Dictyostelium counting-factor group-size control

The secreted-signal feedback system that sets the number of cells per aggregate (and hence fruiting-body size) in Dictyostelium discoideum. Aggregating cells secrete "counting factor" (CF), a large multisubunit complex whose principal component is Countin (CtnA); high CF activity decreases cell-cell adhesion and the size of cAMP-relay streams, breaking large aggregation territories into smaller groups. The cytosolic protein SmlA negatively regulates the secretion of counting factor: smlA-null cells oversecrete CF and form many small aggregates, whereas countin-null cells undersignal and form few large ones. The module is thus a two-element size rheostat — SmlA restrains CF output, CtnA is the secreted size-limiting signal. Phrased over the reviewed D. discoideum proteins. OUT OF SCOPE: the other CF subunits (CF45-1, CF50) which are not yet reviewed, and the downstream glucose/adhesion effectors of CF.

MODULE:dicty_counting_factor_size_controlDRAFTSignaling Pathwaymodules/dicty_counting_factor_size_control.yaml
regulation of aggregate size involved in sorocarp developmentGO:0031157
GO:0031157
regulation of aggregate size involved in sorocarp development
The module is grounded in regulation of aggregate size involved in sorocarp development (GO:0031157); both SmlA and CtnA carry this annotation.
file:DICDI/smlA/smlA-ai-review.yaml
smlA gene review (Dictyostelium discoideum)
Negative regulator grounding (UniProtKB:P54661); cytosolic SmlA restrains counting-factor secretion (its own molecular activity is undetermined).
file:DICDI/ctnA/ctnA-ai-review.yaml
ctnA gene review (Dictyostelium discoideum)
Counting-factor signal grounding (UniProtKB:Q86IV5, GO:0005102 signaling receptor binding); Countin is the principal secreted CF component.

Dictyostelium-specific group-size control module grounded to SmlA (P54661, no determined molecular function) and Countin/CtnA (Q86IV5, GO:0005102). SmlA acts intracellularly and is not itself secreted; it negatively regulates CF secretion (GO:0050709 in the smlA review). The other counting-factor subunits (CF45-1, CF50) are named but not grounded because they have not been reviewed. Named to signal Dictyostelium scope.

3Nodes
2Parts
0Variant Sets
0Variants
2Annotons
1Connections

Derived QC

Recommended-field compliance

100.0% recommended fields populated

All recommended fields populated.

Module deep research

✗ none found

No MODULE:dicty_counting_factor_size_control 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

1 gene-function check(s) reflected in core functions · 0 conflict(s) · 0 evidence or coverage gap(s) (1 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.

AnnotonParticipantFunctionAssessment
ctna_activity Countin (CtnA)
UniProtKB:Q86IV5
Gene 		signaling receptor binding
GO:0005102 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).

Feedback loops (advisory, prose-driven: a regulator counts as "feedback" when its own description says so)

✓ every negative regulator described as feedback has an upstream edge closing the loop.

  • smla_repression ⊣ countin_signal [input]
    smla_repression is a negative regulator with no upstream edge (not described as feedback)

Gene-review completeness (2/2 grounded genes reviewed)

1 complete review(s) · 0 with deep research · 0 missing review · 2 reviewed but lacking deep research

Gene Review Complete Deep research
ctnA Q86IV5 ✓ 17/18 ✗
smlA P54661 ✓ ✓ ✗

Details

Context
Dictyostelium discoideumNCBITaxon:44689
Counting factor size control (SmlA -| counting-factor / CtnA)Signaling Pathwaydicty_counting_factor_size_control
regulation of aggregate size involved in sorocarp developmentGO:0031157
Context
Dictyostelium discoideumNCBITaxon:44689

Connections

smla_repression -> countin_signal Negatively Regulates
SmlA restrains secretion of counting factor (Countin/CtnA); loss of SmlA oversecretes CF, increasing the size-limiting signal and yielding many small fruiting bodies.
Part 1: negative regulation of counting-factor secretion
cytosolic SmlA restrains secretion of counting factorRegulatory Stepsmla_repression

Annotons

SmlA: cytosolic repressor of counting-factor secretion
smla_regulator
Participant: Family: Small-aggregate protein family (SmlA)
Family:
Small-aggregate protein family (SmlA)PANTHER:PTHR35884
Representative Members: SmlA (Dictyostelium discoideum)UniProtKB:P54661

Locations

cytosolGO:0005829

Cytosolic protein with no recognizable catalytic/binding domain that negatively regulates secretion of counting factor; loss causes CF oversecretion and many small aggregates. Its molecular activity is undetermined, so no molecular-function term is asserted.

Part 2: secreted size-limiting counting-factor signal
Countin (CtnA), principal secreted counting-factor componentRegulatory Stepcountin_signal

Annotons

CtnA: Countin, secreted counting-factor ligand
ctna_activity
Participant: Gene: Countin (CtnA)
Gene:
Countin (CtnA)UniProtKB:Q86IV5

Function

signaling receptor bindingGO:0005102

Locations

extracellular regionGO:0005576

Principal secreted component of counting factor; high CtnA activity lowers cell-cell adhesion and stream size, breaking large aggregation territories into smaller groups.