602513. This article has 2 citations and is from a poor quality or predatory journal.
(bohorquez2025membraneaffinitydifference pages 1-5): Laura C. Bohorquez, Henrik Strahl, Davide Marenduzzo, Martin J. Thiele, Frank Bürmann, and Leendert W. Hamoen. Cyclical mind membrane affinity differences are not necessary for mind gradient formation in bacillus subtilis. bioRxiv, Jun 2024. URL: https://doi.org/10.1101/2024.06.11.598461, doi:10.1101/2024.06.11.598461. This article has 3 citations and is from a poor quality or predatory journal.
(ishikawa2017septalmembranelocalization pages 1-2): Kazuki Ishikawa, Satoshi Matsuoka, Hiroshi Hara, and Kouji Matsumoto. Septal membrane localization by c-terminal amphipathic α-helices of mind in bacillus subtilis mutant cells lacking minj or diviva. Genes & genetic systems, 92 2:81-98, Jun 2017. URL: https://doi.org/10.1266/ggs.16-00054, doi:10.1266/ggs.16-00054. This article has 8 citations and is from a peer-reviewed journal.
(baarle2010themincdjsystem pages 1-2): Suey van Baarle and Marc Bramkamp. The mincdj system in bacillus subtilis prevents minicell formation by promoting divisome disassembly. PLoS ONE, 5:e9850, Mar 2010. URL: https://doi.org/10.1371/journal.pone.0009850, doi:10.1371/journal.pone.0009850. This article has 77 citations and is from a peer-reviewed journal.
(feddersen2021dynamicsofthe pages 24-27): Helge Feddersen, Laeschkir Würthner, Erwin Frey, and Marc Bramkamp. Dynamics of the bacillus subtilis min system. mBio, Apr 2021. URL: https://doi.org/10.1128/mbio.00296-21, doi:10.1128/mbio.00296-21. This article has 27 citations and is from a domain leading peer-reviewed journal.
(bohorquez2025membraneaffinitydifference pages 47-49): Laura C. Bohorquez, Henrik Strahl, Davide Marenduzzo, Martin J. Thiele, Frank Bürmann, and Leendert W. Hamoen. Cyclical mind membrane affinity differences are not necessary for mind gradient formation in bacillus subtilis. bioRxiv, Jun 2024. URL: https://doi.org/10.1101/2024.06.11.598461, doi:10.1101/2024.06.11.598461. This article has 3 citations and is from a poor quality or predatory journal.
(feddersen2024mechanisticinsightsinto pages 22-27): Helge Feddersen and Marc Bramkamp. Mechanistic insights into mind regulation and pattern formation in bacillus subtilis. bioRxiv, Jul 2024. URL: https://doi.org/10.1101/2024.07.08.602513, doi:10.1101/2024.07.08.602513. This article has 2 citations and is from a poor quality or predatory journal.
id: Q01464
gene_symbol: minD
product_type: PROTEIN
status: IN_PROGRESS
taxon:
id: NCBITaxon:224308
label: Bacillus subtilis (strain 168)
description: >-
MinD is a septum site-determining protein and ParA-family Walker-type ATPase
essential for correct placement of the bacterial cell division site. MinD acts
in concert with MinC to form an inhibitory complex that blocks polar Z ring
formation, preventing aberrant division at cell poles. The ATP-bound form of
MinD dimerizes and recruits MinC to the membrane, where MinC directly inhibits
FtsZ polymerization. Unlike E. coli, B. subtilis lacks MinE and instead uses
MinJ as the topological determinant that bridges MinD/MinC to DivIVA, which
senses negative membrane curvature at poles and septa. MinD's ATPase cycle
controls membrane residence time and drives dynamic polar/septal enrichment
patterns that prevent polar septum formation and promote divisome disassembly
after cytokinesis. Loss of MinD leads to minicell formation due to aberrant
polar division.
existing_annotations:
- term:
id: GO:0005524
label: ATP binding
evidence_type: IBA
original_reference_id: GO_REF:0000033
review:
summary: >-
MinD is a ParA-family Walker-type ATPase with a well-characterized ATP
binding site at residues 11-18 (P-loop motif). ATP binding is essential for
MinD function and drives dimerization, which is required for MinC recruitment
and membrane association. This is a core molecular function supported by
extensive phylogenetic and biochemical evidence.
action: ACCEPT
reason: >-
ATP binding is a core molecular function of MinD. The protein contains a
characteristic P-loop NTPase domain (InterPro: IPR027417) with an ATP binding
site at residues 11-18 documented in UniProt. The IBA annotation is
well-supported by phylogenetic inference and aligns with the conserved function
across MinD family proteins. Biochemical studies confirm ATP binding is
essential for MinD dimerization and function.
supported_by:
- reference_id: UniProt:Q01464
supporting_text: "BINDING 11..18 /ligand=\"ATP\" /ligand_id=\"ChEBI:CHEBI:30616\""
- reference_id: file:BACSU/minD/minD-deep-research-falcon.md
supporting_text: "MinD is an ATPase whose hydrolysis is strongly stimulated by membrane binding"
- term:
id: GO:0016887
label: ATP hydrolysis activity
evidence_type: IBA
original_reference_id: GO_REF:0000033
review:
summary: >-
MinD possesses intrinsic ATP hydrolysis activity that is membrane-activated.
Recent biochemical studies report kcat of approximately 36.27 h^-1 in liposome
assays. The ATPase cycle controls membrane residence time and is essential for
MinD patterning and function in division site selection.
action: ACCEPT
reason: >-
ATP hydrolysis is a core enzymatic function of MinD essential for its role in
division site selection. Unlike E. coli MinD which requires MinE for stimulation,
B. subtilis MinD ATPase is activated by membrane binding alone. The ATPase cycle
drives the dynamic membrane association/dissociation that creates the spatial
gradients necessary for correct division site positioning. This IBA annotation is
strongly supported by phylogenetic inference and recent biochemical characterization.
supported_by:
- reference_id: file:BACSU/minD/minD-deep-research-falcon.md
supporting_text: "MinD ATPase activity is strongly stimulated by membrane binding, with kcat approximately 36.27 h^-1 in liposome assays"
- reference_id: PMID:33849976
supporting_text: "MinD, a protein that belongs to the WACA (Walker A cytomotive ATPase) family"
- term:
id: GO:0005829
label: cytosol
evidence_type: IBA
original_reference_id: GO_REF:0000033
review:
summary: >-
MinD is found in the cytosol as part of its dynamic cycling between cytoplasm
and membrane. The ATP-free monomeric form of MinD is predominantly cytosolic,
while ATP-bound dimeric MinD associates with the membrane. This dynamic
localization is essential for MinD function.
action: ACCEPT
reason: >-
MinD cycles between cytosol and membrane as part of its functional mechanism.
Single-molecule tracking studies show that MinD exists in multiple diffusion
states including a fast cytosolic fraction (D approximately 0.60 um^2/s). The
cytosolic pool represents the ATP-free/monomeric form that is part of the
functional cycle. This annotation correctly captures one aspect of MinD's
dynamic localization.
supported_by:
- reference_id: file:BACSU/minD/minD-deep-research-falcon.md
supporting_text: "Representative diffusion-state fractions for MinD populations (WT example): fast approximately 22.3% at D approximately 0.60 um^2 s^-1"
- term:
id: GO:0009898
label: cytoplasmic side of plasma membrane
evidence_type: IBA
original_reference_id: GO_REF:0000033
review:
summary: >-
MinD localizes to the cytoplasmic side of the plasma membrane via two C-terminal
amphipathic helices (MTS1 and MTSL). Membrane association is enhanced in the
ATP-bound dimeric state and is essential for recruiting MinC to inhibit polar
FtsZ ring formation. MinD enriches at poles and active division sites.
action: ACCEPT
reason: >-
Membrane localization is a core aspect of MinD function. B. subtilis MinD
possesses two C-terminal amphipathic alpha-helices (MTS1 and MTSL) that mediate
membrane targeting. Unlike E. coli MinD which oscillates rapidly pole-to-pole,
B. subtilis MinD forms polar and septal enrichments with dynamic recruitment to
division sites. UniProt annotates MinD as a peripheral membrane protein
associated with the cell membrane.
supported_by:
- reference_id: UniProt:Q01464
supporting_text: "SUBCELLULAR LOCATION: Cell membrane; Peripheral membrane protein."
- reference_id: PMID:28674273
supporting_text: "Bacillus subtilis MinD has two amphipathic α-helices rich in basic amino acid residues at its C-terminus"
- reference_id: file:BACSU/minD/minD-deep-research-falcon.md
supporting_text: "In B. subtilis MinD enriches at poles and active division sites (septal enrichment)"
- term:
id: GO:0000166
label: nucleotide binding
evidence_type: IEA
original_reference_id: GO_REF:0000043
review:
summary: >-
This is a parent term of GO:0005524 (ATP binding). MinD specifically binds ATP
through its P-loop motif. The more specific ATP binding annotation already
captures the core function.
action: ACCEPT
reason: >-
This IEA annotation from UniProtKB keyword mapping is correct but less specific
than the ATP binding (GO:0005524) annotation already present via IBA evidence.
Since MinD is specifically an ATP-binding ATPase, this broader term is
technically accurate but redundant with the more informative ATP binding
annotation. Acceptable to retain as it does not contradict other annotations.
- term:
id: GO:0000917
label: division septum assembly
evidence_type: IEA
original_reference_id: GO_REF:0000043
review:
summary: >-
MinD is involved in the regulation of division septum assembly, specifically
by preventing inappropriate polar septum formation and promoting divisome
disassembly after cytokinesis. However, MinD's role is inhibitory/regulatory
rather than directly assembling the septum.
action: MODIFY
reason: >-
While MinD is clearly involved in division septum-related processes, the term
'division septum assembly' (GO:0000917) implies direct participation in building
the septum. MinD's actual role is to NEGATIVELY regulate septum formation at
inappropriate sites (cell poles) and to promote disassembly of the divisome
after septation. More appropriate terms would be 'regulation of division septum
assembly' (GO:0032955) or 'negative regulation of division septum assembly'
(GO:0010974), or 'division septum site selection' (GO:0000918). The MinCDJ
system prevents polar Z-ring activity and promotes divisome disassembly.
proposed_replacement_terms:
- id: GO:0000918
label: division septum site selection
- id: GO:0032955
label: regulation of division septum assembly
supported_by:
- reference_id: PMID:20352045
supporting_text: "the main function of the Min system is to prevent minicell formation adjacent to recently completed division sites by promoting the disassembly of the cytokinetic ring"
- reference_id: file:BACSU/minD/minD-deep-research-falcon.md
supporting_text: "MinCDJ acting downstream of site selection to prevent re-initiation and to assist divisome disassembly"
- term:
id: GO:0005524
label: ATP binding
evidence_type: IEA
original_reference_id: GO_REF:0000043
review:
summary: >-
Duplicate of the IBA annotation for ATP binding. This IEA from UniProtKB
keyword mapping confirms the same core function.
action: ACCEPT
reason: >-
This is a duplicate annotation with the same GO term (GO:0005524) as the IBA
annotation but with IEA evidence from UniProtKB keyword mapping. Duplicates
with different evidence sources are acceptable and provide independent support.
ATP binding is unambiguously a core function of MinD.
- term:
id: GO:0005886
label: plasma membrane
evidence_type: IEA
original_reference_id: GO_REF:0000044
review:
summary: >-
MinD associates with the plasma membrane. This is consistent with the more
specific annotation GO:0009898 (cytoplasmic side of plasma membrane) which
better captures the topology.
action: ACCEPT
reason: >-
This annotation is correct - MinD is a peripheral membrane protein that
associates with the plasma membrane via C-terminal amphipathic helices.
While less specific than GO:0009898 (cytoplasmic side of plasma membrane),
it is not incorrect. The IEA annotation from UniProtKB subcellular location
mapping is acceptable alongside the more specific IBA annotation.
supported_by:
- reference_id: UniProt:Q01464
supporting_text: "SUBCELLULAR LOCATION: Cell membrane; Peripheral membrane protein."
- term:
id: GO:0016887
label: ATP hydrolysis activity
evidence_type: IEA
original_reference_id: GO_REF:0000002
review:
summary: >-
Duplicate of the IBA annotation for ATP hydrolysis activity. This IEA from
InterPro mapping provides independent support for this core enzymatic function.
action: ACCEPT
reason: >-
This is a duplicate annotation with the same GO term (GO:0016887) as the IBA
annotation but with IEA evidence from InterPro (IPR010223 MinD domain).
Duplicates with different evidence sources are acceptable. ATP hydrolysis
activity is well-established for MinD.
- term:
id: GO:0032506
label: cytokinetic process
evidence_type: IEA
original_reference_id: GO_REF:0000117
review:
summary: >-
MinD is involved in cytokinetic processes through its role in regulating
division site selection and Z-ring positioning. This is a broad term that
captures MinD's involvement in cell division.
action: ACCEPT
reason: >-
MinD clearly functions in cytokinesis by regulating where cell division
occurs. The MinCDJ system prevents polar division and promotes divisome
disassembly. While this is a relatively broad term, it accurately reflects
MinD's biological role. More specific annotations for negative regulation
of FtsZ-dependent cytokinesis could be considered but this annotation is
not incorrect.
supported_by:
- reference_id: PMID:20352045
supporting_text: "the main function of the Min system is to prevent minicell formation adjacent to recently completed division sites by promoting the disassembly of the cytokinetic ring"
- term:
id: GO:0051301
label: cell division
evidence_type: IEA
original_reference_id: GO_REF:0000043
review:
summary: >-
MinD is involved in cell division, specifically in regulating division site
selection to ensure proper midcell septation. This broad term is accurate
but non-specific.
action: ACCEPT
reason: >-
MinD is clearly involved in cell division - it is a septum site-determining
protein whose loss leads to minicell formation and cell division defects.
This broad biological process annotation is accurate. More specific annotations
exist (cytokinetic process, division septum site selection) but this does not
make the broader annotation wrong.
supported_by:
- reference_id: UniProt:Q01464
supporting_text: "RecName: Full=Septum site-determining protein MinD; AltName: Full=Cell division inhibitor MinD"
- term:
id: GO:0005515
label: protein binding
evidence_type: IPI
original_reference_id: PMID:25374563
review:
summary: >-
This annotation captures MinD's interaction with ywqD (PtkA, a tyrosine kinase;
UniProtKB:P96716). The study shows MinD acts as a scaffold protein that tethers
PtkA at the cell pole and can activate PtkA autophosphorylation in vitro.
However, this is a secondary/moonlighting function rather than MinD's core
evolved function.
action: KEEP_AS_NON_CORE
reason: >-
The interaction between MinD and PtkA (ywqD) is documented by yeast two-hybrid,
far-Western blotting, and in vivo localization studies in PMID:25374563. MinD
acts as a platform protein that anchors PtkA at the cell pole and can activate
PtkA autophosphorylation. However, this represents a secondary scaffolding
function rather than MinD's core evolved function in division site selection.
The generic 'protein binding' term also fails to capture the specific nature
of this interaction. Consider modifying to a more informative term if available.
additional_reference_ids:
- PMID:25374563
supported_by:
- reference_id: PMID:25374563
supporting_text: "MinD could act as a platform protein that would tether PtkA at a specific cellular area. Additionally MinD would also act as an activator of PtkA for signal transmission to DivIVA."
- reference_id: PMID:25374563
supporting_text: "Incubation of PtkA with increasing amounts of MinD activated its autophosphorylation, indicating that MinD is able to act as modulator of PtkA activity similar to TkmA"
- term:
id: GO:0005515
label: protein binding
evidence_type: IPI
original_reference_id: PMID:25374563
review:
summary: >-
This annotation captures MinD's interaction with MinC (UniProtKB:Q01463). The
MinD-MinC interaction is a CORE functional interaction - ATP-bound MinD dimers
recruit MinC to the membrane where MinC acts as the direct inhibitor of FtsZ
polymerization. This is the central mechanism of the Min system.
action: ACCEPT
reason: >-
The MinD-MinC interaction is the core functional interaction of MinD.
ATP-bound MinD dimers recruit MinC to form the MinCD inhibitory complex that
blocks polar Z ring formation. This interaction is documented extensively in
the literature and in IntAct (3 experiments). While 'protein binding' is a
generic term, the annotation correctly captures a functionally critical
interaction. UniProt explicitly documents the MinC interaction.
supported_by:
- reference_id: UniProt:Q01464
supporting_text: "SUBUNIT: Interacts with MinC and FtsZ (By similarity). Interacts with MinJ."
- reference_id: UniProt:Q01464
supporting_text: "INTERACTION: Q01464; Q01463: minC; NbExp=3; IntAct=EBI-6502875, EBI-9304968"
- reference_id: PMID:20352045
supporting_text: "MinD is a membrane-associated ATPase that sequesters MinC to the membrane interface, allowing it to interact with FtsZ"
- reference_id: PMID:25374563
supporting_text: "In this assay we detected the expected MinD-MinC complex"
# Additional annotation that should be considered based on literature
- term:
id: GO:0000918
label: division septum site selection
evidence_type: TAS
original_reference_id: PMID:33849976
review:
summary: >-
MinD is directly involved in division septum site selection as part of the
MinCDJ system. This is the core biological process function of MinD - ensuring
that cell division occurs at midcell rather than at the poles.
action: NEW
reason: >-
This annotation is not currently in the GOA file but should be added. Division
septum site selection (GO:0000918) precisely captures MinD's core biological
role. The MinCDJ system functions to mark and enforce the midcell division
site while preventing polar division. This term is more specific and accurate
than the current 'division septum assembly' annotation.
supported_by:
- reference_id: UniProt:Q01464
supporting_text: "RecName: Full=Septum site-determining protein MinD"
- reference_id: file:BACSU/minD/minD-deep-research-falcon.md
supporting_text: "MinD is a ParA/MinD-family Walker-type P-loop NTPase in Bacillus subtilis strain 168 that participates in the MinCDJ/DivIVA system for division-site selection"
- reference_id: PMID:20352045
supporting_text: "the main function of the Min system is to prevent minicell formation adjacent to recently completed division sites"
- term:
id: GO:2000245
label: negative regulation of FtsZ-dependent cytokinesis
evidence_type: TAS
original_reference_id: PMID:20352045
review:
summary: >-
MinD, through its recruitment of MinC, negatively regulates FtsZ-dependent
cytokinesis at polar sites. MinC is the direct inhibitor of FtsZ polymerization,
and MinD positions this inhibitor at poles and completed septa.
action: NEW
reason: >-
This term precisely captures MinD's role in preventing polar FtsZ ring
formation. The MinCD complex blocks FtsZ polymerization at poles, preventing
minicell formation. This is a core function of the Min system that should
be annotated.
supported_by:
- reference_id: PMID:20352045
supporting_text: "the main function of the Min system is to prevent minicell formation adjacent to recently completed division sites by promoting the disassembly of the cytokinetic ring"
- reference_id: file:BACSU/minD/minD-deep-research-falcon.md
supporting_text: "MinD recruits and activates MinC, the direct inhibitor of FtsZ polymerization, to suppress polar Z-ring formation"
references:
- id: GO_REF:0000002
title: Gene Ontology annotation through association of InterPro records with GO terms
findings: []
- id: GO_REF:0000033
title: Annotation inferences using phylogenetic trees
findings: []
- id: GO_REF:0000043
title: Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping
findings: []
- id: GO_REF:0000044
title: Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping
findings: []
- id: GO_REF:0000117
title: Electronic Gene Ontology annotations created by ARBA machine learning models
findings: []
- id: PMID:25374563
title: Protein-tyrosine phosphorylation interaction network in Bacillus subtilis reveals new substrates, kinase activators and kinase cross-talk
findings:
- statement: MinD interacts with tyrosine kinase PtkA (ywqD) and acts as a scaffold protein anchoring PtkA at the cell pole
supporting_text: "MinD could act as a platform protein that would tether PtkA at a specific cellular area"
- statement: MinD can activate PtkA autophosphorylation in vitro but less efficiently than TkmA
supporting_text: "Incubation of PtkA with increasing amounts of MinD activated its autophosphorylation"
- statement: MinD is structurally homologous to BY-kinases but lacks kinase activity
supporting_text: "MinD is an ATPase from the P-loop NTPase superfamily previously reported to be a close structural homolog of BY-kinases, but lacking the C-terminal tyrosine cluster necessary for kinase autophosphorylation"
- id: PMID:20352045
title: The MinCDJ system in Bacillus subtilis prevents minicell formation by promoting divisome disassembly.
findings:
- statement: The B. subtilis MinCDJ system prevents polar division and promotes divisome disassembly after septation
supporting_text: "the main function of the Min system is to prevent minicell formation adjacent to recently completed division sites by promoting the disassembly of the cytokinetic ring"
- statement: MinJ acts as bridge linking MinD/MinC to DivIVA
supporting_text: "a new component of the B. subtilis Min system was identified, MinJ, which acts as a bridge between DivIVA and MinCD"
- id: PMID:33849976
title: Dynamics of the Bacillus subtilis Min System.
findings:
- statement: MinD forms polar and septal enrichments rather than rapid pole-to-pole oscillation in B. subtilis
supporting_text: "the Min system of B. subtilis localizes dynamically to active sites of division, often organized in clusters"
- statement: DivIVA senses negative membrane curvature and recruits MinJ which recruits MinC/MinD
supporting_text: "MinJ acts as a molecular bridge between MinD and DivIVA"
- id: PMID:28674273
title: Septal membrane localization by C-terminal amphipathic α-helices of MinD in Bacillus subtilis mutant cells lacking MinJ or DivIVA.
findings:
- statement: B. subtilis MinD has two C-terminal amphipathic helices (MTS1 and MTSL) for membrane targeting
supporting_text: "Bacillus subtilis MinD has two amphipathic α-helices rich in basic amino acid residues at its C-terminus"
- id: PMID:18976281
title: MinJ (YvjD) is a topological determinant of cell division in Bacillus subtilis.
findings:
- statement: MinD interacts with MinJ in B. subtilis
supporting_text: "MinJ restricted MinD activity by localizing MinD to the cell poles through direct protein-protein interaction"
- id: PMID:19019154
title: A novel component of the division-site selection system of Bacillus subtilis and a new mode of action for the division inhibitor MinCD
findings:
- statement: MinD interacts with MinJ as part of the division-site selection system
supporting_text: "a novel component of the division-site selection system of Bacillus subtilis"
core_functions:
- description: >-
MinD is a ParA-family ATPase that determines bacterial cell division site
by recruiting MinC to membrane surfaces, forming the MinCD complex that
inhibits polar FtsZ ring formation. This is the core evolved function of MinD
in B. subtilis, ensuring that cell division occurs at midcell rather than at
the cell poles. The ATPase cycle controls membrane residence time and drives
dynamic polar/septal enrichment patterns.
molecular_function:
id: GO:0016887
label: ATP hydrolysis activity
directly_involved_in:
- id: GO:0000918
label: division septum site selection
- id: GO:2000245
label: negative regulation of FtsZ-dependent cytokinesis
locations:
- id: GO:0009898
label: cytoplasmic side of plasma membrane
supported_by:
- reference_id: PMID:33849976
supporting_text: "MinD, a protein that belongs to the WACA (Walker A cytomotive ATPase) family"
- reference_id: PMID:20352045
supporting_text: "MinD is a membrane-associated ATPase that sequesters MinC to the membrane interface, allowing it to interact with FtsZ"
- reference_id: PMID:20352045
supporting_text: "the main function of the Min system is to prevent minicell formation adjacent to recently completed division sites by promoting the disassembly of the cytokinetic ring"
suggested_questions:
- question: >-
What are the precise kinetic parameters of B. subtilis MinD membrane binding
and ATPase activity under physiological conditions? Recent preprints provide
in vitro measurements but physiological relevance needs confirmation.
- question: >-
How does the MinD-PtkA interaction contribute to cell division regulation
in vivo, and is DivIVA phosphorylation by PtkA functionally significant?
PMID:25374563 shows MinD can scaffold and activate PtkA, which phosphorylates
DivIVA, but biological significance is unclear.
suggested_experiments:
- hypothesis: >-
MinD's ATPase cycling drives the dynamic septal enrichment patterns observed
in B. subtilis, distinct from the rapid pole-to-pole oscillation in E. coli.
description: >-
Quantitative live-cell imaging of MinD dynamics during the cell cycle using
fluorescent protein fusions and single-molecule tracking to confirm gradient
formation patterns in B. subtilis. This would validate the dynamic septal
enrichment model proposed by recent studies and distinguish B. subtilis MinD
behavior from E. coli oscillation.
- hypothesis: >-
ATPase activity is required for MinD patterning and membrane residence dynamics.
description: >-
Site-directed mutagenesis of MinD ATP binding site residues combined with
localization studies to confirm the role of ATPase cycling in membrane
association patterns. This would provide direct evidence that ATPase activity
drives MinD patterning as proposed by biochemical studies.