De novo GDP-fucose biosynthesis in Drosophila melanogaster

GDP-L-fucose is the donor substrate for fucosyltransferases, including the O-fucosyltransferase that modifies Notch EGF repeats and the Golgi fucosyltransferases that fucosylate N-glycans. Drosophila makes it de novo from GDP-mannose in the cytosol: GDP-mannose 4,6-dehydratase (Gmd) forms GDP-4-keto-6-deoxymannose, and GDP-L-fucose synthase (Gmer) epimerizes and reduces this intermediate to GDP-L-fucose. GDP-fucose is then carried into the secretory pathway by two transporters, the Golgi GDP-fucose transporter (Gfr) and the endoplasmic reticulum transporter Efr. Loss of Gmd or of both transporters impairs Notch O-fucosylation and Notch signaling.

MODULE:dmel_gdp_fucose_biosynthesisDRAFTCONCRETEMetabolic Pathwaymodules/dmel_gdp_fucose_biosynthesis.yaml
'de novo' GDP-L-fucose biosynthetic processGO:0042351
FB:FBgg0002026
FlyBase gene group GDPFUC: De novo gdp-fucose biosynthesis
FlyBase release FB2026_03 groups 4 D. melanogaster genes as de novo gdp-fucose biosynthesis (GDPFUC); this module models that group.
GO:0042351
'de novo' GDP-L-fucose biosynthetic process
GO term grounding the module as 'de novo' GDP-L-fucose biosynthetic process.

Boundary. The module covers the four FlyBase members. GDP-mannose supply is modelled in the GDP-mannose biosynthesis module; the fucosyltransferases that consume GDP-fucose (for example O-fut1 and FucT6) are downstream and not parts. Drosophila is reported to lack the fucose salvage pathway, so the de novo route is its source of GDP-fucose. FlyBase groups realized by this module: GDPFUC (FBgg0002026). 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_gdp_fucose_biosynthesis.yaml. Member genes with a gene review in this repository: Efr, Gfr, Gmd, Gmer.

4Nodes
3Parts
0Variant Sets
0Variants
4Annotons
2Connections

Derived QC

Recommended-field compliance

100.0% recommended fields populated

All recommended fields populated.

Module deep research

✗ none found

No MODULE:dmel_gdp_fucose_biosynthesis 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.

Reaction chaining (advisory)

✓ every PRECEDES step chains, or its break is acknowledged via chaining_status.

  • gdp_mannose_dehydration → gdp_fucose_synthesis [NOT_CHECKED]
  • gdp_fucose_synthesis → gdp_fucose_transport [NOT_CHECKED]

Function consistency and core coverage

3 gene-function check(s) reflected in core functions · 0 conflict(s) · 0 evidence or coverage gap(s) (3 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
gdp_mannose_dehydration_gmd Gmd
UniProtKB:Q9VMW9
Gene 		GDP-mannose 4,6-dehydratase activity
GO:0008446 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
gdp_fucose_synthesis_gmer Gmer
UniProtKB:Q9W1X8
Gene 		GDP-L-fucose synthase activity
GO:0050577 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).
gdp_fucose_transport_gfr Gfr
UniProtKB:Q9VHT4
Gene 		GDP-fucose transmembrane transporter activity
GO:0005457 		Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass).

Gene-review completeness (4/4 grounded genes reviewed)

4 complete review(s) · 4 with deep research · 0 missing review · 0 reviewed but lacking deep research

Gene Review Complete Deep research
Efr Q9W429 ✓ ✓ ✓
Gfr Q9VHT4 ✓ ✓ ✓
Gmd Q9VMW9 ✓ ✓ ✓
Gmer Q9W1X8 ✓ ✓ ✓

Details

Context
Drosophila melanogasterNCBITaxon:7227
De novo GDP-fucose biosynthesisMetabolic Pathwaydmel_gdp_fucose_biosynthesis

Gmd and Gmer convert GDP-mannose to GDP-fucose, which Gfr and Efr import into the Golgi and endoplasmic reticulum.

'de novo' GDP-L-fucose biosynthetic processGO:0042351
Context
Drosophila melanogasterNCBITaxon:7227

Connections

The Gmd product is converted to GDP-L-fucose by Gmer.
Cytosolic GDP-L-fucose is imported into the secretory pathway.
Part 1: GDP-mannose to GDP-4-keto-6-deoxymannose
GDP-mannose dehydrationMetabolic Pathwaygdp_mannose_dehydration

Annotons

Gmd GDP-mannose dehydration
gdp_mannose_dehydration_gmd
Participant: Gene Product: Gmd
Gene Product:
GmdUniProtKB:Q9VMW9

Function

GDP-mannose 4,6-dehydratase activityGO:0008446
Part 2: GDP-4-keto-6-deoxymannose to GDP-L-fucose
GDP-L-fucose synthesisMetabolic Pathwaygdp_fucose_synthesis

Annotons

Gmer GDP-L-fucose synthesis
gdp_fucose_synthesis_gmer
Participant: Gene Product: Gmer
Gene Product:
GmerUniProtKB:Q9W1X8

Function

GDP-L-fucose synthase activityGO:0050577
Part 3: GDP-fucose transport into Golgi and endoplasmic reticulum
GDP-fucose import into the secretory pathwayMetabolic Pathwaygdp_fucose_transport

Gfr imports GDP-fucose into the Golgi; Efr acts in the endoplasmic reticulum and also transports other nucleotide sugars.

Annotons

Gfr GDP-fucose import into the secretory pathway
gdp_fucose_transport_gfr
Participant: Gene Product: Gfr
Gene Product:
GfrUniProtKB:Q9VHT4

Function

GDP-fucose transmembrane transporter activityGO:0005457

Golgi GDP-fucose transporter

Efr GDP-fucose import into the secretory pathway
gdp_fucose_transport_efr
Participant: Gene Product: Efr
Gene Product:
EfrUniProtKB:Q9W429

endoplasmic reticulum nucleotide-sugar transporter