O-glycosylation attaches sugars to the hydroxyl groups of serine, threonine or hydroxylysine. Flies use several independent O-glycosylation pathways, each started by a dedicated transferase. Mucin-type O-GalNAc glycans are initiated by a family of polypeptide GalNAc transferases (Pgant) and extended by core 1 galactosyltransferase (C1GalTA) and glucuronyltransferase. EGF repeats of Notch and other receptors carry O-fucose added by Ofut1 and elongated by the GlcNAc transferase Fringe, and O-glucose added by Rumi and extended with xylose by Shams and Xxylt. Thrombospondin repeats are O-fucosylated by Ofut2. O-mannose glycans are added in the ER by the Rotated abdomen-Twisted (POMT1-POMT2) complex and, on cadherins, by the TMTC transferases. Nuclear and cytosolic proteins are modified by single O-GlcNAc residues by Super sex combs (OGT) and the modification is removed by O-GlcNAcase, while EGF repeats receive extracellular O-GlcNAc from Eogt. Collagen hydroxylysines are galactosylated after hydroxylation by Plod.
Boundary. FlyBase's protein O-glycosylation group also contains the chondroitin sulfate and heparan sulfate proteoglycan biosynthesis subgroups (GACSB, GAHSB), which are xylose-initiated O-glycans; they are modelled in the separate module dmel_glycosaminoglycan_biosynthesis and are excluded here. The POMT1-POMT2 complex group is realized as the POMT variant of the O-mannosylation part. The O-GalNAc, O-fucose, O-glucose and hydroxylysine branches are shown with their elongation steps in order; the different O-glycan classes are independent of one another. No molecular function is given to GlcAT-P in this branch (its glucuronyltransferase specificity on core 1 has been shown in vitro but the GO term for that acceptor is not established for this reaction) or to the TMTC transferases, whose O-mannosyltransferase activity in flies is inferred from their human orthologs. Plod is listed by FlyBase under O-galactosylation because lysine hydroxylation precedes galactose transfer; Plod itself is a hydroxylase. The intracellular O-GlcNAc cycle is a regulatory modification of nucleocytoplasmic proteins, distinct from the secretory-pathway glycans. FlyBase groups realized by this module: POMT1-2C (FBgg0001683), POGLY (FBgg0002102). Subgroups folded into it: POGLCN, POFUC, POMAN, POGLC, POGAL, POGALN. 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_protein_o_glycosylation.yaml. Member genes with a gene review in this repository: fng, Ofut1.
All recommended fields populated.
✗ none found
No MODULE:dmel_protein_o_glycosylation deep-research report alongside the module YAML.
✓ every leaf node grounds to a representative protein.
✓ every declared conforms_to bundle matches its template motif.
2 gene-function check(s) reflected in core functions · 0 conflict(s) · 20 evidence or coverage gap(s) (23 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 |
|---|---|---|---|
| galnac_initiation_pgant1 | Pgant1 UniProtKB:Q6WV20 Gene |
polypeptide N-acetylgalactosaminyltransferase activity GO:0004653 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| galnac_initiation_pgant2 | Pgant2 UniProtKB:Q6WV19 Gene |
polypeptide N-acetylgalactosaminyltransferase activity GO:0004653 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| galnac_initiation_pgant3 | Pgant3 UniProtKB:Q9Y117 Gene |
polypeptide N-acetylgalactosaminyltransferase activity GO:0004653 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| galnac_initiation_pgant35a | Pgant35A UniProtKB:Q8MVS5 Gene |
polypeptide N-acetylgalactosaminyltransferase activity GO:0004653 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| galnac_initiation_pgant4 | Pgant4 UniProtKB:Q8IA42 Gene |
polypeptide N-acetylgalactosaminyltransferase activity GO:0004653 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| galnac_initiation_pgant5 | Pgant5 UniProtKB:Q6WV17 Gene |
polypeptide N-acetylgalactosaminyltransferase activity GO:0004653 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| galnac_initiation_pgant6 | Pgant6 UniProtKB:Q6WV16 Gene |
polypeptide N-acetylgalactosaminyltransferase activity GO:0004653 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| galnac_initiation_pgant7 | Pgant7 UniProtKB:Q8MV48 Gene |
polypeptide N-acetylgalactosaminyltransferase activity GO:0004653 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| galnac_initiation_pgant8 | Pgant8 UniProtKB:Q9VUT6 Gene |
polypeptide N-acetylgalactosaminyltransferase activity GO:0004653 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| galnac_initiation_pgant9 | Pgant9 UniProtKB:Q8MRC9 Gene |
polypeptide N-acetylgalactosaminyltransferase activity GO:0004653 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| core1_galactosylation_c1galta | C1GalTA UniProtKB:Q7K237 Gene |
N-acetylgalactosaminide beta-1,3-galactosyltransferase activity GO:0016263 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| egf_o_fucosylation_ofut1 | Ofut1 UniProtKB:Q9V6X7 Gene |
peptide-O-fucosyltransferase activity GO:0046922 |
Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass). |
| fringe_elongation_fng | fng UniProtKB:Q24342 Gene |
O-fucosylpeptide 3-beta-N-acetylglucosaminyltransferase activity GO:0033829 |
Core Supported
The GO molecular function is reflected in core_functions (exact term or a reviewed subclass). |
| tsr_o_fucosylation_ofut2 | Ofut2 UniProtKB:Q9W589 Gene |
peptide-O-fucosyltransferase activity GO:0046922 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| egf_o_glucosylation_rumi | rumi UniProtKB:Q8T045 Gene |
EGF-domain serine glucosyltransferase activity GO:0140561 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| first_xylosylation_shams | shams UniProtKB:Q9VBY3 Gene |
UDP-D-xylose:beta-D-glucoside alpha-1,3-D-xylosyltransferase activity GO:0140563 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| second_xylosylation_xxylt | Xxylt UniProtKB:Q9W1D1 Gene |
xylosyl alpha-1,3-xylosyltransferase activity GO:0140560 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| pomt_complex_complex | PROTEIN_COMPLEX Gene |
dolichyl-phosphate-mannose-protein mannosyltransferase activity GO:0004169 |
Participant Unchecked
No direct UniProt participant to compare. Abstract selectors and complex-wide activities cannot be inferred from donor or subunit gene reviews. |
| intracellular_o_glcnac_transfer_sxc | sxc UniProtKB:Q0E9P3 Gene |
protein O-acetylglucosaminyltransferase activity GO:0097363 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| o_glcnac_removal_oga | Oga UniProtKB:Q9VDC9 Gene |
[protein]-3-O-(N-acetyl-D-glucosaminyl)-L-serine/L-threonine O-N-acetyl-alpha-D-glucosaminase activity GO:0102571 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| egf_o_glcnac_transfer_eogt | Eogt UniProtKB:Q9VQB7 Gene |
protein O-acetylglucosaminyltransferase activity GO:0097363 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| lysine_hydroxylation_plod | Plod UniProtKB:Q9VTH0 Gene |
procollagen-lysine 5-dioxygenase activity GO:0008475 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| hydroxylysine_galactosyl_transfer_cg31915 | CG31915 UniProtKB:Q8IPK4 Gene |
procollagen galactosyltransferase activity GO:0050211 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
2 complete review(s) · 2 with deep research · 27 missing review · 0 reviewed but lacking deep research
| Gene | Review | Complete | Deep research |
|---|---|---|---|
| fng Q24342 | ✓ | ✓ | ✓ |
| Ofut1 Q9V6X7 | ✓ | ✓ | ✓ |
| sxc Q0E9P3 | ✗ | — | — |
| Pgant6 Q6WV16 | ✗ | — | — |
| Pgant5 Q6WV17 | ✗ | — | — |
| Pgant2 Q6WV19 | ✗ | — | — |
| Pgant1 Q6WV20 | ✗ | — | — |
| C1GalTA Q7K237 | ✗ | — | — |
| Tmtc3 Q7K4B6 | ✗ | — | — |
| Pgant4 Q8IA42 | ✗ | — | — |
| CG31915 Q8IPK4 | ✗ | — | — |
| Pgant9 Q8MRC9 | ✗ | — | — |
| Pgant7 Q8MV48 | ✗ | — | — |
| Pgant35A Q8MVS5 | ✗ | — | — |
| rumi Q8T045 | ✗ | — | — |
| Tmtc2 Q9V3X5 | ✗ | — | — |
| shams Q9VBY3 | ✗ | — | — |
| Oga Q9VDC9 | ✗ | — | — |
| Tmtc4 Q9VF81 | ✗ | — | — |
| Eogt Q9VQB7 | ✗ | — | — |
| Tmtc1 Q9VQE9 | ✗ | — | — |
| GlcAT-P Q9VTG7 | ✗ | — | — |
| Plod Q9VTH0 | ✗ | — | — |
| rt Q9VTK2 | ✗ | — | — |
| Pgant8 Q9VUT6 | ✗ | — | — |
| Xxylt Q9W1D1 | ✗ | — | — |
| Ofut2 Q9W589 | ✗ | — | — |
| tw Q9W5D4 | ✗ | — | — |
| Pgant3 Q9Y117 | ✗ | — | — |
Independent pathways that initiate and extend O-GalNAc, O-fucose, O-glucose, O-mannose, O-GlcNAc and hydroxylysine-linked galactose glycans on proteins.