CDKN2A

Summary: p16 can repress NF-kappaB-dependent transcription in the tested human cells.

Reason: The full primary Figures 1–4 and associated text show p16–RELA association, a purified-protein overlay and reduced NF-kappaB luciferase reporter activity in HeLa/293 cells, including TNF stimulation. This is transcriptional regulation through a transcription factor, not direct DNA binding or an intrinsic polymerase activity. Retain this context-dependent activity outside the principal CDK4/6 inhibitory core.

Summary: p16 inhibits integrin-dependent cell spreading in the reported matrix context.

Reason: The recovered full primary Results and Figure 10 test full-length p16 expression in human VUP15 melanoma cells: spreading and attachment on vitronectin are reduced at the 12-hour endpoint, and CDK6 co-expression reverses the effect. Separate acute CKI-peptide experiments in hamster CS-1 and human HUVEC cells inhibit spreading while retaining initial attachment. Retain the existing negative cell-matrix adhesion regulation as non-core with these assay distinctions; p16 is not itself an integrin receptor or PKC enzyme.

Summary: A CDKN2A entry is present in the RNA-capture dataset, but the exact protein-product assignment remains unresolved.

Reason: The authentic Baltz source reports CDKN2A as a class-III mRNA-capture candidate. The original table labels H1 as the label-swap experiment: L1/L2 crosslink the light channel, whereas H1 crosslinks the heavy channel. Normalizing raw H/L ratios to crosslinked/control therefore changes L1 -3.31 to +3.31 and retains H1 +1.39, giving the reported mean +2.35; L2 is missing. Thus two measured observations enrich, with only L1 exceeding the threefold cutoff. Class III is a screen-confidence category, not proof of a false interaction. The Methods identify IPI protein groups and then collapse isoforms; the inspected gene-level row does not provide CDKN2A-specific protein-group accessions or peptides that resolve P42771 from the unrelated ARF product. No independent target-specific RNA-binding assay was established in the inspected material. Absence of a canonical RNA-binding domain does not disprove this broad activity. Retain source-specific uncertainty about product attribution and reproducibility rather than converting a real capture signal into a confident negative.

Summary: The PAINT inhibitor assertion agrees with established p16 function.

Reason: This IBA represents inheritance of an ancestral INK4 inhibitor function. Its human p16 descendant evidence is legitimate support, not circularity; the additional INK4 descendants are not treated as pairwise transfers. Direct human p16 CDK4 inhibition and the p16–CDK6 structure support the target function, with no target-specific loss evidence. The exact ancestral placement was not reconstructed anew.

Summary: CDK4/6 inhibition is a defining p16 activity.

Reason: Retain the experimental source assertion and its original IDA provenance. The cached 1995 abstract emphasizes other INK4 members and does not expose every p16 control; this is not grounds for a wrong-paralog claim. Independent human p16 biochemical evidence in PMID:8259215 establishes the same inhibitor function.

Summary: Human p16 directly inhibits cyclin D–CDK4 kinase activity.

Reason: Full Results and Figures 1–3 identify a human p16 cDNA clone, native human p16/CDK4 association and inhibition of CDK4/cyclin D2-mediated GST-RB phosphorylation by purified His-tagged p16 from insect cells. The published clone is described as 148 residues; it is not relabeled as an assay of every current alternative product. The inhibitor activity belongs to p16, not as a kinase or a cyclin-binding protein.

Summary: The electronic inhibitor assignment is independently supported by p16 biochemistry.

Reason: Preserve the ARBA rule provenance. Its complete rule chain was not reconstructed; the same target-specific inhibitor activity is directly established by the human p16/CDK4 study and CDK6 complex structure.

Summary: The cited p16 study supports the established CDK-inhibitor role.

Reason: The full primary article expresses human p16 and compares CKI effects, including cell-cycle and proliferation assays. Its TAS statement is consistent with direct human p16 enzyme-inhibition evidence; expression-driven phenotypes alone are not presented as a new purified catalytic assay.

Summary: The full cited interaction experiments assay ARF, not the P42771 p16 product.

Reason: The recovered author manuscript Methods and Figure 2 specify full-length 132-residue human ARF and exon-1beta ARF fragments, with purified MBP–ARF/GST–spinophilin binding and ARF co-immunoprecipitation in COS-7 cells. p16 appears in background discussion, not those binding constructs. P42771-1 and Q8N726-1 are unrelated alternative-reading-frame proteins. Remove this source-specific p16 assignment while preserving the ARF source interpretation in the notes and separate Q8N726 review; do not manufacture an ARF source-isoform tag.

Summary: The protein-array record supports a p16–geminin association.

Reason: The exact human P42771/O75496 record linked to PMID:15232106 reports an in-vitro protein-array assay. It supports the low-resolution binding assertion, without establishing p16 as a replication-licensing inhibitor through geminin. The explicit ClinGen project instruction retains supported generic associations as non-core when a more informative molecular function is not established.

Summary: Refine the source-supported p16–CDK4 association to protein kinase binding.

Reason: The exact source supports p16 association with CDK4 by in-vitro protein array. This verified protein kinase partner supports GO:0019901 rather than generic protein binding. The binding assay alone is not treated as an inhibition assay; p16 inhibitor activity has separate primary evidence.

Proposed replacements: protein kinase binding

Summary: Refine the source-supported p16–CDK6 association to protein kinase binding.

Reason: The exact source supports p16 association with CDK6 by in-vitro protein array. This verified protein kinase partner supports GO:0019901 rather than generic protein binding. The binding assay alone is not treated as an inhibition assay; p16 inhibitor activity has separate primary evidence.

Proposed replacements: protein kinase binding

Summary: Refine the source-supported p16–CDK4 association to protein kinase binding.

Reason: The exact source supports p16 association with CDK4 by tagged co-immunoprecipitation in 293T cells, used as the positive control in full Figure 2e. This verified protein kinase partner supports GO:0019901 rather than generic protein binding. The binding assay alone is not treated as an inhibition assay; p16 inhibitor activity has separate primary evidence. The article foregrounds PFTK1, but the inspected full Results explicitly include the human p16/CDK4 positive control.

Proposed replacements: protein kinase binding

Summary: The source reports binding between p16 and ISOC2.

Reason: The primary abstract explicitly reports p16 bait, a human ISOC2 clone, pull-down/co-immunoprecipitation and tagged-protein colocalization. Retain the supported association with the full-text construct/control limits stated in the source assessment. The ISOC2 name is not used to infer a catalytic activity or a narrower enzyme-binding class. The explicit ClinGen project instruction retains supported generic associations as non-core when a more informative molecular function is not established.

Summary: Refine the source-supported p16–CDK4 association to protein kinase binding.

Reason: The exact source supports p16 association with CDK4 by co-immunoprecipitation in human fibroblasts and in-vitro interaction records. This verified protein kinase partner supports GO:0019901 rather than generic protein binding. The binding assay alone is not treated as an inhibition assay; p16 inhibitor activity has separate primary evidence. Wild-type controls are distinct from A20P/R24P variants: R24P impairs CDK4 binding while retaining CDK6 binding, so the mutant effect is not generalized to wild-type p16.

Proposed replacements: protein kinase binding

Summary: Refine the source-supported p16–CDK6 association to protein kinase binding.

Reason: The exact source supports p16 association with CDK6 by co-immunoprecipitation in human fibroblasts and in-vitro interaction records. This verified protein kinase partner supports GO:0019901 rather than generic protein binding. The binding assay alone is not treated as an inhibition assay; p16 inhibitor activity has separate primary evidence. Wild-type controls are distinct from A20P/R24P variants: R24P impairs CDK4 binding while retaining CDK6 binding, so the mutant effect is not generalized to wild-type p16.

Proposed replacements: protein kinase binding

Summary: Refine the source-supported p16–CDK4 association to protein kinase binding.

Reason: The exact source supports p16 association with CDK4 by in-vitro GST pull-down. This verified protein kinase partner supports GO:0019901 rather than generic protein binding. The binding assay alone is not treated as an inhibition assay; p16 inhibitor activity has separate primary evidence.

Proposed replacements: protein kinase binding

Summary: Source-linked assays support p16 association with PCNA.

Reason: Exact human pair records include pull-down, co-immunoprecipitation and colocalization in the cited study; the primary abstract also reports PCNA binding. Preserve the association without assigning PCNA or DNA-polymerase catalytic activity to p16. The explicit ClinGen project instruction retains supported generic associations as non-core when a more informative molecular function is not established.

Summary: Refine the source-supported p16–CDK6 association to protein kinase binding.

Reason: The exact source supports p16 association with CDK6 by in-vitro GST pull-down. This verified protein kinase partner supports GO:0019901 rather than generic protein binding. The binding assay alone is not treated as an inhibition assay; p16 inhibitor activity has separate primary evidence.

Proposed replacements: protein kinase binding

Summary: Source-linked assays support p16 association with MCM6.

Reason: The exact human P42771/Q14566 records include pull-down and co-immunoprecipitation, with in-vitro and NP-18 cell contexts retained in the accompanying extract. These associations do not establish p16 helicase activity or a particular effect on the MCM motor. The explicit ClinGen project instruction retains supported generic associations as non-core when a more informative molecular function is not established.

Summary: p16 associates with BRG1 in human cells.

Reason: The full primary Results and Figure 2 show endogenous p16/BRG1 co-immunoprecipitation in normal human fibroblasts, in addition to tagged-protein and two-hybrid assays. BRG1 depletion did not prevent the tested p16-induced arrest/senescence. Retain the association without inferring that p16 catalyzes or necessarily regulates chromatin remodeling; the isolated BRG1 fragment does not by itself resolve which enzymatic interface p16 recognizes. The explicit ClinGen project instruction retains supported generic associations as non-core when a more informative molecular function is not established.

Summary: The source-linked screen supports p16 association with DEAF1 (O75398).

Reason: The exact P42771-DEAF1 pair is positive in PMID:21988832: Table S2, Excel row 1745, records two library hits, LHU retransformation and positive tagged co-immunoprecipitation; IntAct EBI-3935272 and EBI-3944825 identify the same human pair. The Methods use GAL4 fusion constructs/library fragments and tagged proteins in HEK293T lysates, not endogenous native complexes. Canonical DEAF1 has nuclear/cytoplasmic localization compatible with p16, although this does not establish a physiological complex or resolve the assay isoform. Retain this source-scoped association under the project generic-binding instruction, without attributing DEAF1 transcriptional activity to p16.

Summary: The source-linked screen supports p16 association with HNRNPU (Q00839).

Reason: The exact P42771-HNRNPU pair is positive in PMID:21988832: Table S2, Excel row 367, records six library hits, LHU retransformation and positive tagged co-immunoprecipitation; IntAct EBI-3927672 and EBI-3944293 identify the same human pair. HNRNPU nuclear localization is compatible with the nuclear p16 pool, but the GAL4/library and tagged HEK293T lysate assays do not demonstrate an endogenous complex or direct RNA binding by p16. Retain the measured association as non-core under the project generic-binding instruction; do not transfer HNRNPU RNA/chromatin functions to its partner.

Summary: The source-linked screen supports p16 association with CRELD2 (Q6UXH1).

Reason: The P42771-CRELD2 association is a real positive engineered assay result: PMID:21988832 Table S2, Excel row 1749, records four library hits, LHU retransformation and positive tagged co-immunoprecipitation; IntAct EBI-3935312 and EBI-3944853 confirm the exact human pair. However, reviewed human CRELD2 has a signal peptide at residues 1-24 and a mature chain at 25-353 with ER localization, whereas p16 is nuclear/cytoplasmic. The Methods permit ORFs or fragments and use GAL4 fusions and tagged HEK293T lysate co-immunoprecipitation. The inspected source records do not resolve the CRELD2 fragment boundaries, routing of these constructs or colocalization of the tested pair. This leaves native physiological encounter and the biological interpretation of the binding annotation unresolved. It does not show the assay was wrong, prove a tag/lysis artifact, or establish that interaction is physically impossible in every context.

Summary: The source-linked screen supports p16 association with TDRD7 (Q8NHU6).

Reason: The exact P42771-TDRD7 pair is positive in PMID:21988832: Table S2, Excel row 1746, records one library hit, LHU retransformation and positive tagged co-immunoprecipitation; IntAct EBI-3935282 and EBI-3944839 identify the same human pair. Cytoplasmic TDRD7 localization is compatible with the cytoplasmic p16 pool. The GAL4/library and tagged HEK293T lysate assays establish a bounded association, without showing a native RNA-granule complex, purified binary affinity or a TDRD7-dependent p16 mechanism. Retain it as non-core under the project generic-binding instruction rather than transferring the partner RNA-related roles.

Summary: Refine the source-supported p16–CDK4 association to protein kinase binding.

Reason: The exact source supports p16 association with CDK4 by tandem-affinity purification in HEK293 cells. This verified protein kinase partner supports GO:0019901 rather than generic protein binding. The binding assay alone is not treated as an inhibition assay; p16 inhibitor activity has separate primary evidence.

Proposed replacements: protein kinase binding

Summary: Refine the source-supported p16–CDK4 association to protein kinase binding.

Reason: The exact source supports p16 association with CDK4 by tandem-affinity purification in HEK293 cells. This verified protein kinase partner supports GO:0019901 rather than generic protein binding. The binding assay alone is not treated as an inhibition assay; p16 inhibitor activity has separate primary evidence.

Proposed replacements: protein kinase binding

Summary: Refine the source-supported p16–CDK6 association to protein kinase binding.

Reason: The exact source supports p16 association with CDK6 by tandem-affinity purification in HEK293 cells. This verified protein kinase partner supports GO:0019901 rather than generic protein binding. The binding assay alone is not treated as an inhibition assay; p16 inhibitor activity has separate primary evidence.

Proposed replacements: protein kinase binding

Summary: Refine the source-supported p16–CDK4 association to protein kinase binding.

Reason: The exact source supports p16 association with CDK4 by U2OS co-immunoprecipitation and in-vitro pull-down. This verified protein kinase partner supports GO:0019901 rather than generic protein binding. The binding assay alone is not treated as an inhibition assay; p16 inhibitor activity has separate primary evidence. The source includes p16 substitutions at residues 53/87 and wild-type records; their differing affinities and import phenotypes are not collapsed into a claim that all variants behave identically.

Proposed replacements: protein kinase binding

Summary: Refine the source-supported p16–CDK6 association to protein kinase binding.

Reason: The exact source supports p16 association with CDK6 by U2OS co-immunoprecipitation and in-vitro pull-down. This verified protein kinase partner supports GO:0019901 rather than generic protein binding. The binding assay alone is not treated as an inhibition assay; p16 inhibitor activity has separate primary evidence. The source includes p16 substitutions at residues 53/87 and wild-type records; their differing affinities and import phenotypes are not collapsed into a claim that all variants behave identically.

Proposed replacements: protein kinase binding

Summary: Source-linked affinity capture-MS supports association of CDKN2A with CDK4.

Reason: BioGRID interaction 2941238 explicitly links human CDK4 bait and CDKN2A prey to PMID:24981860 by affinity capture-MS. The original paper abstract describes tagged human protein purifications, and this target record was inspected directly; the original mass-spectrometry table and peptide-level assignment were not inspected. Refine the supported association to protein kinase binding because the named partner is CDK4. Preserve the original P42771/P11802 source fields and recognize that this gene-level curated record does not independently resolve the CDKN2A product sequence. This AP-MS observation establishes association, not direct contact or kinase activation.

Proposed replacements: protein kinase binding

Summary: Refine the source-supported p16–CDK4 association to protein kinase binding.

Reason: The exact source supports p16 association with CDK4 by tagged affinity purification in HeLa cells. This verified protein kinase partner supports GO:0019901 rather than generic protein binding. The binding assay alone is not treated as an inhibition assay; p16 inhibitor activity has separate primary evidence.

Proposed replacements: protein kinase binding

Summary: The original human ORFeome screen reports a CDKN2A–GMNN yeast-two-hybrid interaction.

Reason: The genuine publisher supplementary workbook for PMID:27229929, Table S5A row 594, lists CDKN2A, GMNN and Y2H; source-linked BioGRID interaction 2380823 corroborates the same experiment. The primary Methods specify the human ORFeome v5.1 and reciprocal Y2H screening with reporter selection and autoactivation controls. Retain the supported generic association as non-core under the campaign instruction; the assay does not establish a physiological mechanism or transfer geminin activity to CDKN2A. The workbook and BioGRID identify the gene, while the existing GOA assertion supplies P42771 and O75496: the exact p16-versus-ARF ORF sequence was not independently recovered, so this retention explicitly defers to that curated product mapping rather than claiming sequence authentication.

Summary: Refine the source-supported p16–CDK4 association to protein kinase binding.

Reason: The exact source supports p16 association with CDK4 by tagged affinity purification in HEK293T cells. This verified protein kinase partner supports GO:0019901 rather than generic protein binding. The binding assay alone is not treated as an inhibition assay; p16 inhibitor activity has separate primary evidence.

Proposed replacements: protein kinase binding

Summary: Refine the source-supported p16–CDK6 association to protein kinase binding.

Reason: The exact source supports p16 association with CDK6 by tagged affinity purification in HEK293T cells. This verified protein kinase partner supports GO:0019901 rather than generic protein binding. The binding assay alone is not treated as an inhibition assay; p16 inhibitor activity has separate primary evidence.

Proposed replacements: protein kinase binding

Summary: Refine the source-supported p16–CDK4 association to protein kinase binding.

Reason: The exact source supports p16 association with CDK4 by tagged pull-down in HEK293 Flp-In T-REx cells. This verified protein kinase partner supports GO:0019901 rather than generic protein binding. The binding assay alone is not treated as an inhibition assay; p16 inhibitor activity has separate primary evidence.

Proposed replacements: protein kinase binding

Summary: Refine the source-supported p16–CDK6 association to protein kinase binding.

Reason: The exact source supports p16 association with CDK6 by tagged pull-down in HEK293 Flp-In T-REx cells. This verified protein kinase partner supports GO:0019901 rather than generic protein binding. The binding assay alone is not treated as an inhibition assay; p16 inhibitor activity has separate primary evidence.

Proposed replacements: protein kinase binding

Summary: Refine the source-supported p16–CDK4 association to protein kinase binding.

Reason: The exact source supports p16 association with CDK4 by tagged affinity purification in HEK293T cells. This verified protein kinase partner supports GO:0019901 rather than generic protein binding. The binding assay alone is not treated as an inhibition assay; p16 inhibitor activity has separate primary evidence.

Proposed replacements: protein kinase binding

Summary: Refine the source-supported p16–CDK6 association to protein kinase binding.

Reason: The exact source supports p16 association with CDK6 by tagged affinity purification in HEK293T cells. This verified protein kinase partner supports GO:0019901 rather than generic protein binding. The binding assay alone is not treated as an inhibition assay; p16 inhibitor activity has separate primary evidence. Multiple database records are not counted as independent biological replication.

Proposed replacements: protein kinase binding

Summary: Official OpenCell data identify CDK4 in the CDKN2A affinity-purification interaction dataset.

Reason: The original official OpenCell processed interaction CSV, line 4263, reports CDKN2A bait with CDK4; library metadata line 220 identifies the bait as P42771/p16-INK4a, transcript ENST00000304494, with an N-terminal endogenous fluorescent tag. The human HEK293T IP-MS context is described in the accessible original article text. Refine the supported association to protein kinase binding, preserving the original P11802 partner. The CDK4 mass-spectrometry protein group contains multiple accession strings, which are retained in the evidence artifact without asserting isoform-specific identification. This assay establishes association and does not on its own demonstrate purified direct binding, kinase activation or inhibition. Source numerical fields retain their original scale.

Proposed replacements: protein kinase binding

Summary: Official OpenCell data identify CDK6 in the CDKN2A affinity-purification interaction dataset.

Reason: The original official OpenCell processed interaction CSV, line 4264, reports CDKN2A bait with CDK6; library metadata line 220 identifies the bait as P42771/p16-INK4a, transcript ENST00000304494, with an N-terminal endogenous fluorescent tag. The human HEK293T IP-MS context is described in the accessible original article text. Refine the supported association to protein kinase binding, preserving the original Q00534 partner. This assay establishes association and does not on its own demonstrate purified direct binding, kinase activation or inhibition. Source numerical fields retain their original scale.

Proposed replacements: protein kinase binding

Summary: Refine the source-supported p16–CDK6 association to protein kinase binding.

Reason: The exact source supports p16 association with CDK6 by the human p16–CDK6 crystal structure, with p16 residues 1–156 and CDK6 residues 1–326. This verified protein kinase partner supports GO:0019901 rather than generic protein binding. The binding assay alone is not treated as an inhibition assay; p16 inhibitor activity has separate primary evidence.

Proposed replacements: protein kinase binding

Summary: The inferred nuclear activity is consistent with the p16 cell-cycle inhibitory core.

Reason: Retain the PAINT is_active_in qualifier and ancestry assertion. Human p16 has a nuclear pool and suppresses the nuclear RB-dependent cell-cycle program; the inference is consistent with its established inhibitor role. No target loss or divergence was identified, and the ancestral node was not reconstructed anew.

Summary: The cited human-cell study reports nuclear p16 localization.

Reason: The externally inspected full Results report p16–EGFP in both nuclei and cytoplasm in HUVECs, with the localization described as data not shown. This supports the original located_in assertion with its fusion-protein limit; it is not an endogenous-only microscopy claim.

Summary: The UniProt-derived nuclear location agrees with observed p16 localization.

Reason: Retain the electronic source mapping. Nuclear p16 is supported independently by the human-cell localization report and endogenous nuclear association studies; the SL mapping itself is not presented as a new experiment.

Summary: Nucleoplasmic localization is consistent with the nuclear regulatory pool.

Reason: Preserve the HPA immunofluorescence assertion and located_in qualifier. Nucleoplasm is compatible with the experimentally described nuclear p16 pool and its core cell-cycle regulatory role. This location does not imply DNA binding.

Summary: The PAINT cytoplasmic activity assertion is compatible with the p16 inhibitor role.

Reason: p16 has a genuine cytoplasmic pool and engages CDK4/6 before their productive cyclin-dependent activation. The original is_active_in assertion is retained as a phylogenetic judgment, supported by the curated cytosolic INK4–CDK reaction context, rather than derived solely from cytoplasmic staining. No target-specific loss was found; no new ancestral-node analysis is claimed. The inspected Reactome R-HSA-182594 machine record places both the input INK4/CDK entities and their output complex in GO:0005829 cytosol.

Summary: The cited study reports p16 in the cytoplasm as well as the nucleus.

Reason: The full HUVEC Results report p16–EGFP in both compartments, explicitly as data not shown. Preserve the located_in assertion and fusion-construct scope. The compartment is consistent with the cytoplasmic regulatory pool; localization alone is not used to prove an enzymatic reaction there.

Summary: The UniProt-derived cytoplasmic location is consistent with experimental p16 distribution.

Reason: Preserve this electronic location mapping, independently consistent with the HUVEC fusion localization and native p16 staining reported in the BRG1 study. No membrane residence or extracellular activity is inferred.

Summary: The source cytosolic p16 entity is compatible with the cytoplasmic regulatory pool.

Reason: The source reaction describes INK4 association with free CDK4/6 before cyclin-dependent activation. Retain only the existing located_in assertion. The event context does not transfer the catalytic or transcriptional activity of another participant to p16.

Summary: The source cytosolic p16 entity is compatible with the cytoplasmic regulatory pool.

Reason: The source event regulates translation of the p16 transcript; p16 is the protein product, not the miRNA effector. Retain only the existing located_in assertion. The event context does not transfer the catalytic or transcriptional activity of another participant to p16.

Summary: The source cytosolic p16 entity is compatible with the cytoplasmic regulatory pool.

Reason: The source event distinguishes p16 variants losing CDK4 binding from wild type and variants retaining CDK6 binding. Retain only the existing located_in assertion. The event context does not transfer the catalytic or transcriptional activity of another participant to p16.

Summary: The source cytosolic p16 entity is compatible with the cytoplasmic regulatory pool.

Reason: The source event distinguishes p16 mutants defective in CDK4/6 binding from the wild-type inhibitor. Retain only the existing located_in assertion. The event context does not transfer the catalytic or transcriptional activity of another participant to p16.

Summary: The source cytosolic p16 entity is compatible with the cytoplasmic regulatory pool.

Reason: The source event concerns MITF-dependent expression of p16; p16 is not thereby a MITF transcriptional cofactor. Retain only the existing located_in assertion. The event context does not transfer the catalytic or transcriptional activity of another participant to p16.

Summary: Ras-induced p16 accumulation does not by itself establish participation in the Ras relay cassette.

Reason: Full PMID:9054499 Results, Figures 2–6 and Methods establish induced p16 and a delayed antiproliferative response to oncogenic Ras. GO:0007265 describes signal relay through the Ras cassette. Cyclin D1/CDK4-R24C bypassed arrest in rat REF52 but not human IMR90; E1A has broader effects. These experiments do not establish selective human p16 relay activity. Mark the pathway specificity as over-annotated while retaining independent CKI and senescence functions.

Summary: The inherited antiproliferative role matches the p16 inhibitory core.

Reason: The PAINT ancestry assertion is supported by direct p16 inhibition of CDK4/6 and human-cell arrest experiments. The target appearing among descendants is legitimate experimental grounding, not circular evidence. No target-specific divergence was found.

Summary: Negative regulation of proliferation is an established p16 function.

Reason: The cached source abstract distinguishes telomere/ATM–p53–p21 arrest from a parallel p16 pathway in a subset of human cells. It does not contradict p16 antiproliferative activity. Retain the curator’s IDA assertion, independently supported by human p16 expression studies; the inaccessible full assay is not reconstructed from the title.

Summary: Human p16 overexpression suppresses cell-cycle progression in the cited endothelial model.

Reason: The inspected full Results and Figure 2 description show increased G1 and decreased S-phase representation after p16–EGFP expression in HUVECs. The p16-dependent senescence response requires an intact RB context. This supports the existing antiproliferative assertion without transferring the p21/p53 apoptotic effects to p16.

Summary: The source explicitly supports p16 cooperation in proliferative arrest.

Reason: The primary abstract states that HMGA proteins cooperate with p16 in heterochromatin formation and proliferative arrest. This agrees with direct independent p16 cell-cycle inhibition. Retain the existing IMP assertion while limiting source-specific mechanistic detail to the accessible abstract; it does not resolve the separate p16 focus-localization assertion.

Summary: p16 suppresses proliferation through an RB-dependent cell-cycle mechanism.

Reason: The primary abstract reports p16-induced G1 arrest in human cells with functional RB and contrasts RB-defective cells; separate mouse fibroblast experiments test the same dependency. This is a core p16 function, not evidence that p16 directly catalyzes RB modification.

Summary: CDK4 binding is an integral part of p16 inhibition.

Reason: The source directly reports human p16 binding to CDK4 and inhibition of the cyclin D/CDK4 enzyme. The existing kinase-binding MF is correct and supports the more mechanistic inhibitor core without requiring a second redundant core entry.

Summary: Human p16 expression inhibits cell population expansion and DNA synthesis in the cited adenoviral assays; the measured endpoint is proliferation rather than individual-cell biomass growth.

Reason: The full primary Results, Figure 2 and Methods of PMID:10208428 were inspected. The construct uses human p16 cDNA, including tests in human A549 cells; mouse MT1A2 experiments are separate. The growth assay counts viable cells daily, and the paper also measures thymidine incorporation, colony formation and DNA-content profiles. Early cytostasis precedes later cell death, so the later reduction in viable cell numbers is not interpreted wholly as proliferation inhibition. These assays support negative regulation of cell population proliferation, whereas GO:0030308 regulates cell growth as defined by GO:0016049, an increase in individual-cell size through accumulation of biosynthetic material. Refine this source-specific assertion to GO:0008285 while preserving the original term, IDA evidence and source fields. This does not claim that p16 can never affect cellular biomass.

Proposed replacements: negative regulation of cell population proliferation

Summary: The cited donor apoptosis experiment tests ARF loss rather than p16 loss.

Reason: The full PMID:20381282 Methods, Figures 4/5 and supplement distinguish p19ARF-deficient apoE-null mice from controls and retain measurable p16, including aortic p16 upregulation. The current mouse GO source puts the smooth-muscle apoptosis result on P51480, but P51480 is p16 whereas mouse ARF is Q64364. The supplied Ensembl protein also maps to p16; its separate historical GO record was not recovered. The experiment therefore does not support the p16 functional assignment. This is a product-level review distinction, not a claim that UniProt's external-product listing is erroneous. Preserve the source fields; the ARF biology is discussed in the separate Q8N726 review, without manufacturing new transferred annotations.

Summary: The cited donor apoptosis experiment tests ARF loss rather than p16 loss.

Reason: The full PMID:20381282 Methods, Figures 4/5 and supplement distinguish p19ARF-deficient apoE-null mice from controls and retain measurable p16, including aortic p16 upregulation. The current mouse GO source puts the smooth-muscle apoptosis result on P51480, but P51480 is p16 whereas mouse ARF is Q64364. The supplied Ensembl protein also maps to p16; its separate historical GO record was not recovered. The experiment therefore does not support the p16 functional assignment. This is a product-level review distinction, not a claim that UniProt's external-product listing is erroneous. Preserve the source fields; the ARF biology is discussed in the separate Q8N726 review, without manufacturing new transferred annotations.

Summary: The cited abstract supports p16 cooperation in senescence-associated heterochromatin formation but does not resolve p16 localization within those foci.

Reason: GO:0035985 is a cellular structure, and the original located_in qualifier asserts physical residence. PMID:16901784 is available only as an abstract in the normal cache and the accessible original publisher/repository records. Attempts to retrieve the full primary article, including targeted searches for its Results, Methods and figures, did not recover the target-level localization experiment. A role in forming a focus is not itself evidence of residence, but the abstract cannot establish that the curator lacked additional localization evidence. Preserve this experimental IDA assertion as unresolved; do not reject it as a wrong-gene or HMGA-only annotation on the basis of the title or abstract.

Summary: Negative regulation of CDK activity is the biological consequence of p16 inhibitor action.

Reason: Preserve the original acts_upstream_of_or_within qualifier. The 1995 source abstract foregrounds other INK4 proteins and its complete p16 control was not inspected; independent direct human p16/CDK4 inhibition establishes the same activity-regulation relationship. No wrong-paralog conclusion follows from the title.

Summary: The source supports p16 cooperation in repression of proliferation-associated transcription.

Reason: The accessible abstract attributes repression and stable arrest to cooperation between HMGA proteins and p16. Retain the experimental IMP assertion at this regulatory level while avoiding direct p16 DNA binding or an intrinsic chromatin-remodeling claim. The exact individual full-text transcription assay was not recovered; the conclusion is bounded to the positive abstract and established CKI–RB regulatory context.

Summary: p16 can bind the NF-kappaB RELA/p65 subunit.

Reason: Full Figures 1–3 show tagged and endogenous association in human cells and a renatured-protein overlay with recombinant p16 and p65, with p50 as a negative comparator. This supports the existing specific NF-kappaB-binding term in the tested TNF/INK4 context. It is retained outside the principal CDK-inhibition core; no universal constitutive association is claimed.

Summary: Cell-cycle regulation is central to p16 function.

Reason: The accessible abstract distinguishes a parallel p16 pathway from telomere-triggered ATM–p53–p21 signaling; the full target assay was not recovered, so its exact protocol is not reconstructed. Retain the existing broad process assertion, supported by independent p16 CDK inhibition and G1 arrest evidence. The core synthesis uses the informative G1/S process without adding a redundant NEW row.

Summary: Cell-cycle regulation is central to p16 function.

Reason: The primary report directly links human p16 binding to CDK4 with inhibition of the CDK4/cyclin D enzyme. Retain the existing broad process assertion, supported by independent p16 CDK inhibition and G1 arrest evidence. The core synthesis uses the informative G1/S process without adding a redundant NEW row.

Summary: Cell-cycle regulation is central to p16 function.

Reason: The externally inspected HUVEC Results and Figure 2 description show a p16–EGFP-dependent shift toward G1 and away from S phase. Retain the existing broad process assertion, supported by independent p16 CDK inhibition and G1 arrest evidence. The core synthesis uses the informative G1/S process without adding a redundant NEW row.

Summary: p16 promotes stable cell-cycle arrest in senescence contexts.

Reason: The electronic senescence assignment is independently supported by human p16 perturbation studies and the established CKI–RB mechanism. Preserve the ARBA provenance while acknowledging that its complete rule chain was not reconstructed. This does not imply that all senescence is p16-dependent.

Summary: Human p16 expression promotes senescence in the tested endothelial cells.

Reason: Full Results and Figures 4–7 describe increased senescence-associated beta-galactosidase after p16–EGFP expression and suppression of that response when RB is depleted. Retain a core senescence role through cell-cycle inhibition; the source’s separate p21/p53 apoptosis effects are not assigned to p16.

Summary: p16 contributes to replicative arrest in the tested human fibroblast context.

Reason: The primary abstract reports transient escape of HCA2 fibroblasts from replicative senescence after p16 siRNA, and the selected publisher Methods identify exon-1alpha-directed reagents that spare p14ARF. Keep this source-specific context as non-core: replicative senescence can also proceed through telomere/ATM–p53–p21 mechanisms and is not universally dependent on p16.

Summary: The PAINT G1/S-regulatory assertion agrees with p16 CDK inhibition.

Reason: Retain the phylogenetic inheritance assertion, with the target’s own descendant experimental evidence counted legitimately. Human p16 binds and inhibits CDK4/6 and restrains RB-dependent entry into S phase. No target-specific loss was found; no novel PAINT node placement is proposed.

Summary: Human p16 affects the G1/S cell-cycle transition.

Reason: The full cited study combines human p16 expression with DNA-content profiles, DNA-synthesis and cell-number measurements. Early cytostasis supports regulation of G1/S; later cell death is not misdescribed as exclusively a transition-rate measurement.

Summary: The electronic G1/S assertion is consistent with direct p16 evidence.

Reason: Preserve the ARBA source mapping. Independent biochemical and human-cell data support the p16–CDK4/6–RB regulatory mechanism; the entire automated rule was not reconstructed.

Summary: The cited donor apoptosis experiment tests ARF loss rather than p16 loss.

Reason: The full PMID:20381282 Methods, Figures 4/5 and supplement distinguish p19ARF-deficient apoE-null mice from controls and retain measurable p16, including aortic p16 upregulation. The current mouse GO source puts the macrophage apoptosis result on P51480, but P51480 is p16 whereas mouse ARF is Q64364. The supplied Ensembl protein also maps to p16; its separate historical GO record was not recovered. The experiment therefore does not support the p16 functional assignment. This is a product-level review distinction, not a claim that UniProt's external-product listing is erroneous. Preserve the source fields; the ARF biology is discussed in the separate Q8N726 review, without manufacturing new transferred annotations.

Summary: The cited donor apoptosis experiment tests ARF loss rather than p16 loss.

Reason: The full PMID:20381282 Methods, Figures 4/5 and supplement distinguish p19ARF-deficient apoE-null mice from controls and retain measurable p16, including aortic p16 upregulation. The current mouse GO source puts the macrophage apoptosis result on P51480, but P51480 is p16 whereas mouse ARF is Q64364. The supplied Ensembl protein also maps to p16; its separate historical GO record was not recovered. The experiment therefore does not support the p16 functional assignment. This is a product-level review distinction, not a claim that UniProt's external-product listing is erroneous. Preserve the source fields; the ARF biology is discussed in the separate Q8N726 review, without manufacturing new transferred annotations.