sec59 (Q9Y7T6) — evidence and prediction assessment

Sec59 is an endoplasmic-reticulum membrane dolichol kinase that produces dolichyl phosphate by CTP-dependent phosphorylation of dolichol. Dolichyl phosphate supplies the lipid carrier needed for protein N-glycosylation, O-mannosylation and GPI-anchor formation. Conserved Sec59/DOLK orthology supports this function in fission yeast; the related CTP-dependent phosphorylation of diacylglycerol is a distinct enzyme activity.

Evidence and family boundary

The full 504-aa target has a curated Sec59/DOLK assignment and multipass ER membrane architecture. Its P20048 ortholog source traces to experiments. PMID:1323123(https://pubmed.ncbi.nlm.nih.gov/1323123/) links the budding-yeast sec59 defect to loss of dolichol kinase and depletion of dolichyl phosphate; adding the lipid carrier restores downstream mannose-carrier synthesis. PMID:12213788(https://pubmed.ncbi.nlm.nih.gov/12213788/) distinguishes CTP-dependent dolichol phosphorylation from DAG kinase activity.

This supports target function by orthology, not a claim that those enzyme assays used pombe Sec59. The target HDA ER observation is retained despite Falcon’s failure to retrieve it. Dolichol-phosphate-mannose biosynthesis is valid downstream process participation through precursor supply; the direct core reaction is dolichol phosphorylation, not mannose transfer.

External ProtNLM statements

Exact retained output. These are name/location claims, not emitted GO/EC predictions. CNN denotes overlap with existing supported annotation; it does not establish literal membership in the training set.

Claim type Verbatim output Assessment Evidence and interpretation
name dolichol kinase CNN The target has the full membrane-kinase architecture and a curated transfer from experimentally characterized P20048/Sec59. Donor biochemistry distinguishes CTP-dependent dolichol phosphorylation from DAG kinase activity (PMID:1323123; PMID:12213788).
location Membrane LSP The target is more specifically an ER membrane protein according to the curated localization and membrane topology. The broad membrane statement is correct but adds no compartment resolution (PMID:16823372; Q9Y7T6).

Source quotations

PMID:12213788(https://pubmed.ncbi.nlm.nih.gov/12213788/):

Dolichol kinase (DK) catalyzes the CTP-mediated phosphorylation of dolichol in
eukaryotic cells, the terminal step in dolichyl monophosphate (Dol-P)
biosynthesis de novo.

Research provenance

The genuine Falcon report is retained with its provider metadata and artifact. Its conclusions were checked against the target record, exact accession and primary sources described above. Scientific uncertainties are recorded as UNC/UNDECIDED findings rather than a request for another reviewer to perform this assessment.

2026-10-21 — Full re-review, independent of the ProtNLM2 predictions

Identity: Q9Y7T6 is the reviewed, canonical, full-length (504 aa) UniProt entry for SPCC63.10c/sec59.
It is not an isoform, fragment or alternative gene model. Ten predicted TM helices (first at 56-76),
Polypren_kinase domain (IPR032974).

Evolutionary grounding:
- PANTHER: PTHR13205:SF15 (DOLICHOL KINASE), the same subfamily as S. cerevisiae SEC59 (P20048, 519 aa)
and human DOLK (Q9UPQ8, 538 aa) [file:interpro/panther/PTHR13205/PTHR13205-entries.csv "sec59,504,PTHR13205:SF15,DOLICHOL KINASE"].
- PAINT node PTN000324722 (taxon:2759) carries GO:0004168, GO:0005789 and GO:0043048 by IBD, seeded by
SGD:S000004615 (SEC59), Q9UPQ8 (DOLK), Q38DD5 and AT3G45040. Transfer of activity to pombe is therefore
phylogenetically grounded, not best-hit based.
- Donor biochemistry: PMID:1323123;
Dol-P drops to <10% at restrictive temperature and Dol-P-Man synthesis is rescued by exogenous Dol-P.
PMID:12213788 human DOLK complements sec59-1 and separates dolichol from DAG kinase activity.
- Pombe-specific evidence: only the proteome-wide YFP localization (PMID:16823372; ER), curated by UniProt
as ER membrane. No pombe enzymology.

Decisions (8 rows): GO:0004168 x3 (IBA, IEA, ISS) ACCEPT; GO:0005783 HDA MODIFY -> GO:0005789; GO:0005789 x2
ACCEPT; GO:0043048 IBA ACCEPT; GO:0180047 IC KEEP_AS_NON_CORE. On GO:0180047: the definition covers
"reactions and pathways resulting in the formation" of Dol-P-Man, and Sec59 makes the Dol-P that becomes
its lipid moiety, so it catalyzes a pathway step (not substrate-only); kept non-core because Dol-P also feeds
Dol-PP-oligosaccharide and Dol-P-Glc. No NEW terms: downstream N-glycosylation/O-mannosylation/GPI anchoring
are precursor supply and are not proposed.

Changes vs previous version: replaced templated reasons with row-specific reasoning grounded in PANTHER SF15 /
PTN000324722; HDA row now cites the UniProt subcellular-location line and the screen abstract rather than the
function line; added reference_review entries; added PANTHER entries inventory as a reference; added
suggested question/experiment.

Relative: S. cerevisiae SEC59 (P20048), same subfamily SF15 and PAINT donor; complete review exists at
genes/yeast/SEC59/SEC59-ai-review.yaml. Human DOLK review (genes/human/DOLK) is DRAFT.
PANTHER family review interpro/panther/PTHR13205/PTHR13205-review.yaml places sec59 in SF15; no disagreement.
Modules: modules/dolichol_phosphate_sugar_donor_supply.yaml (lists sec59 Q9Y7T6), modules/dolichyl_phosphate_biosynthesis.yaml.