The gene was discovered as a yeast two-hybrid hit against the isolated SH3 domain of Nesh (ABI3), from a human placenta library. This is the origin of the ABI3BP name, and the interaction was never shown for the full-length protein.

The clone described encodes 486 residues, which is exactly the length of UniProt isoform Q7Z7G0-2 - canonical 1068 residues minus the 1-607 deletion VSP_010860, plus the 25-residue insertion VSP_010861 at position 669. The two-hybrid interaction was therefore mapped only to the C-terminal third of the protein.

No catalytic domain, consistent with a purely non-enzymatic ligand role.

The alternative splicing of this gene is concentrated in a cluster of SH3-binding motifs in the middle of the coding sequence. In the human protein that region corresponds to the MobiDB-lite disordered segment 384-811, which carries 18 of the 21 PxxP motifs in the whole sequence.

Restoring ABI3BP in human thyroid carcinoma cell lines suppresses transformation, growth, viability, migration, invasion and xenograft tumour growth. This is the strongest human-cell evidence that ABI3BP restrains proliferation.

Gain of ABI3BP triggers p21-dependent senescence in human thyroid cancer cells - the opposite manipulation from PMID:19338757, reported to give the same outcome.

Direct demonstration that the protein is secreted, and identification of a distinct neuronal role: secreted TARSH reduces mitral cell dendritic complexity and restricts interneurone branching during postnatal olfactory refinement, with a cell-autonomous overexpression arm as well.

Expression is transient in mitral cells during the refinement window and is not altered by blocking odour-evoked activity, so the cue is developmentally programmed rather than activity-driven.

Knockdown in mouse embryonic fibroblasts inhibits proliferation and raises senescence-associated beta-galactosidase activity, p53- and p21-dependently. This is the opposite direction from the mesenchymal stem cell knockout of PMID:23666637, in which loss of the gene increases proliferation.

Stepwise biochemical fractionation was used to separate extracellular proteins from cellular and plasma contaminants in human aorta, and ABI3BP is among the proteins recovered. This is good evidence for the extracellular compartment and none for a structural role.

Integrin beta-1 is the ABI3BP receptor, and ligand binding suppresses proliferation through Src sequestration by phosphorylated paxillin.

The interaction was shown for endogenous protein, not only for a tagged construct, which is what makes it more than an overexpression artefact.

Receptor specificity was established with a blocking-antibody panel in which only the beta-1 antibody changed ERK signalling.

Loss of Abi3bp increases mesenchymal stem cell proliferation through cyclin-D1, ERK1/2 and Src.

Differentiation fails in knockout mesenchymal stem cells, which is the other half of the coupled proliferation/differentiation switch.

The mechanistic model, stated explicitly by the authors, makes ABI3BP a positive regulator of integrin beta-1 activation and a negative regulator of the ERK cascade.

The protein is deposited as discrete extracellular material, shown by antibody staining - non-proteomic support for the extracellular matrix cellular-component rows.

ABI3BP does not act by modulating growth-factor signalling, which is what pointed the authors to an integrin receptor and which distinguishes it from a diffusible growth factor.

The field itself records that the senescence literature for this gene is contradictory.

The ABI3 interaction that named the gene has never been confirmed for the full-length protein.

The only matrix-assembly observation about this protein concerns a fibronectin type-III fragment, reported here second-hand from PMID:18757743.

The mesenchymal stem cell switch generalises to cardiac progenitors in vivo: ablation expands the progenitor pool but blocks differentiation, and worsens recovery from myocardial infarction.

The same receptor, with PKC-zeta and Akt downstream in this lineage.

Receptor dependence was tested directly rather than inferred: blocking integrin beta-1 abolished the rescue by re-expressed Abi3bp.

ABI3BP is among the extracellular matrix proteins recovered from human saphenous vein wall by ECM proteomics, supporting the extracellular localisation in a third human tissue.

ABI3BP is recovered from the extracellular matrix of human atrial myocardium. The paper's own subject is decorin peptides; ABI3BP is an entry in the accompanying inventory.

This is a protocols paper. It supplies methods and web tools for ECM proteomics and illustrates them on breast and ovarian tissue pairs; it contains no ABI3BP-specific experiment and no measurement of matrix mechanics.

The tissues in which ABI3BP was detected under this protocol are breast and omental, which is what the accepted HDA cellular-component row rests on.

ABI3BP is down-regulated in human gallbladder cancer tissues and cell lines, reciprocally with MALAT1 - a third human tumour type in which loss of this gene accompanies transformation.

The database from which the GO_Central author statement assigning ABI3BP to the non-collagenous interstitial matrix compartment is drawn.

Knocking out ABI3BP raises Klotho and lowers ferroptosis in irradiated mouse kidney - one of three studies in which losing the gene reduces rather than increases senescence.

Overexpression in human non-small-cell lung cancer cells reduces growth and motility and arrests the cell cycle - human-cell corroboration of the growth-restraining function established mechanistically in mouse.

Silencing ABI3BP reduces angiotensin II-induced senescence in vascular smooth muscle cells, and knockout mice are protected from vascular ageing - the second of three studies in which losing the gene reduces senescence.

ABI3BP is elevated in human osteoarthritic cartilage, in a dataset whose enriched pathways are extracellular matrix organisation and ECM-receptor interaction. This adds cartilage to the interstitial matrix compartments in which the protein is found, and the ECM-receptor enrichment is consistent with a receptor-engaging rather than load-bearing role.

Knockdown reduces senescence markers in chondrocytes - the third study in which losing the gene reduces senescence.

Thrombin cleaves ABI3BP at arginine 337. The site is independently plausible: residue 337 of the canonical human sequence is arginine and its context is Pro-336/Arg-337/Ser-338, a canonical thrombin motif, and it lies in the disordered linker between the two fibronectin type-III domains.

Machine-generated summary of the gene as a secreted matrix protein restraining stem and progenitor proliferation while licensing differentiation. Used only as a pointer to the primary literature; the substance is carried by PMID:23666637 and PMID:25296984.

Secreted, with a signal peptide at residues 1-21 and a mature chain 22-1068. This is the source of the GO:0005576 IEA row via the SL-0243 keyword.

The ABI3 interaction that gives the gene its name is hedged by UniProt itself, consistent with it never having been shown for the full-length protein.

No PAINT/PAN-GO annotation exists for this protein, which is why the record contains no IBA row despite PANTHER family PTHR23197 subfamily SF10 being assigned to it.

Two fibronectin type-III domains, at 116-214 and 833-926, separated by a large disordered proline-rich region; no catalytic domain anywhere in the sequence.

The protein is detected at protein level, so the total absence of biological-process annotation is a curation gap rather than a reflection of an uncharacterised gene product.