CCN6

Summary: Retain the inherited integrin-binding activity as non-core, with its biochemical interface unresolved.

Reason: The PAINT assertion at PTN000142750 is a considered phylogenetic inference and does not require a separately published purified human-target assay to remain valid. Reviewed CCN6 contains TSP1 and CTCK domains, including CTCK residues 268–342; this is compatible with the family binding architecture and supplies no evidence of target loss. Family experimental studies distinguish several integrin-recognition sites across different domains, so the CTCK feature alone does not prove a particular CCN6 interface. Retain the curator-supported activity as non-core. The original IBD/tree/alignment and exact target interface remain unverified; this is an access qualification, not the reason to reject the inherited activity.

Summary: Human CCN6 acts extracellularly as a secreted ligand-binding regulator.

Reason: The inherited broad extracellular location is supported independently by secretion of human WISP3 into conditioned medium and extracellular ligand-response experiments. The target in the PAINT descendant list is expected evidence, not circularity; the node/MSA were not independently inspected.

Summary: Human CCN6 acts extracellularly as a secreted ligand-binding regulator.

Reason: The original cache is abstract-only and foregrounds mitochondrial experiments. The separately read 2016 body describes prior extracellular biology but is not treated as a new secretion assay. Human WISP3 conditioned-medium experiments in PMID:17823661 and the extracellular recombinant-protein assays in PMID:23424195 independently support this broad location, so retain the curator assertion.

Summary: Human CCN6 acts extracellularly as a secreted ligand-binding regulator.

Reason: The combined InterPro/UniProt location mapping agrees with the signal peptide and independently observed human WISP3 in conditioned medium. This supports extracellular region, without converting predicted secretion into precise solid-phase interstitial-matrix localization.

Summary: Human CCN6 acts extracellularly as a secreted ligand-binding regulator.

Reason: PMID:9843955 establishes the WISP family and human WISP3 expression but its abstract does not independently resolve the secretion assay. The broad location is nevertheless established by the later human conditioned-medium experiments, supporting retention with separate-source attribution.

Summary: Mitochondrial localization is supported, while its exact molecular activity there remains unresolved.

Reason: The current Human Protein Atlas CCN6 record reports supported mitochondrial staining with antibody HPA064196 in RT4, SK-MEL-30 and U2OS cells. This corroborates the independently read human chondrocyte experiments. Retain this compartment as non-core rather than attaching mitochondrial localization to the extracellular growth-factor-binding activity. Individual image pixels and the historical HPA submission were not reanalyzed. ORGANELLES batch 2 check (2026-10-24): HPA immunofluorescence resolves only the organelle, so the root term is what the assay can show; no sub-compartment is proposed (see the IEA row).

Summary: An intracellular CCN6 pool localizes to mitochondria in human cell experiments.

Reason: PMID:27252383 reports endogenous and expressed CCN6 mitochondrial colocalization and fractionation. The externally accessed original Methods distinguish human C-28/I2 chondrocytes from CCN6-Myc-transfected HEK293 membrane-extraction experiments; fractionation and protease-protection controls support association without proving a fixed membrane topology or a respiratory-complex subunit. Retain the experimentally observed location as non-core. ORGANELLES batch 2 check (2026-10-24): the cached copy is abstract-only, so the sub-mitochondrial data (mitoplast protease protection, carbonate extraction in transfected HEK293) cannot be quoted here; as read earlier they show association without fixing a side, so no sub-compartment row is added and the root row stands.

Summary: The electronic mitochondrial location is consistent with direct human evidence.

Reason: The UniProt subcellular-location mapping reflects experimentally reported mitochondrial association. It is retained as non-core because the intracellular regulatory mechanism has not been assigned a distinct molecular activity, not because extracellular secretion excludes an intracellular pool. Examined as a synthesis row (ORGANELLES batch 2, 2026-10-24): SL-0173 maps the curated line "Mitochondrion {ECO:0000269|PubMed:27252383}", the same paper as the direct row, so it adds no independent line; the organelle claim is nonetheless supported by two independent direct sources (PMID:27252383 and HPA antibody HPA064196). Rule 4 is not met: the only sub-compartment hint is UniProt's note of membrane association, while the N-terminal feature is an ER signal peptide (residues 1-23), not a mitochondrial presequence, so the import route and the side of the membrane are unknown. Stays at the root.

Summary: Retain inherited cell-adhesion involvement as a context-dependent non-core role.

Reason: The curated PTN000142750 inheritance is additionally compatible with an actual target adhesion endpoint. In the separately read primary PMID:25400723 Methods and Results, WISP3 knockdown reduces human gastric-cell adhesion to collagen I and IV while sparing fibronectin adhesion; the one-hour coated-plate assay is distinct from migration and proliferation readouts. This supports retaining the broad existing role as non-core, without claiming that knockdown establishes direct collagen or integrin binding or identifying the physical adhesion step. Original PAINT placement remains uninspected, and the target perturbation study corroborates a cellular role rather than replacing the phylogenetic inference.

Summary: Refine broad signaling to experimentally supported inhibition of IGF receptor signaling.

Reason: The inherited broad signaling assertion is biologically compatible with the target, but a demonstrated target process is more informative. PMID:23424195 establishes human WISP3–IGF1 binding and altered IGF1 availability and responses. In the separately read primary PMID:15140407 Methods, Results and captions, WISP3-containing conditioned medium lowers IGF-I-stimulated IGF1R, IRS1 and ERK phosphorylation in human SUM149 cells against empty-vector conditioned-medium controls. This supports the specific negative-regulation process. The conditioned-medium study explicitly leaves direct action versus another induced molecule unresolved; the separate binding assay establishes CCN6 own molecular work but does not prove that sequestration alone explains every cellular response. No intrinsic kinase activity, universal tumor-suppressor effect or new process row is asserted.

Proposed replacements: negative regulation of insulin-like growth factor receptor signaling pathway

Summary: Refine broad signaling to experimentally supported inhibition of IGF receptor signaling.

Reason: The electronic family-level signaling term can be refined using independent target experiments; domain membership alone does not establish the replacement. PMID:23424195 establishes human WISP3–IGF1 binding and altered IGF1 availability and responses. In the separately read primary PMID:15140407 Methods, Results and captions, WISP3-containing conditioned medium lowers IGF-I-stimulated IGF1R, IRS1 and ERK phosphorylation in human SUM149 cells against empty-vector conditioned-medium controls. This supports the specific negative-regulation process. The conditioned-medium study explicitly leaves direct action versus another induced molecule unresolved; the separate binding assay establishes CCN6 own molecular work but does not prove that sequestration alone explains every cellular response. No intrinsic kinase activity, universal tumor-suppressor effect or new process row is asserted.

Proposed replacements: negative regulation of insulin-like growth factor receptor signaling pathway

Summary: Refine broad signaling to experimentally supported inhibition of IGF receptor signaling.

Reason: The original PMID:9843955 abstract separates WISP1/2 induction by Wnt1 from identification and expression of WISP3; the replacement is supported by later target experiments, not assigned retrospectively to that original paper. PMID:23424195 establishes human WISP3–IGF1 binding and altered IGF1 availability and responses. In the separately read primary PMID:15140407 Methods, Results and captions, WISP3-containing conditioned medium lowers IGF-I-stimulated IGF1R, IRS1 and ERK phosphorylation in human SUM149 cells against empty-vector conditioned-medium controls. This supports the specific negative-regulation process. The conditioned-medium study explicitly leaves direct action versus another induced molecule unresolved; the separate binding assay establishes CCN6 own molecular work but does not prove that sequestration alone explains every cellular response. No intrinsic kinase activity, universal tumor-suppressor effect or new process row is asserted.

Proposed replacements: negative regulation of insulin-like growth factor receptor signaling pathway

Summary: Secreted human CCN6 can modify growth-factor communication between cells.

Reason: The original TAS is broader than the WISP-family discovery experiments visible in the 1998 abstract. Independently, human WISP3-containing conditioned medium alters ligand-driven responses in recipient cells and recombinant WISP3 modifies IGF1 responses in human chondrocytes. This supplies direct work in extracellular communication without assigning every CCN-family pathway to CCN6.

Summary: Retain the curated inherited heparin-binding activity as non-core without claiming direct target verification.

Reason: PTN000142748 represents a curator-placed ancestral assertion, not a one-donor similarity transfer. The preserved CCN6 TSP1/CTCK architecture is compatible with CCN-family glycosaminoglycan-binding mechanisms, and no target-specific loss or demonstrated placement error was identified. Retain that positive inherited evidence as non-core. Domain conservation alone does not identify the exact heparin-recognition residues, and family HSPG-dependent assays must not be relabeled as a purified CCN6–heparin experiment. The target assay and original IBD/tree/alignment remain unverified, explicitly separate from the retained curation judgment.

Summary: CCN6 suppresses proliferation-associated tumor growth in the tested breast-cancer context.

Reason: The complete original abstract describes full-length human WISP3 expression in patient-derived SUM149 cells, fewer soft-agar colonies and reduced xenograft growth. Retain the experimental annotation with curator deference, bounded to that context; the full original proliferation methods were not accessed. This is not a universal antiproliferative property across tissues.

Summary: CCN6 reduces angiogenic potential in the tested inflammatory breast-cancer system.

Reason: The original abstract explicitly reports lower angiogenic potential after human WISP3 transfection and reduced tumor growth in nude mice. Retain the curated experimental process as a contextual outcome. The complete angiogenesis protocol and the responsible extracellular effector were not inspected, so this does not establish a general endothelial inhibitor activity.

Summary: Broad extracellular-matrix association is retained as a contextual inherited location.

Reason: The broad PAINT matrix association is compatible with the matricellular family context and extracellular ligand regulation. The target in the source list is legitimate descendant evidence, not circularity. Retain the inherited broad location with curator deference while distinguishing it from the more precise, unresolved non-collagenous interstitial solid-phase assertions below. The original IBD placement and matrix-localization experiments were not inspected.

Summary: Retain inherited positive regulation of differentiation as a non-core, cell-state-dependent role.

Reason: The positive ancestral assertion at PTN000142750 is retained with curator deference. CCN-family primary experiments include promotion and restoration of chondrocyte differentiation, while other family members and cellular states show opposing effects; the family therefore cannot be assigned a universal direction from architecture alone. Human CCN6 inhibition of IGF1-driven hypertrophy and of BMP-induced alkaline-phosphatase responses does not demonstrate loss of every positive differentiation role. Those target experiments are not positive-differentiation assays, and cartilage disease alone is not used as one. Retain the existing broad inherited role as non-core while the responsible target cell state and original IBD evidence remain unresolved.

Summary: CCN6-dependent growth-factor regulation contributes to developmental and tissue-maintenance outcomes.

Reason: Retain this broad process as non-core in light of target ligand-regulation experiments and the documented cartilage disorder. Human postnatal cartilage homeostasis, zebrafish developmental phenotypes and mouse observations are distinct evidence contexts; the ARBA rule logic was not inspected and no specific embryonic process is added.

Summary: CCN6 depletion alters mitochondrial-potential-associated readouts in human chondrocytes.

Reason: The original human C-28/I2 siRNA study reports increased potential-sensitive dye signals with increased mitochondrial mass, respiration and ROS. Its externally read Methods identify the dye and depletion controls; these are cellular regulatory measurements, not intrinsic CCN6 proton-pumping chemistry. Retain the nondirectional process as non-core and do not generalize the chondrocyte direction to mammary cells.

Summary: The precise interstitial-matrix location remains unverified for human CCN6.

Reason: The complete canonical PMID:23825719 narrative introduces the CCN family but focuses its experimental discussion on CCN1 in retinal systems; no target-specific CCN6 interstitial solid-phase localization assay was identified in that inspected narrative. GO:0140149 concerns non-collagenous material in the interstitial extracellular matrix, which is more specific than secretion. This is an explicit source-scope uncertainty, not a title-only wrong-paralog claim or evidence that a nonstructural regulator cannot reside in matrix.

Summary: The electronic precise interstitial-matrix assignment needs its actual rule and donor evidence.

Reason: GO_REF:0000120 combines several electronic pipelines. ARBA00096895, D3Z5L9 and ENSMUSP00000076003 are preserved exactly, but their underlying target-term evidence could not be recovered in the bounded consultation. Broad extracellular or inherited matrix association does not independently settle this precise location. No taxonomic exclusion or negative localization claim is made.

Summary: CCN6 perturbation regulates mitochondrial ROS production in a context-dependent manner.

Reason: The human chondrocyte siRNA experiment reports increased mitochondrial ROS alongside increased respiratory activity. Independent mammary-cell work shows that CCN6 effects on respiration and ROS can differ by cell context. Retain the nondirectional regulatory process as non-core; neither perturbation nor mitochondrial coassociation identifies CCN6 as an oxidoreductase or a stoichiometric respiratory-complex component.

Summary: Human CCN6 binds IGF-I with weak affinity in the tested recombinant-protein system.

Reason: PMID:23424195 tests IGF1, so GO:0031994 is the specific child of insulin-like growth factor binding supported by this IPI assertion. Recombinant-protein coimmunoprecipitation and SPR establish binding; the reported affinity is approximately 30 micromolar for immobilized WISP3, not the high affinity of canonical IGFBPs. The isolated IGFBP-like domain is insufficient for full binding. Deletion of the GCGCC motif does not abolish interaction, whereas the poorly expressed GLYC-deletion construct was not interpretable as a binding test. Cell-based association and response controls complement these assays. Separate human WISP3/mouse BMP4 conditioned-medium coassociation is not evidence for the IGF1-only row and is not added as another NEW assertion. Official definition/parents, positive IGFBP2/IGFBP3/IGFBP5 comparator coverage and the local GO-CAM index were checked; the parent growth-factor-binding proposal is replaced, not duplicated.