CDK13 evidence and annotation review

2026-10-10. CDK13 (Q14004) is a nuclear cyclin-dependent protein kinase with a long arginine/serine-rich region. This review preserves all 43 normally seeded annotations, their original source/evidence/qualifier/with-from fields, and both product records. The decisions are 28 ACCEPT, 10 KEEP_AS_NON_CORE, four MODIFY and one UNDECIDED. No NEW annotation is proposed. References to row numbers below are zero-based positions in the preserved seed.

The standing ClinGen project instruction governs supported generic protein interactions: retain them as non-core unless a more informative molecular function is justified. The three retained generic interactions are p32/C1QBP and two source-specific CDC37 associations. The four cyclin K interactions are refined to cyclin binding, because the partner class and the target's role are independently established. No partner's kinase, chaperone or RNA-degrading activity is assigned to CDK13.

Catalysis, complexes and core functions

PMID:20952539(https://pubmed.ncbi.nlm.nih.gov/20952539/) includes human CDK13 purified from HeLa nuclear material and its GST-CTD kinase assay in Figure 4C. Selected indexed full Results, Figure 7 and purification Methods were inspected independently, even though the unchanged repository cache is abstract-only. The CDK12-focused title does not exclude the CDK13 experiment. The paper's restrained in-vivo conclusions are retained; CDK12-specific results do not establish CDK13 DNA-repair activity.

PMID:22012619(https://pubmed.ncbi.nlm.nih.gov/22012619/) separates human cyclin K/CDK12 and cyclin K/CDK13 complexes in reciprocal experiments. The genuine normal full-text refresh was read for the selected complex/kinase Results. The initial normal abstract output remains archived. Only the new full cache, absent from the fixed main baseline, is proposed for publication.

PMID:26748711(https://pubmed.ncbi.nlm.nih.gov/26748711/) provides the load-bearing CDK13/cyclin K structure, CTD phosphorylation and human knockdown/rescue evidence. The authentic publisher PDF was inspected for selected Results, Figures 1, 4, 5 and 7 and construct/rescue Methods. Recombinant human protein domains expressed in insect cells are distinguished from full-length complexes recovered from HCT116 cells. CDK13 phosphorylates CTD Ser2/Ser5; recognition of a pre-existing phospho-Ser7 substrate does not demonstrate Ser7 catalysis. Existing transcription/elongation annotations are retained on phosphoregulation and transcript-output evidence, without inventing a measured elongation velocity. GO:0008024 describes the transcriptional cyclin/CDK complex class; the core uses the specific cyclin K-CDK13 complex.

The second catalytic core is protein serine kinase activity on RNA-processing proteins. PMID:37079685(https://pubmed.ncbi.nlm.nih.gov/37079685/) was read in the genuine full XML-derived cache, especially Figure 4D–I and corresponding Results. Human melanoma CDK13 interacts with nuclear ZC3H14; CDK13/cyclin T1 directly phosphorylates ZC3H14 Ser475 in a wild-type versus S475A substrate assay. Phosphomimetic recruitment experiments connect this site to PAXT-associated RNA-surveillance machinery. CDK13 performs phosphotransfer, not RNA degradation. No new RNA-decay process is inferred merely from perturbation or rescue. Zebrafish and mouse experiments in the paper retain their separate species scope.

The human CDC2L5 abstract in PMID:16721827(https://pubmed.ncbi.nlm.nih.gov/16721827/) independently establishes nuclear/speckle localization and changes in splice-site selection. PMID:18480452(https://pubmed.ncbi.nlm.nih.gov/18480452/) explicitly connects CDK13 to ASF/SF2 phosphorylation and splicing; only its authentic abstract was recovered, so uninspected kinase controls are not claimed. The directly read ZC3H14 assay supplies an independent catalytic example rather than treating a splicing phenotype as proof of every substrate relationship. Neither a splicing influence nor localization assigns intrinsic RNA cleavage to CDK13.

Target-specific interaction and screening evidence

CDK13-source-evidence.json preserves finite target records, source URLs and raw-response hashes. The IntAct extraction retains exact accessions, method, target/partner taxonomy, host, features, source publication and negative-interaction flag. Repeated release entries do not count as independent replication.

Row 6, RNA binding, is retained at screen resolution. The original PMID:22681889(https://pubmed.ncbi.nlm.nih.gov/22681889/) journal full text was not directly recovered. The first author's authentic institutional thesis, The mRNA-bound Proteome of a human cell-line and in early Drosophila embryogenesis, explicitly identifies the published HEK293 project in its contributions statement. Table S1 (PDF page 145) contains the exact CDK13 class II hit: enrichment in two of three UV/oligo(dT) capture experiments. Table S3 (page 150) distinguishes positive construct expression, failed immunoprecipitation and a blank CLIP result. A failed IP does not establish a negative RNA-binding test. Sequence specificity and a narrower RNA-target function remain unresolved. The evidence file records these manually transcribed cells and the downloaded PDF hash; it is not a fabricated publication cache.

Row 18 is contextual proteomic detection. Authentic PMC XML for PMID:22664934(https://pubmed.ncbi.nlm.nih.gov/22664934/), Table II, contains the exact CDK13_HUMAN entry, verified against Q14004. The normal full-text markdown omitted this table. The study used group-pooled Schirmer tear samples from 25 breast-cancer patients and 25 controls. Detection supports a non-core extracellular location, not active secretion or physiological extracellular kinase activity. For rows 19/42, the genuine Reactome event and input/output sets explicitly contain CDK13 in the ficolin-rich granule lumen and extracellular context. These are curated event/proteomic locations, not independent catalytic experiments.

Inferences, process scope and unresolved evidence

The ortholog used in the relevant automated and ISS assertions is mouse Cdk13 Q69ZA1. Its experimental splicing, cyclin and nuclear-complex annotations cite PMID:17261272(https://pubmed.ncbi.nlm.nih.gov/17261272/). The authentic abstract and donor annotations were checked; the HEK293T assay host does not make a mouse construct human. Independent human CDK13 evidence supports the retained broad functions. PAINT assertions are inherited-node judgments; target Q14004 appearing among experimental descendants is legitimate provenance, not circular evidence. No uninspected ancestral-node placement or PANTHER identifier is invented.

Row 33 remains a non-core hematopoietic context. PMID:1731328(https://pubmed.ncbi.nlm.nih.gov/1731328/) cloned human CHED, but the abstract explicitly places the antisense megakaryocyte-development assay in murine bone-marrow cultures. The review preserves the original assertion and this organism boundary; it does not describe human marrow experiments.

Row 40 retains the cell-cycle regulation inference as non-core. The actual ontology path is GO:0004693 is_a GO:0097472 part_of GO:0051726, consistent with GO_REF:0000108. Independently, PMID:41680470(https://pubmed.ncbi.nlm.nih.gov/41680470/) Figure 2d assays CDK13-specific knockdown and overexpression in human 786-O cells. The independently viewed publisher histograms show increased G1/decreased G2 fractions after knockdown and the opposite direction under overexpression. These are endpoint phase distributions, not measured transition rates. The displayed S fraction decreases after knockdown, contrary to the Results sentence saying both G1 and S increased; that sentence is not adopted. Figure 4e/f measures EdU incorporation, not a phase-specific rescue. No dual-inhibitor selectivity, CDK12 activity or CDK13-derived circular-RNA function is transferred to this protein.

Row 26, regulation of signal transduction, remains UNDECIDED. The full PMID:26748711 analysis reports signaling-category enrichment among affected transcripts. The inspected assays do not resolve a particular signaling rate or extent regulated by CDK13 itself. This evidence-specific limit is not a claim that the source curator used the wrong gene. The demonstrated kinase and transcriptional functions remain retained.

Research and access provenance

Normal fetch completed before manual review. Falcon reached the bounded time limit; the explicit Perplexity-lite attempt returned insufficient quota. No provider report was produced or fabricated. This file is the manual research record. Exact-main publication and PANTHER cache bytes are retained, separately from fresh normal variants. The current source-evidence file records primary-table and machine-record extracts; the isolated research packet additionally preserves source downloads, access receipts, immutable normal seed and independent core, screen and cell-cycle peer reports.

A selected full-text read is reported as such and does not claim that every figure or supplement was inspected. Full-text availability flags reflect actual external access as well as the normal cache. Abstract-only sources retain that limitation. All short quotations are confined to the annotation YAML; this notes file adds no verbatim source excerpts. The per-source quotation audit includes repeated excerpts and is an authoring check, not a repository validation rule.

2026-10-10 PR #4492 follow-up

This entry supersedes the initial decision count and unresolved signaling assessment above: 28 ACCEPT, 10 KEEP_AS_NON_CORE, four MODIFY and one MARK_AS_OVER_ANNOTATED. All 43 source objects, both product records and both molecular cores remain unchanged.

The full selected PMID:26748711(https://pubmed.ncbi.nlm.nih.gov/26748711/) Results make the measurement boundary concrete. Human HCT116 knockdown, expression microarrays, selected qRT-PCR and RNAi-resistant rescue establish transcript-output effects. Figure 7C categorizes affected genes by GO enrichment; it does not test transmission of a signal or a defined signaling response. Row 26 therefore marks the specific signaling-process assertion as over-annotated. This does not dismiss CDK13's established transcriptional regulation or claim universal absence of a signaling role.

The three externally inspected but abstract-only cached references (PMIDs 20952539, 26748711 and 22547058) now omit the ambiguous availability boolean. Their reference assessments explicitly distinguish repository-cache depth from actual external access, and short external evidence anchors use supporting_text_fulltext. The earlier blanket statement about availability flags is superseded by this explicit distinction. The schema's field description is general, while the validator's warning discusses uncached text; neither justifies pretending that actually accessed primary sections were inaccessible. External URLs, sections, download/response hashes and access limits are included in the existing evidence artifact. The protected publication caches were not edited.

Row 40 remains non-core on the directly tested endpoint phase-distribution changes after CDK13 loss or gain in human 786-O cells. PMID:41680470(https://pubmed.ncbi.nlm.nih.gov/41680470/) contains an internal S-phase discrepancy between its Results sentence and the displayed representative Figure 2d histogram. It is now recorded in a findings[].finding_review and the evidence artifact, including the actual PDF page, hash and panel values. The annotation reason does not choose an S direction and does not infer transit rates or a phase-specific rescue. This is a bounded internal inconsistency, not rejection of the paper's entire cell-cycle result.

The suggested Table S1 sign correction was checked against the actual Baltz thesis page 145. The source really prints positive 4.52 alongside negative L1/L2 values. Light-labeled UV capture produces negative heavy-to-light log ratios; the heavy-labeled swap reverses the direction. The artifact now names the value as source-reported and explains the ratio convention. It preserves the published number instead of replacing it with an arithmetic average of signed raw ratios. The target-level RNA-binding assessment is unchanged; that screening reference is categorized as supporting rather than central literature.

The optional C1QBP isoform-field addition is not made: the source assertion is gene-level, and the independently known tested-product detail stays in the reason and notes. The two CDC37 source interactions remain non-core at their recorded association resolution; no new binary interface or folding activity is assigned. The already supported protein-serine-kinase core remains grounded in the full ZC3H14 experiment; additional substrate and complex annotations are not needed to address this follow-up. The biological description was tightened by removing a curation-style contrast with RNA degradation.

All newly authored quotations occur only once in the YAML, including the disputed finding's source sentence. The aggregate audit includes both supporting_text and supporting_text_fulltext; this notes entry and the evidence interpretation add no verbatim source prose.