division septum

GO:0000935 · Envelope · Envelope layer · Proposed

A cell septum which forms as part of the division site and functions in the compartmentalization of a cell into two daughter cells at division. A division septum spans a cell and does not allow exchange of organelles or cytoplasm between compartments. [GO:0000935]

Synonyms: complete septum; cell septum surface

Part of: GO:0032153 — cell division site (no local record)

UniProt location names: UniProt Consortium, CC BY 4.0. Reference label and route sources.

Components

Component	Type	Part of / acts on	Grounding	Genes	Stoichiometry	Essential	Role
bacterial septal peptidoglycan	Peptidoglycan	part of	Reviewed label only (reviewed name; no accession asserted)			CONDITIONAL	Newly synthesized peptidoglycan that closes the division plane in walled bacteria. `DOI:10.1111/j.1749-6632.2012.06818.x` Egan and Vollmer 2012 review septal peptidoglycan synthesis as the peptidoglycan-building output of the bacterial divisome. `DOI:10.1146/annurev-biophys-121219-081703` McQuillen and Xiao 2020 review how the FtsZ ring organizes septal peptidoglycan synthesis.

Taxonomic distribution

NCBITaxon:2 Bacteria — COMMON: Walled FtsZ-dividing bacteria close the division plane with septal peptidoglycan, while wall-less lineages and bacteria using other division modes are outside this broad row. [DOI:10.1146/annurev-biophys-121219-081703]

Canonical examples

NCBITaxon:83333 Escherichia coli K-12 — Rod-shaped diderm model for divisome-directed septal peptidoglycan synthesis. [DOI:10.1146/annurev-biophys-121219-081703]
NCBITaxon:1423 Bacillus subtilis — Gram-positive model for FtsZ-guided septal synthesis and division-plane closure. [DOI:10.1146/annurev-biophys-121219-081703]

Functions

daughter-cell compartmentalization — The completed division septum spans the division site and blocks cytoplasmic and organellar exchange between nascent daughter cells.
- GO:0000935 GO:0000935 defines the division septum as a cell septum that compartmentalizes two daughter cells.

Mechanism graphs

The divisome builds a closing septal cross-wall (ASSEMBLY)

At the cell division site, FtsZ-guided septal synthases polymerize new peptidoglycan into a cross-wall; when this septal layer spans the division plane it compartmentalizes the two nascent daughter cells.

Subject	Predicate	Object	Evidence
divisome complex	localizes to	cell division site	`GO:1990586` GO:1990586 defines the divisome as the complex that carries out division septum assembly at the division site.
divisome complex	synthesizes	bacterial septal peptidoglycan	`DOI:10.1146/annurev-biophys-121219-081703` McQuillen and Xiao 2020 review FtsZ-guided motion of septal peptidoglycan synthases. `DOI:10.1111/j.1749-6632.2012.06818.x` Egan and Vollmer 2012 describe septal synthesis as the output of the division machinery.
bacterial septal peptidoglycan	forms	division septum	`GO:0030428` GO:0030428 defines cell septa as wall structures composed of peptidoglycan and/or chitin that grow inward from the cell wall.
division septum	compartmentalizes	daughter-cell compartments	`GO:0000935` GO:0000935 defines the division septum by daughter-cell compartmentalization.

Discussions

INTERPRETATION (RESOLVED): Keep the division septum record scoped to the septal cross-wall rather than merging it with the divisome complex. GO:0000935 denotes the physical septum that spans the cell, whereas GO:1990586 denotes the protein machine that builds septal wall material at the division site.
CURATION_TODO (OPEN): Add chitin, glucan, or other non-peptidoglycan constituents when the generic division septum record is expanded beyond bacterial examples. GO:0000935 denotes a generic division septum and GO:0030428 covers peptidoglycan- and chitin-containing cell septa. This pass only read bacterial divisome and peptidoglycan literature, so fungal septal wall constituents need their own evidence before being modeled.

Evidence

GO:0000935 Gene Ontology cellular-component term for the division septum.
GO:0030428 Gene Ontology cellular-component term for the broader cell septum class.
GO:0032153 — cell division site Gene Ontology cellular-component term for the cell division site that contains division septum structures.
DOI:10.1146/annurev-biophys-121219-081703 McQuillen and Xiao 2020, Insights into the Structure, Function, and Dynamics of the Bacterial Cytokinetic FtsZ-Ring, Annual Review of Biophysics.
DOI:10.1111/j.1749-6632.2012.06818.x Egan and Vollmer 2012, The physiology of bacterial cell division, Annals of the New York Academy of Sciences.

Curation history

2026-09-22T15:10:43Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-22T15:12:34Z codex · EXPANDED_RECORD — Added GO synonymy, cell-septum parentage, division-site parthood, septal-peptidoglycan composition, bacterial distribution, E. coli and B. subtilis examples, barrier and division-plane-closure functions, GO/DOI evidence, a nonmechanistic divisome-to-septum assembly graph, and a resolved divisome/product boundary discussion.
2026-09-22T15:25:12Z codex · ADDRESSED_PR_REVIEW — Resolved PR #1292 review issues #1293, #1294 and #1295 by removing the assembly-only division-plane-closure function, narrowing the peptidoglycan component to bacterial septal peptidoglycan with conditional essentiality and a fungal polymer TODO, and retyping the divisome and daughter-compartment graph nodes.

Source: data/structures/envelope/division_septum.yaml