Chitin, a beta-1,4-linked polymer of N-acetylglucosamine, is the fibrous scaffold of the insect cuticle, tracheal linings and the peritrophic matrix of the midgut. It is synthesized at the plasma membrane by chitin synthases: Krotzkopf verkehrt (kkv) makes chitin of the epidermal cuticle and trachea, and Chs2 is the second chitin synthase, expressed in the gut. During molting and tissue remodelling, chitin is broken down by family 18 chitinases (Cht genes), which cleave the polymer into oligosaccharides, and by beta-N-acetylhexosaminidases (Hexo1, Hexo2), which release N-acetylglucosamine from the non-reducing ends.
Boundary. The module joins the FlyBase chitin biosynthesis (CHIYBI) and chitin catabolism (CHITCA) groups. UDP-N-acetylglucosamine synthesis, chitin deacetylases and chitin-binding cuticle proteins are not parts. Chitinase activity is not assigned to individual Cht genes because activity has not been shown for most of them. The fused lobes hexosaminidase is not a FlyBase member of the group and is not included. FlyBase groups realized by this module: CHIYBI (FBgg0002045), CHITCA (FBgg0002046). 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_chitin_metabolism.yaml. None of the member genes has a gene review in this repository yet.
All recommended fields populated.
✗ none found
No MODULE:dmel_chitin_metabolism 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) · 4 evidence or coverage gap(s) (4 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 |
|---|---|---|---|
| chitin_synthesis_kkv | kkv UniProtKB:Q8IPN4 Gene |
chitin synthase activity GO:0004100 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| chitin_synthesis_chs2 | Chs2 UniProtKB:Q9VNW7 Gene |
chitin synthase activity GO:0004100 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| oligosaccharide_hydrolysis_hexo1 | Hexo1 UniProtKB:Q0E8H9 Gene |
beta-N-acetylhexosaminidase activity GO:0004563 |
Review Missing
No ai-review exists for this protein; its function and core-function coverage cannot yet be checked. |
| oligosaccharide_hydrolysis_hexo2 | Hexo2 UniProtKB:Q9W3C4 Gene |
beta-N-acetylhexosaminidase activity GO:0004563 |
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 · 14 missing review · 0 reviewed but lacking deep research
| Gene | Review | Complete | Deep research |
|---|---|---|---|
| Cht6 M9NDS9 | ✗ | — | — |
| Hexo1 Q0E8H9 | ✗ | — | — |
| kkv Q8IPN4 | ✗ | — | — |
| Cht12 Q8MLW8 | ✗ | — | — |
| Cht5 Q9VFR3 | ✗ | — | — |
| Chs2 Q9VNW7 | ✗ | — | — |
| Cht7 Q9VZV2 | ✗ | — | — |
| Cht2 Q9W092 | ✗ | — | — |
| Cht9 Q9W2M5 | ✗ | — | — |
| Cht4 Q9W2M6 | ✗ | — | — |
| Cht8 Q9W2M7 | ✗ | — | — |
| Hexo2 Q9W3C4 | ✗ | — | — |
| Cht11 Q9W3V1 | ✗ | — | — |
| Cht10 Q9W5U2 | ✗ | — | — |
Chitin synthesis by Kkv and Chs2, and chitin degradation by chitinases and beta-N-acetylhexosaminidases.
Family 18 chitinase genes grouped by FlyBase as chitin catabolism enzymes; individual activities and substrates have mostly not been measured.