Plastid division by the FtsZ and ARC5 rings

Plastids divide by binary fission with a machinery built from both of their ancestries. Inside, the bacterium-derived tubulin-like GTPases FtsZ1 and FtsZ2 form the Z ring in the stroma, anchored to the inner envelope; outside, the host-derived dynamin-related GTPase ARC5 assembles on the cytosolic face and constricts the outer envelope. The Min system, inherited from bacteria, keeps the ring at the midpoint. This module is the green-lineage core of plastid division.

MODULE:plastid_divisionDRAFTCONCRETEBiological Processmodules/plastid_division.yaml

plastid fissionGO:0043572 chloroplast fissionGO:0010020

Viridiplantae scope, with Arabidopsis representatives; PAINT places chloroplast fission at Viridiplantae on the FtsZ1 and FtsZ2 nodes (PTN000768282, PTN000768287). Read as a satisfiability rule, a genome needs FtsZ1, FtsZ2, ARC6 and ARC5; MinD and PDV1/PDV2 are optional. The FtsZ2 node records as lost the bacterial cell-division terms (IRD at PTN000768287). The FtsZ1 (SF12), FtsZ2 (SF16), ARC6 (SF1) and ARC5 (SF78) selectors list Arabidopsis members only, so other green lineages may fail the required steps for want of a selector; the optional MinD selector, by contrast, also matches bacterial MinD. Not modelled: PARC6 (CDP1, Q8VY16, the ARC6 paralogue in PTHR33925:SF2, which is local) and the other ring regulators, and the outer plastid-dividing (PD) ring.

6Nodes

5Parts

0Variant Sets

0Variants

6Annotons

5Connections

Derived QC

Recommended-field compliance

100.0% recommended fields populated

All recommended fields populated.

Module deep research

✗ none found

No MODULE:plastid_division deep-research report alongside the module YAML.

Leaf nodes lacking representative members

✓ every leaf node grounds to a representative protein.

Template conformance

✓ every declared conforms_to bundle matches its template motif.

Function consistency and core coverage

0 gene-function check(s) reflected in core functions · 0 conflict(s) · 12 evidence or coverage gap(s) (12 comparison(s))

Retained noncore functions are reported separately; they do not require promotion to core functions. Support from representative genes does not establish conservation across the whole family. Missing reviews or identifiers leave a claim unverified.

Annoton	Participant	Function	Assessment
mind_positioning	MIND1 (Arabidopsis) UniProtKB:Q9MBA2 Family Representative	ATP hydrolysis activity GO:0016887	Review Missing No ai-review exists for this protein; its function and core-function coverage cannot yet be checked.
ftsz1	FTSZ1 (Arabidopsis) UniProtKB:Q42545 Family Representative	GTPase activity GO:0003924	Review Missing No ai-review exists for this protein; its function and core-function coverage cannot yet be checked.
ftsz2	FTSZ2-1 (Arabidopsis) UniProtKB:O82533 Family Representative	GTPase activity GO:0003924	Review Missing No ai-review exists for this protein; its function and core-function coverage cannot yet be checked.
pdv_outer_bridge	PDV2 (Arabidopsis) UniProtKB:Q9XII1 Family Representative	phosphatidylinositol-4-phosphate binding GO:0070273	Review Missing No ai-review exists for this protein; its function and core-function coverage cannot yet be checked.
pdv_outer_bridge	PDV1 (Arabidopsis) UniProtKB:Q9FK13 Family Representative	phosphatidylinositol-4-phosphate binding GO:0070273	Review Missing No ai-review exists for this protein; its function and core-function coverage cannot yet be checked.
arc5_dynamin	ARC5 (Arabidopsis) UniProtKB:Q84N64 Family Representative	GTPase activity GO:0003924	Review Missing No ai-review exists for this protein; its function and core-function coverage cannot yet be checked.
mind_positioning	MinD subfamily PANTHER:PTHR43384:SF6 Family	ATP hydrolysis activity GO:0016887	Family Review Missing No supported structured family review is available for PANTHER:PTHR43384:SF6.
ftsz1	FtsZ1 subfamily PANTHER:PTHR30314:SF12 Family	GTPase activity GO:0003924	Family Review Missing No supported structured family review is available for PANTHER:PTHR30314:SF12.
ftsz2	FtsZ2 subfamily PANTHER:PTHR30314:SF16 Family	GTPase activity GO:0003924	Family Review Missing No supported structured family review is available for PANTHER:PTHR30314:SF16.
pdv_outer_bridge	PDV1 and PDV2 subfamilies PANTHER:PTHR33600:SF3 Family	phosphatidylinositol-4-phosphate binding GO:0070273	Family Review Missing No supported structured family review is available for PANTHER:PTHR33600:SF3.
pdv_outer_bridge	PDV1 and PDV2 subfamilies PANTHER:PTHR33600:SF4 Family	phosphatidylinositol-4-phosphate binding GO:0070273	Family Review Missing No supported structured family review is available for PANTHER:PTHR33600:SF4.
arc5_dynamin	ARC5 subfamily PANTHER:PTHR11566:SF78 Family	GTPase activity GO:0003924	Family Review Missing No supported structured family review is available for PANTHER:PTHR11566:SF78.

Gene-review completeness (0/7 grounded genes reviewed)

0 complete review(s) · 0 with deep research · 7 missing review · 0 reviewed but lacking deep research

Gene	Review	Complete	Deep research
FTSZ2-1 (Arabidopsis) O82533	✗	—	—
FTSZ1 (Arabidopsis) Q42545	✗	—	—
ARC5 (Arabidopsis) Q84N64	✗	—	—
ARC6 (Arabidopsis) Q9FIG9	✗	—	—
PDV1 (Arabidopsis) Q9FK13	✗	—	—
MIND1 (Arabidopsis) Q9MBA2	✗	—	—
PDV2 (Arabidopsis) Q9XII1	✗	—	—

Tree

Plastid division by the FtsZ and ARC5 ringsBiological Processplastid_division

Parts
1. 1. division-site positioning optional
2. MinD positioningMolecular Functionmin_positioning
  
  Annotons
  - MinD division-site positioning ATPase Family: MinD subfamily
3. 2. inner ring assembly
4. FtsZ1-FtsZ2 Z ringMolecular Functionz_ring
  
  Annotons
  - FtsZ1 stromal division ring GTPase Family: FtsZ1 subfamily
  - FtsZ2 stromal division ring GTPase Family: FtsZ2 subfamily
5. 3. ring linkage across the envelope
6. ARC6 inner-envelope bridgeMolecular Functionarc6_link
  
  Annotons
  - ARC6 inner-envelope ring bridge Family: ARC6 subfamily
7. 3. ring linkage across the envelope optional
8. PDV1/PDV2 outer-envelope bridgeMolecular Functionpdv_link
  
  Annotons
  - PDV1/PDV2 outer-envelope ring bridge Family: PDV1 and PDV2 subfamilies
9. 4. outer ring constriction
10. ARC5 outer ringMolecular Functionouter_ring
  
  Annotons
  - ARC5 dynamin-related division GTPase Family: ARC5 subfamily

Details

Context

ViridiplantaeNCBITaxon:33090

Plastid division by the FtsZ and ARC5 ringsBiological Processplastid_division

plastid fissionGO:0043572 chloroplast fissionGO:0010020

Context

ViridiplantaeNCBITaxon:33090

Connections

min_positioning -> z_ring Provides Input For

MinD restricts Z-ring assembly to the plastid midpoint.

z_ring -> arc6_link Provides Input For

ARC6 binds FtsZ2 and anchors the Z ring to the inner envelope.

arc6_link -> pdv_link Provides Input For

ARC6 binds PDV2 across the intermembrane space.

pdv_link -> outer_ring Provides Input For

PDV proteins recruit ARC5 to the division site.

z_ring -> outer_ring Provides Input For

The Z ring marks the division site where ARC5 assembles; in chlorophytes, which lack PDV, how ARC5 is recruited is not accounted for by this module.

Part 1: division-site positioning (optional)

MinD positioningMolecular Functionmin_positioning

Optional because MinD positions the division site rather than performing division.

Annotons

MinD division-site positioning ATPase

mind_positioning

Participant: Family: MinD subfamily

Family:

MinD subfamilyPANTHER:PTHR43384:SF6 Subfamily SF6 of PTHR43384, which does not separate plastid from bacterial MinD: besides Arabidopsis MIND1, the plastome MinD of five green algae (Chlorella, Oltmannsiellopsis, Tupiella, Mesostigma, Nephroselmis) and of two secondary-plastid lineages (Guillardia, Emiliania), it holds Escherichia coli (P0AEZ3), Bacillus subtilis (Q01464) and Synechocystis MinD and Rhodospirillum CooC (P31897). Any bacterial genome therefore satisfies this step; it must stay optional, or gain a tighter selector, before it could be required. Descent is shown by the protein's IBA rows in QuickGO, which cite the node; no Arabidopsis gene review exists for it in this repository.

Representative Members: MIND1 (Arabidopsis)UniProtKB:Q9MBA2

Function

ATP hydrolysis activityGO:0016887

Locations

plastid inner membraneGO:0009528

Stromal ATPase of the Min system that keeps the Z ring at the plastid midpoint.

GO_REF:0000033

PAINT IBD F:GO:0016887 at PTN000344128 in PTHR43384; no gene review for the Arabidopsis protein here.

file:interpro/panther/PTHR43384/PTHR43384-paint.tsv

PAINT ancestral-node rows for this step's family.

Part 2: inner ring assembly

FtsZ1-FtsZ2 Z ringMolecular Functionz_ring

Annotons

FtsZ1 stromal division ring GTPase

ftsz1

Participant: Family: FtsZ1 subfamily

Family:

FtsZ1 subfamilyPANTHER:PTHR30314:SF12 Subfamily SF12 of PTHR30314, whose only member listed locally is Arabidopsis FTSZ1. PTN000768282 (taxon:33090, Viridiplantae) places chloroplast fission. Other lineages' FtsZ1 proteins are not listed, so their genomes may fail this step for want of a selector. Descent is shown by the protein's IBA rows in QuickGO, which cite the node; no Arabidopsis gene review exists for it in this repository.

Representative Members: FTSZ1 (Arabidopsis)UniProtKB:Q42545

Function

GTPase activityGO:0003924 The F IBD at PTN000768275, the root FtsZ node shared with bacterial FtsZ.

Locations

plastid stromaGO:0009532

Tubulin-like GTPase that polymerises with FtsZ2 into the stromal Z ring at the plastid division site.

GO_REF:0000033

PAINT IBD F:GO:0003924 at PTN000768275 in PTHR30314; no gene review for the Arabidopsis protein here.

file:interpro/panther/PTHR30314/PTHR30314-paint.tsv

PAINT ancestral-node rows for this step's family.

FtsZ2 stromal division ring GTPase

ftsz2

Participant: Family: FtsZ2 subfamily

Family:

FtsZ2 subfamilyPANTHER:PTHR30314:SF16 Subfamily SF16 of PTHR30314 (Arabidopsis FTSZ2-1). FTSZ2-2 (Q9LXJ0) is placed in SF3 with bacterial FtsZ and Dictyostelium FszA, a mitochondrial division protein, so SF3 is not used and FTSZ2-2 is not a representative. Descent is shown by the protein's IBA rows in QuickGO, which cite the node; no Arabidopsis gene review exists for it in this repository.

Representative Members: FTSZ2-1 (Arabidopsis)UniProtKB:O82533

Function

GTPase activityGO:0003924 The F IBD at PTN000768275.

Locations

plastid stromaGO:0009532

Tubulin-like GTPase that forms the Z ring with FtsZ1 and links it to ARC6 in the inner envelope.

GO_REF:0000033

PAINT IBD F:GO:0003924 at PTN000768275 in PTHR30314; no gene review for the Arabidopsis protein here.

file:interpro/panther/PTHR30314/PTHR30314-paint.tsv

PAINT ancestral-node rows for this step's family.

Part 3: ring linkage across the envelope

ARC6 inner-envelope bridgeMolecular Functionarc6_link

Annotons

ARC6 inner-envelope ring bridge

arc6_bridge

Participant: Family: ARC6 subfamily

Family:

ARC6 subfamilyPANTHER:PTHR33925:SF1 Subfamily PTHR33925:SF1, which holds Arabidopsis ARC6 only; its paralogue CDP1/PARC6 (Q8VY16) is in SF2 and is not selected. Other green lineages may fail this step for want of a selector. PTN008660143 is a family-level node with no taxon whose P IBD is also seeded by AT3G19180 (CDP1); it carries C and P IBDs but no F IBD, so the step is left untyped. Descent is shown by the protein's IBA rows in QuickGO, which cite the node; no Arabidopsis gene review exists for it in this repository.

Representative Members: ARC6 (Arabidopsis)UniProtKB:Q9FIG9

Locations

plastid inner membraneGO:0009528

Inner-envelope protein that binds FtsZ2 in the stroma and PDV2 across the intermembrane space, linking the inner and outer division rings.

file:interpro/panther/PTHR33925/PTHR33925-paint.tsv

PAINT ancestral-node rows for this step's family.

Part 3: ring linkage across the envelope (optional)

PDV1/PDV2 outer-envelope bridgeMolecular Functionpdv_link

Optional because PAINT places the PDV node (PTN008658088) at Streptophyta (taxon:35493), so chlorophyte algae, which the module's Viridiplantae scope includes, are not expected to have PDV.

Annotons

PDV1/PDV2 outer-envelope ring bridge

pdv_outer_bridge

Participant: Family: PDV1 and PDV2 subfamilies

Family:

PDV1 and PDV2 subfamilies Subfamilies PTHR33600:SF3 (PDV2) and SF4 (PDV1), each listing only the Arabidopsis protein. Either satisfies the step. Descent is shown by the protein's IBA rows in QuickGO, which cite the node; no Arabidopsis gene review exists for it in this repository.

Representative Members: PDV2 (Arabidopsis)UniProtKB:Q9XII1 PDV1 (Arabidopsis)UniProtKB:Q9FK13

Function

phosphatidylinositol-4-phosphate bindingGO:0070273 The F IBD at PTN008658088, the node's only F term. It is a lipid-binding term, not a description of the ARC6 and ARC5 linkage that is this step's role.

Locations

plastid outer membraneGO:0009527

Outer-envelope proteins that bind ARC6 in the intermembrane space and recruit ARC5 to the division site.

GO_REF:0000033

PAINT IBD F:GO:0070273 at PTN008658088 in PTHR33600; no gene review for the Arabidopsis protein here.

file:interpro/panther/PTHR33600/PTHR33600-paint.tsv

PAINT ancestral-node rows for this step's family.

Part 4: outer ring constriction

ARC5 outer ringMolecular Functionouter_ring

Annotons

ARC5 dynamin-related division GTPase

arc5_dynamin

Participant: Family: ARC5 subfamily

Family:

ARC5 subfamilyPANTHER:PTHR11566:SF78 Subfamily SF78 of the dynamin family PTHR11566, which holds Arabidopsis ARC5 only. The location is the cytosolic face of the plastid outer membrane, where ARC5 assembles; neither cited node carries a plastid CC term. The family is not used, because it holds the dynamins of every organelle. ARC5 also descends from PTN000170389 (taxon:33090), which places peroxisome terms and records ARC5's role in peroxisome division; that node is not cited here. Descent is shown by the protein's IBA rows in QuickGO, which cite the node; no Arabidopsis gene review exists for it in this repository.

Representative Members: ARC5 (Arabidopsis)UniProtKB:Q84N64

Function

GTPase activityGO:0003924 The F IBD at PTN000170013, the dynamin family node.

Locations

plastid outer membraneGO:0009527

Cytosolic dynamin-related GTPase that is recruited to the outer surface of the division site and constricts the outer ring.

GO_REF:0000033

PAINT IBD F:GO:0003924 at PTN000170013 in PTHR11566; no gene review for the Arabidopsis protein here.

file:interpro/panther/PTHR11566/PTHR11566-paint.tsv

PAINT ancestral-node rows for this step's family.