Threonine 788 in integrin subunit β1 regulates integrin activation

Nilsson, Stina; Kaniowska, Dorota; Brakebusch, Cord; Fässler, Reinhard; Johansson, Staffan

doi:10.1016/j.yexcr.2005.12.001

Cited by 28 publications

(38 citation statements)

References 47 publications

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“…Moreover, ␤ 1A -T788D substitution, mimicking a phosphorylated residue, significantly enhanced GD25-␤ 1A,T788D cell adhesion. Taken together with recent work by Nilsson et al (43), showing that ␤ 1A -T789A substitution has little effect on cell adhesion, these results suggest that T788 phosphorylation holds the greater regulatory importance of the two residues.…”

Section: Discussionsupporting

confidence: 79%

“…␤ 1 -Integrin S785 phosphorylation has been shown to regulate localization to focal adhesions (1) and enhance cell attachment but to inhibit cell spreading and migration (40). Replacement of both T788 and T789 in ␤ 1 -integrin with alanine residues disrupts fibroblast attachment to fibronectin and significantly reduces exposure of the ␤ 1 -integrin conformational activation epitope 9EG7 (70), whereas introduction of a T788D substitution, mimicking phosphorylation, results in a constitutively active conformation, 9EG7 induction, and enhanced cell adhesion (43). Interestingly, loss of ligand-binding function associated with double TT788/9AA substitutions does not affect induction of focal adhesion kinase (FAK) phosphorylation by ␤ 1 -antibody-mediated receptor cross-linking, suggesting that T788/9 phosphorylation is involved in "inside-out" signaling rather than "outside-in" (70).…”

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confidence: 99%

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Increased extracellular pressure enhances cancer cell integrin-binding affinity through phosphorylation of β₁-integrin at threonine 788/789

Craig¹,

Gayer²,

Schaubert³

et al. 2009

American Journal of Physiology-Cell Physiology

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. Increased extracellular pressure enhances cancer cell integrin-binding affinity through phosphorylation of ␤1-integrin at threonine 788/789. Am J Physiol Cell Physiol 296: C193-C204, 2009. First published November 12, 2008 doi:10.1152/ajpcell.00355.2008.-Increased extracellular pressure stimulates ␤1-integrin-dependent cancer cell adhesion. We asked whether pressure-induced adhesion is mediated by changes in ␤1-integrin binding affinity or avidity and whether these changes are phosphorylation dependent. We evaluated integrin affinity and clustering in human SW620 colon cancer cells by measuring differences in binding between soluble Arg-Gly-Asp (RGD)-Fc ligands and RGD-Fc-F(abЈ)2 multimeric complexes under ambient and 15-mmHg increased pressures. Phosphorylation of ␤1-integrin S785 and T788/9 residues in SW620 and primary malignant colonocytes was assessed in parallel. We further used GD25-␤1-integrin-null murine fibroblasts stably transfected with either wild-type ␤1A-integrin, S785A, TT788/9AA, or T788D mutants to investigate the role of ␤1-integrin site-specific phosphorylation. SW620 binding of RGD-Fc-F(abЈ)2 multimeric complexes, but not soluble RGD-Fc ligands, was sensitive to integrin clustering. RGD-Fc ligand binding was significantly increased under elevated pressure, suggesting that pressure modulates ␤1-integrin affinity. Pressure stimulated both ␤1-integrin S785 and T788/9 phosphorylation. GD25-␤1A-integrin wild-type and S785A cells displayed an increase in adhesion to fibronectin under elevated pressure, an effect absent in ␤1-integrin-null and TT788/9AA cells. T788D substitution significantly elevated basal cell adhesion but displayed no further increase under pressure. These results suggest pressure-induced cell adhesion is mediated by ␤1-integrin T788/9 phosphorylation-dependent changes in integrin binding affinity. adhesion; mechanotransduction; metastasis INTEGRIN-MEDIATED TUMOR CELL adhesion to extracellular matrix components or endothelial cells is an important step in the development of metastatic lesions. Integrin binding affinity is regulated by distinct receptor activation states (23). Initial cell attachment requires integrin activation by cytoplasmic signals that convey large conformational changes to the extracellular domain and enhance ligand-binding affinity (56). The avidity and strength of the interaction is further increased through the redistribution of integrins in the cell membrane, often referred to as receptor clustering (65). The tendency of some malignancies to exhibit reduced integrin expression while maintaining adhesive properties underscores the significance of integrin activation states in mediating tumor cell adhesion (33, 47).Likewise, mutations conferring constitutive integrin activation have been shown to directly contribute to the metastatic potential of cancer cells (20,53). Mechanisms underlying integrin affinity and avidity modulation are therefore of significant interest in the control of tumor metastasis.It is increasingly clear that integrin modulation may...

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Section: Discussionsupporting

confidence: 79%

mentioning

confidence: 99%

Increased extracellular pressure enhances cancer cell integrin-binding affinity through phosphorylation of β₁-integrin at threonine 788/789

Craig¹,

Gayer²,

Schaubert³

et al. 2009

American Journal of Physiology-Cell Physiology

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“…Depletion of tetraspanin CD82 also did not diminish surface expression of CD151 or integrin subunits. Furthermore, the percentage of b1 integrin expressing the 9EG7 neoepitope [sometimes associated with integrin activation (Nilsson et al, 2006)] was also not decreased (9.9% increased to 11.5%; supplementary material Fig. S2).…”

Section: Cd151 Affects Cell Cable Formation and Adhesionmentioning

confidence: 95%

CD151 restricts α6 integrin diffusion mode

Yang

Mirchev

Deng

et al. 2012

Journal of Cell Science

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SummaryLaminin-binding integrins (a3b1, a6b1, a6b4, a7b1) are almost always expressed together with tetraspanin CD151. In every coexpressing cell analyzed to date, CD151 makes a fundamental contribution to integrin-dependent motility, invasion, morphology, adhesion and/or signaling. However, there has been minimal mechanistic insight into how CD151 affects integrin functions. In MDA-MB-231 mammary cells, tetraspanin CD151 knockdown impairs a6 integrin clustering and functions without decreasing a6 integrin expression or activation. Furthermore, CD151 knockdown minimally affects the magnitude of a6 integrin diffusion, as measured using single particle tracking. Instead, CD151 knockdown has a novel and unexpected dysregulating effect on the mode of a6 integrin diffusion. In control cells a6 integrin shows mostly random-confined diffusion (RCD) and some directed motion (DMO). In sharp contrast, in CD151-knockdown cells a6 integrin shows mostly DMO. In control cells a6 diffusion mode is sensitive to actin disruption, talin knockdown and phorbol ester stimulation. By contrast, CD151 knockdown cell a6 integrin is sensitive to actin disruption but desensitized to talin knockdown or phorbol ester stimulation, indicating dysregulation. Both phorbol ester and EGF stimulate cell spreading and promote a6 RCD in control cells. By contrast, CD151-ablated cells retain EGF effects but lose phorbol-ester-stimulated spreading and a6 RCD. For a6 integrins, physical association with CD151 promotes a6 RCD, in support of a6-mediated cable formation and adhesion. By comparison, for integrins not associated with CD151 (e.g. av integrins), CD151 affects neither diffusion mode nor av function. Hence, CD151 support of a6 RCD is specific and functionally relevant, and probably underlies diverse CD151 functions in skin, kidney and cancer cells.

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“…proper regulation of ␤1-integrin activation. ␤1-integrin has previously shown to be phosphorylated at intracellular tyrosine, serine, and threonine sites although the significance of the various phosphorylation sites appear to have different implications for adhesion and cell motility in different cell lines (72)(73)(74)(75)(76)(77)(78). Serine 785 has been shown to promote attachment to laminin in two different cell types (fibroblast and cancer cell lines) and to inhibit cell migration in these two cell lines (65).…”

Section: ␤1-integrin Phosphorylation Is Restored By Transient Transfementioning

confidence: 99%

α-Actinin-4 Is Required for Normal Podocyte Adhesion

Dandapani

Sugimoto

Matthews

et al. 2007

Journal of Biological Chemistry

115

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Mutations in the ␣-actinin-4 gene ACTN4 cause an autosomal dominant human kidney disease. Mice deficient in ␣-actinin-4 develop a recessive phenotype characterized by kidney failure, proteinuria, glomerulosclerosis, and retraction of glomerular podocyte foot processes. However, the mechanism by which ␣-actinin-4 deficiency leads to glomerular disease has not been defined. Here, we examined the effect of ␣-actinin-4 deficiency on the adhesive properties of podocytes in vivo and in a cell culture system. In ␣-actinin-4-deficient mice, we observed a decrease in the number of podocytes per glomerulus compared with wild-type mice as well as the presence of podocyte markers in the urine. Podocyte cell lines generated from ␣-actinin-4-deficient mice were less adherent than wild-type cells to glomerular basement membrane (GBM) components collagen IV and laminin 10 and 11. We also observed markedly reduced adhesion of ␣-actinin-4-deficient podocytes under increasing shear stresses. This adhesion deficit was restored by transfecting cells with ␣-actinin-4-GFP. We tested the strength of the integrin receptor-mediated linkages to the cytoskeleton by applying force to microbeads bound to integrin using magnetic pulling cytometry. Beads bound to ␣-actinin-4-deficient podocytes showed greater displacement in response to an applied force than those bound to wild-type cells. Consistent with integrin-dependent ␣-actinin-4-mediated adhesion, phosphorylation of ␤1-integrins on ␣-actinin-4-deficient podocytes is reduced. We rescued the phosphorylation deficit by transfecting ␣-actinin-4 into ␣-actinin-4-deficient podocytes. These results suggest that ␣-actinin-4 interacts with integrins and strengthens the podocyte-GBM interaction thereby stabilizing glomerular architecture and preventing disease.

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Threonine 788 in integrin subunit β1 regulates integrin activation

Cited by 28 publications

References 47 publications

Increased extracellular pressure enhances cancer cell integrin-binding affinity through phosphorylation of β₁-integrin at threonine 788/789

Increased extracellular pressure enhances cancer cell integrin-binding affinity through phosphorylation of β₁-integrin at threonine 788/789

CD151 restricts α6 integrin diffusion mode

α-Actinin-4 Is Required for Normal Podocyte Adhesion

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Threonine 788 in integrin subunit β1 regulates integrin activation

Cited by 28 publications

References 47 publications

Increased extracellular pressure enhances cancer cell integrin-binding affinity through phosphorylation of β1-integrin at threonine 788/789

Increased extracellular pressure enhances cancer cell integrin-binding affinity through phosphorylation of β1-integrin at threonine 788/789

CD151 restricts α6 integrin diffusion mode

α-Actinin-4 Is Required for Normal Podocyte Adhesion

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Increased extracellular pressure enhances cancer cell integrin-binding affinity through phosphorylation of β₁-integrin at threonine 788/789

Increased extracellular pressure enhances cancer cell integrin-binding affinity through phosphorylation of β₁-integrin at threonine 788/789