Mon1-Ccz1 Rab7 exchange factor complex in Drosophila melanogaster

The Mon1-Ccz1 complex is the guanine nucleotide exchange factor for Rab7. Recruited to endosomes by Rab5 and phosphoinositides, it activates Rab7 and thereby drives Rab5-to-Rab7 conversion during endosome maturation, and it also acts on autophagosomes. Active Rab7 recruits the HOPS tethering complex for fusion with lysosomes. In metazoans the complex contains a third subunit, RMC1, whose Drosophila ortholog is Bulli; it is needed for full activity of the complex in vivo.

MODULE:dmel_mon1_ccz1_complexDRAFTCONCRETEProtein Complexmodules/dmel_mon1_ccz1_complex.yaml
Mon1-Ccz1 complexGO:0035658
FB:FBgg0000153
FlyBase gene group MCC: Mon1-ccz1 complex
FlyBase release FB2026_03 groups 3 D. melanogaster genes as mon1-ccz1 complex (MCC); this module models that group.
GO:0035658
Mon1-Ccz1 complex
GO term grounding the module as Mon1-Ccz1 complex.

Decomposition. Mon1 and Ccz1 form the catalytic heterodimer; Bulli (RMC1) is modelled as a separate accessory part because its precise contribution to activity and membrane targeting in vivo is less defined. FlyBase groups realized by this module: MCC (FBgg0000153). Participants were generated from the FlyBase gene-group membership and mapped to UniProtKB by projects/FLYBASE_GENE_GROUPS/generate_modules.py from module_specs/dmel_mon1_ccz1_complex.yaml. Member genes with a gene review in this repository: Bulli, Ccz1, Mon1.

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

Derived QC

Recommended-field compliance

100.0% recommended fields populated

All recommended fields populated.

Module deep research

✗ none found

No MODULE:dmel_mon1_ccz1_complex 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) · 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
mon1_ccz1_heterodimer_complex PROTEIN_COMPLEX
Gene 		guanyl-nucleotide exchange factor activity
GO:0005085 		Participant Unchecked
No direct UniProt participant to compare. Abstract selectors and complex-wide activities cannot be inferred from donor or subunit gene reviews.

Gene-review completeness (3/3 grounded genes reviewed)

2 complete review(s) · 3 with deep research · 0 missing review · 0 reviewed but lacking deep research

Gene Review Complete Deep research
Bulli Q9VRX1 ✓ ✓ ✓
Ccz1 Q9VZL5 ✓ ✓ ✓
Mon1 Q9VR38 ✓ 18/19 ✓

Details

Context
Drosophila melanogasterNCBITaxon:7227
Mon1-Ccz1 complexProtein Complexdmel_mon1_ccz1_complex

Rab7 guanine nucleotide exchange factor complex of Mon1, Ccz1 and Bulli that drives endosome and autophagosome maturation.

Mon1-Ccz1 complexGO:0035658
Context
Drosophila melanogasterNCBITaxon:7227
Part 1: Rab7 GEF catalytic heterodimer
Mon1-Ccz1 heterodimerProtein Complexmon1_ccz1_heterodimer

Annotons

Mon1-Ccz1 heterodimer
mon1_ccz1_heterodimer_complex
Participant: Protein Complex: Mon1-Ccz1 heterodimer
Protein Complex:
Mon1-Ccz1 heterodimer
Active units:
Mon1
Participant: Gene Product: Mon1
Gene Product:
Mon1UniProtKB:Q9VR38
Ccz1
Participant: Gene Product: Ccz1
Gene Product:
Ccz1UniProtKB:Q9VZL5

Function

guanyl-nucleotide exchange factor activityGO:0005085
Part 2: accessory subunit
Bulli (RMC1)Protein Complexbulli

Annotons

Bulli Bulli (RMC1)
bulli_bulli
Participant: Gene Product: Bulli
Gene Product:
BulliUniProtKB:Q9VRX1