GDP-mannose is the mannose donor for N-glycan precursor assembly, GPI anchors and protein O-mannosylation (through dolichol-phosphate-mannose), and the precursor of GDP-fucose. It is made in the cytosol from hexose 6-phosphates. Hexokinases phosphorylate glucose or mannose; glucose 6-phosphate is isomerized to fructose 6-phosphate by glucose-6-phosphate isomerase (Pgi), and mannose-6-phosphate isomerase (Mpi) interconverts fructose 6-phosphate and mannose 6-phosphate. Phosphomannomutase (Pmm2) converts mannose 6-phosphate to mannose 1-phosphate, and GDP-mannose pyrophosphorylase, formed by the catalytic subunit Gmppb and the regulatory subunit Gmppa, condenses mannose 1-phosphate with GTP to make GDP-mannose.
Boundary. The module covers the seven FlyBase members. Pgi and the hexokinases are shared with glycolysis and act in many pathways; they are included because FlyBase places them in this group. The Gmppa-Gmppb pyrophosphorylase is modelled as one complex. Use of GDP-mannose for GDP-fucose synthesis is modelled in the GDP-fucose biosynthesis module. FlyBase groups realized by this module: MANGPG (FBgg0002055). 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_mannose_biosynthesis.yaml. None of the member genes has a gene review in this repository yet.
All recommended fields populated.
✗ none found
No MODULE:dmel_gdp_mannose_biosynthesis deep-research report alongside the module YAML.
✓ every leaf node grounds to a representative protein.
✓ every declared conforms_to bundle matches its template motif.
✓ every PRECEDES step chains, or its break is acknowledged via chaining_status.
0 gene-function check(s) reflected in core functions · 0 conflict(s) · 6 evidence or coverage gap(s) (6 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 |
|---|---|---|---|
| hexose_phosphorylation_hex_a | Hex-A UniProtKB:Q9W330 Gene |
hexokinase activity GO:0004396 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| hexose_phosphorylation_hex_c | Hex-C UniProtKB:A1Z9Z2 Gene |
hexokinase activity GO:0004396 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| glucose_phosphate_isomerization_pgi | Pgi UniProtKB:P52029 Gene |
glucose-6-phosphate isomerase activity GO:0004347 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| mannose_phosphate_isomerization_mpi | Mpi UniProtKB:Q9VH77 Gene |
mannose-6-phosphate isomerase activity GO:0004476 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| phosphomannomutation_pmm2 | Pmm2 UniProtKB:Q9VTZ6 Gene |
phosphomannomutase activity GO:0004615 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| gdp_mannose_pyrophosphorylase_complex/gmppb | Gmppb UniProtKB:Q7JZB4 Complex Unit |
mannose-1-phosphate guanylyltransferase (GTP) activity GO:0004475 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
0 complete review(s) · 0 with deep research · 7 missing review · 0 reviewed but lacking deep research
| Gene | Review | Complete | Deep research |
|---|---|---|---|
| Hex-C A1Z9Z2 | ✗ | — | — |
| Pgi P52029 | ✗ | — | — |
| Gmppb Q7JZB4 | ✗ | — | — |
| Gmppa Q8SXU3 | ✗ | — | — |
| Mpi Q9VH77 | ✗ | — | — |
| Pmm2 Q9VTZ6 | ✗ | — | — |
| Hex-A Q9W330 | ✗ | — | — |
Hexose phosphorylation and isomerization (Hex-A, Hex-C, Pgi, Mpi), Pmm2 and the Gmppa-Gmppb pyrophosphorylase convert hexoses to GDP-mannose.
Gmppb is the catalytic subunit; Gmppa is a catalytically inactive regulatory subunit.