| 1991 |
The complete amino acid sequence of integrin β7 was determined from overlapping cDNA clones obtained from leukocyte libraries. The β7 protein is predicted to contain a large extracellular portion, a transmembrane domain, and a cytoplasmic tail, with 32–46% identity to other human integrin β subunits and closest similarity to β2 (CD18). β7 mRNA was detected in T and B cell lines and macrophage-like cell lines but not in non-leukocyte cell lines, and phorbol ester stimulation markedly increased β7 mRNA levels in peripheral T cells. |
cDNA cloning and sequencing, Northern blot analysis, reverse transcription-PCR |
The Journal of biological chemistry |
High |
2040612
|
| 1992 |
Integrin α4β7 (also called α4βP) was identified as the β7-containing heterodimer expressed in TK-1 T lymphoma cells and activated peripheral blood T cells. α4β7 functions as a fibronectin receptor that binds to the CS-1 region (not the RGD sequence) of fibronectin, and also supports adhesion to VCAM-1, both of which are markedly enhanced by PMA stimulation. Anti-α4 and anti-β7 antibodies induce homotypic cell clustering. |
Anti-peptide antiserum and mAb immunoprecipitation, affinity chromatography, cell adhesion assays, antibody blocking |
The Journal of cell biology |
High |
1372909
|
| 1992 |
A family of β7 integrins on human mucosal lymphocytes was characterized: the HML-1 antigen (αEβ7) and α4β7 both use the β7 chain. The HML-1 α-subunit was designated αE (a novel integrin α chain). TGF-β1 reciprocally regulated HML-1 (αEβ7) and LFA-1 expression. |
N-terminal protein sequencing of purified HML-1 subunit, biochemical characterization, immunoprecipitation |
Proceedings of the National Academy of Sciences of the United States of America |
High |
1542691
|
| 1992 |
On the JY B lymphoblastoid cell line expressing α4β7 without α4β1, α4β7 makes little or no contribution to fibronectin or VCAM-1 binding under basal conditions; a minor contribution emerges only after PMA stimulation. α4β1 is the functionally dominant VCAM-1 and fibronectin receptor. This demonstrated that the β subunit partner determines the adhesive specificity of α4 integrins. |
Northern blotting, immunoprecipitation, cell adhesion assays with blocking antibodies |
The Journal of biological chemistry |
High |
1373725
|
| 1993 |
α4β7 integrin was identified as the receptor for the mucosal vascular addressin MAdCAM-1. Antibodies to α4 and β7 (but not β2/LFA-1) inhibit lymphocyte binding to purified MAdCAM-1 and to MAdCAM-1 transfectants. Mn2+-induced integrin activation enhances binding. MAdCAM-1 is a preferential ligand for α4β7 over α4β1; α4β7 can also bind VCAM-1 but requires greater integrin activation. |
Antibody blocking assays, cell adhesion to purified MAdCAM-1 and transfectants, Mn2+ activation |
Cell |
High |
7687523
|
| 1993 |
α4β7 on human B lymphocytes mediates adhesion to fibronectin and VCAM-1 through distinct epitopes on the integrin. α4β7 expression is absent on resting lymphoid tissue B cells but induced upon activation. α4β7 also participates in homotypic B cell aggregation and co-clusters with α4β1 at fibronectin/VCAM-1-coated surfaces. |
Immunoprecipitation, cell adhesion assays, antibody blocking, flow cytometry |
Journal of immunology |
High |
7689608
|
| 1998 |
The β7 integrin gene promoter contains TGF-β1 response regions at nucleotides -509 to -398 (TGFBRR1) and -122 to +32 (TGFBRR2) that drive TGF-β1-induced gene expression. TGF-β1 increases β7 and αE subunit mRNA and M290 (αEβ7) surface expression on T cells while decreasing α4 transcripts. Induced β7 expression is inhibited by the tyrosine kinase inhibitor genistein. TGFBRR1 and TGFBRR2 interact with distinct nuclear protein complexes in a phosphorylation-dependent manner. |
Promoter-reporter deletion analysis, DNase I hypersensitivity mapping, gel-shift assays, RT-PCR, genistein inhibition |
Immunogenetics |
High |
9683663
|
| 2001 |
The β7 integrin cytoplasmic tail binds strongly to filamin A, and this tight filamin binding inhibits integrin-dependent cell migration by suppressing transient membrane protrusion and cell polarization. Amino acid substitutions that selectively ablate filamin binding from the β7 tail (or confer it onto β1A) confirm this mechanistic link: increased filamin binding correlates with reduced migration without affecting fibronectin matrix assembly or focal adhesion formation. |
Mutagenesis mapping of filamin-binding site, cell migration assays, membrane protrusion analysis |
Nature cell biology |
High |
11781567
|
| 2003 |
Integrin α4β7 adhesiveness is bistably regulated by a linear array of three divalent cation-binding sites in the β7 I-like domain: MIDAS is required for both rolling and firm adhesion; ADMIDAS (adjacent to MIDAS) negatively regulates via Ca2+ to permit rolling; LIMBS positively responds to low Ca2+ to promote firm adhesion. ADMIDAS mutation converts rolling to firm adhesion; LIMBS mutation converts firm adhesion to rolling. |
Site-directed mutagenesis of metal-binding sites, adhesion assays under defined ionic conditions (Ca2+, Mg2+, Mn2+) |
Nature structural biology |
High |
14608374
|
| 2003 |
Multiple PTB domain-containing proteins (talin, ICAP1-α, Numb, Dok-1) bind to the NPXY motifs in integrin β cytoplasmic tails via a conserved PTB domain–NPXY ligand interaction. β7 and β3 tail mutations of the NPXY motif block these interactions. Gain- and loss-of-function mutations in the β7 tail confirmed class-specific interactions with particular PTB domains (e.g., Dab, EPS8, tensin show integrin class-specific binding). |
Recombinant PTB domain binding to integrin tails, mutagenesis, molecular modeling, Co-immunoprecipitation |
Proceedings of the National Academy of Sciences of the United States of America |
High |
12606711
|
| 2003 |
Peyer's patch dendritic cells selectively imprint gut-homing specificity on T cells by inducing high levels of α4β7 (ITGB7-containing integrin) and CCR9, enabling small intestinal homing. This imprinting is specific to Peyer's patch DCs: peripheral lymph node and spleen DCs induced equivalent activation but did not upregulate α4β7 or gut-homing ability. |
T cell stimulation with DCs from different anatomical sites, flow cytometry for α4β7 expression, in vivo homing assays |
Nature |
High |
12840763
|
| 2007 |
αEβ7 (CD103/ITGB7) interaction with E-cadherin on tumor cells promotes antitumor CTL activity by recruiting αEβ7 to the immunological synapse and driving lytic granule polarization and exocytosis. Blocking anti-CD103 antibody or siRNA knockdown of E-cadherin abrogates tumor cell killing. TGF-β1 treatment of CD103- CTL clones upregulates αEβ7 and potentiates cytotoxicity. |
Antibody blocking, RNA interference, confocal microscopy of immunological synapse, cytotoxicity assays |
The Journal of experimental medicine |
High |
17325197
|
| 2007 |
Crystal structure of filamin A domains IgFLNa19-21 at 2.5 Å reveals auto-inhibition: the N-terminus of IgFLNa20 forms a β-strand that occupies the integrin β-tail binding site on IgFLNa21. Disrupting this auto-inhibitory IgFLNa20-IgFLNa21 interaction enhances filamin binding to integrin β-tails including β7. |
X-ray crystallography (2.5 Å), mutagenesis, integrin β-tail binding assays |
The EMBO journal |
High |
17690686
|
| 2008 |
HIV-1 envelope protein gp120 binds to activated α4β7 integrin via a tripeptide motif in the V2 loop of gp120 that mimics natural α4β7 ligands. Engagement of α4β7 by gp120 on CD4+ T cells rapidly activates LFA-1, facilitating formation of virological synapses for cell-to-cell HIV spreading. |
Binding assays with purified gp120 and α4β7, intracellular signaling assays, antibody blocking, flow cytometry |
Nature immunology |
High |
18264102
|
| 2009 |
α4β7high CD4+ T cells are more susceptible to productive HIV-1 infection than α4β7low/neg cells, partly because this subset is metabolically active, CCR5high and CXCR4low. On these cells, α4β7 appears in a complex with CD4, and gp120's specific affinity for α4β7 targets these cells. |
Flow cytometry, HIV infection assays, co-immunoprecipitation of α4β7 with CD4 |
Proceedings of the National Academy of Sciences of the United States of America |
High |
19933330
|
| 2009 |
Tyrosine phosphorylation of the β7 integrin cytoplasmic tail is a conserved mechanism for regulating integrin activation. Talin1 binds to the NPXY motif and membrane-proximal portion of β7 tail, and tyrosine phosphorylation decreases talin affinity while greatly increasing Dok1 affinity (restricted to the NPXY region). Dok1 acts as a talin competitor that does not form activating membrane-proximal interactions, thereby inhibiting integrin activation. |
NMR-based protein-protein interaction assay with 15N-labeled phosphorylated β7 tail, mutagenesis, talin1 D372R mutation and live cell localization |
The Journal of biological chemistry |
High |
19843520
|
| 2011 |
ITGB7 silencing in multiple myeloma (MM) cells reduces adhesion to fibronectin and E-cadherin, reverses cell-adhesion-mediated drug resistance to bortezomib and melphalan, abrogates SDF1α-driven transwell migration, reduces vessel density in xenografts, and alters in vivo BM homing. Mechanistically, ITGB7 knockdown inhibits FAK and Src phosphorylation, Rac1 activation and SUMOylation, reduces VEGF production in MM–BM stem cell co-cultures, and attenuates p65-NF-κB activity. |
shRNA knockdown, cell adhesion assays, transwell migration, in vivo xenograft and homing assays, Western blotting for FAK/Src/Rac1/NF-κB |
Blood |
High |
21474670
|
| 2011 |
Mechanical strain in actin networks differentially regulates binding of β-integrin cytoplasmic tails and FilGAP to filamin A (FLNA). Strain increases β-integrin tail binding to FLNA while causing FilGAP to dissociate, providing a direct molecular basis for mechanotransduction. The β7 integrin tail was used in the reconstituted minimal system (actin + FLNA + β-integrin tail + FilGAP). |
In vitro reconstitution with purified components, fluorescence loss after photoconversion, rheological measurement of actin network strain |
Nature |
High |
21926999
|
| 2020 |
In pancreatic cancer, TRIM2 activates NRF2 via ROS signaling, and NRF2 directly binds to an antioxidant response element (ARE) in the ITGB7 promoter to enhance ITGB7 transcription. ITGB7 in turn activates the FAK pathway. Antioxidant N-acetyl-L-cysteine treatment reduces ROS, NRF2, and ITGB7 levels; NRF2 nuclear translocation rescues inhibited ITGB7 transcription. |
siRNA/shRNA knockdown, NAC antioxidant treatment, promoter-reporter assay, ChIP-like NRF2 binding to ARE, Western blotting, in vivo tumorigenicity assays |
Oncogene |
Medium |
32929153
|
| 2019 |
Recombinant HPV16 capsid protein L2 (rVL2) suppresses glucose metabolism in cervical cancer cells by inhibiting the ITGB7/C/EBPβ signaling pathway, reducing expression of GLUT1, LDHA, and ALDOA. Inhibition of ITGB7 mediates rVL2-induced decreases in glucose uptake and lactate production, and consequent inhibition of proliferation. |
Gene-chip assay, RT-PCR, Western blot, glucose uptake and lactate production assays, in vivo animal model |
OncoTargets and therapy |
Medium |
31819523
|
| 2008 |
In the pregnant mouse uterus, ITGB7-positive decidual leukocytes are predominantly dendritic cells forming three phenotypically distinct subsets defined by differential expression of ITGA4/ITGB7 vs. ITGAE/ITGB7. These subsets reside in distinct uterine microdomains: ITGA4/ITGB7+ DCs localize to the vascular zone and make direct contact with uterine NK cells, while ITGAE/ITGB7+ DCs localize to the central decidua basalis and myometrium. |
Multiparameter flow cytometry, confocal microscopy |
Biology of reproduction |
Medium |
18562709
|