scholarly journals GIV•Kindlin interaction is required for Kindlin-Mediated Integrin Recognition and Activation

2019 ◽  
Author(s):  
Cristina Rohena ◽  
Nicholas Kalogriopoulos ◽  
Navin Rajapakse ◽  
Suchismita Roy ◽  
Inmaculada Lopez-Sanchez ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Cell Adhesion ◽  
Cancer Metastasis ◽  
List Type ◽  
Β1 Integrin ◽  
Nucleotide Exchange ◽  
Integrin Activation ◽  
Tumor Cell Adhesion ◽  
Linear Motif ◽  
C Terminus

ABSTRACTCells perceive and respond to the extracellular matrix (ECM) via integrin receptors; their dysregulation has been implicated in inflammation and cancer metastasis. Here we show that a guanine nucleotide exchange modulator of trimeric-GTPase Gαi, GIV (a.k.a Girdin), directly binds the integrin adaptor Kindlin-2. A non-canonical short linear motif within GIV’s C-terminus binds Kindlin-2-FERM3 domain at a site that is distinct from the binding site for the canonical NPxY motif on the -integrin tail. Binding of GIV to Kindlin-2 allosterically enhances Kindlin-2’s affinity for β1-integrin. Consequently, integrin activation and clustering are maximized, which augments cell adhesion, spreading and invasion. Findings elucidate how the GIV•Kindlin-2 complex has a two-fold impact: it allosterically synergizes integrin activation and enables β1-integrins to indirectly access and modulate trimeric GTPases via the complex. Furthermore, Cox proportional-hazard models on tumor transcriptomics provide trans-scale evidence of synergistic interactions between GIV•Kindlin-2•β1-integrin on time to progression to metastasis.The eTOC blurbIntegrins mediate cell adhesion to the extracellular matrix; their dysregulation fuels inflammation, cancer cell invasion and metastasis. Authors show how two pro-metastatic scaffold proteins, Kindlin and GIV/Girdin bind and cooperatively enhance their allosteric coupling to integrins, and their subsequent activation. Findings reveal novel interfaces in integrin signaling for pharmacologic manipulation.HIGHLIGHTSGIV and Kindlin(K2), two integrin adaptors that promote metastasis, bind each otherBinding of GIV or integrin to K2 allosterically enhances GIV•K2•integrin complexesBinding is required for the maximal recruitment of GIV and K2 to active integrinsBinding facilitates integrin clustering, activation, tumor cell adhesion, invasion.

ROLE OF PLATELET GLYCOPROTEINS lb AND llb/llla IN TUMOR CELL INDUCED PLATELET AGGREGATION AND TUMOR CELL ADHESION TO EXTRACELLULAR MATRIX. I. Grossi

1987 ◽  
Author(s):  
L Grossi ◽  
K V Honn ◽  
B F Sloane ◽  
J Thomopson ◽  
D Ohannesian ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Cell Adhesion ◽  
Platelet Aggregation ◽  
Tumor Cell ◽  
Platelet Adhesion ◽  
Eicosatetraenoic Acid ◽  
Platelet Glycoprotein ◽  
Dependent Manner ◽  
Tumor Cell Adhesion ◽  
Dose Dependent

Platelet glycoproteins are known to play a role in platelet platelet interactions, platelet activation, and platelet adhesion to extracellular matrix (ECM). Monoclonal antibody to human platelet glycoprotein lb (mAblb) and polyclonal antibodies to the llb/llla complex (pAbllb/llla) were used to evaluate the involvement of these glycoproteins in tumor cellinduced platelet aggregation (TCIPA and tumor cell adhesion to the ECM. We have demonstrated that human cervical carcinoma (MS5I7), human colon carcinoma (Clone A), and rat Walker 256 carcinosarcoma (W256) cells induce aggregation of homologous platelets via thrombin generation. MAblb and pAbllb/llla were shown to inhibit TCIPA by MS517, Clone A, and W256 in a dose dependent manner. MAblb was also shown to inhibit platelet thromboxane B2 production in response to tumor cells in a dose dependent manner. Neither mAblb nor pAbllb/llla had any effect on ADP stimulated platelet aggregation. Concentrations of mAblb and pAbllb/llla which produced half maximal inhibition alone were combined resulting in complete inhibition of TCIPA. Preincubation of MS5I7 and W256 with mAblb also resulted in inhibition of TCIPA, while preincubation of Clone A with mAblb did not, suggesting the presence of this glycoprotein on the cell membranes of MS5I7 and W256, but not on Clone A. Immunofluorescence studies confirmed the presence of this glycoprotein on the cell plasma membrane of the MS5I7 and W256, but not on Clone A. Preincubation of MS5I7 and W256 with both mAblb and pAbllb/llla alone or in combination, also resulted in decreased (12S)-12 -hydroxy -5, 8,10, 14 -eicosatetraenoic acid (12-HETE) production, while platelets preincubated with these antibodies had no effect on the concentration of 12-HETE produced. Isolation of platelet membranes and released platelet contentswere tested separately and in combination on platelet adhesion to ECM. Platelet release factors were ineffective, while isolated platelet membrane ghosts enhanced adhesion. Disruption of the platelet cytoskeleton andinhibition of the formation of the llb/llla complex decreased platelet enhanced tumor cell adhesion. These findings suggest a role for these platelet glycoproteins in TCIPA, platelet enhanced tumor cell adhesion to ECM and subsequent tumor metastasis.

scholarly journals Recreation of the terminal events in physiological integrin activation

2010 ◽  
Vol 188 (1) ◽  
pp. 157-173 ◽  
Author(s):  
Feng Ye ◽  
Guiqing Hu ◽  
Dianne Taylor ◽  
Boris Ratnikov ◽  
Andrey A. Bobkov ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Cell Adhesion ◽  
Integrin Signaling ◽  
Integrin Activation ◽  
Matrix Assembly ◽  
Integrin Αiibβ3 ◽  
Terminal Events ◽  
Cell Adhesion And Migration ◽  
And Migration

Increased affinity of integrins for the extracellular matrix (activation) regulates cell adhesion and migration, extracellular matrix assembly, and mechanotransduction. Major uncertainties concern the sufficiency of talin for activation, whether conformational change without clustering leads to activation, and whether mechanical force is required for molecular extension. Here, we reconstructed physiological integrin activation in vitro and used cellular, biochemical, biophysical, and ultrastructural analyses to show that talin binding is sufficient to activate integrin αIIbβ3. Furthermore, we synthesized nanodiscs, each bearing a single lipid-embedded integrin, and used them to show that talin activates unclustered integrins leading to molecular extension in the absence of force or other membrane proteins. Thus, we provide the first proof that talin binding is sufficient to activate and extend membrane-embedded integrin αIIbβ3, thereby resolving numerous controversies and enabling molecular analysis of reconstructed integrin signaling.

scholarly journals Biologically Active TNIIIA2 Region in Tenascin-C Molecule: A Major Contributor to Elicit Aggressive Malignant Phenotypes From Tumors/Tumor Stroma

2020 ◽  
Vol 11 ◽  
Author(s):  
Takuya Iyoda ◽  
Motomichi Fujita ◽  
Fumio Fukai
Keyword(s):  
Cell Adhesion ◽  
Tumor Stroma ◽  
Biologically Active ◽  
Migration And Invasion ◽  
Β1 Integrin ◽  
Integrin Activation ◽  
Type Iii ◽  
Fibronectin Type Iii ◽  
A2 Domain ◽  
Fibronectin Type

Tenascin (TN)-C is highly expressed specifically in the lesions of inflammation-related diseases, including tumors. The expression level of TN-C in tumors and the tumor stroma is positively correlated with poor prognosis. However, no drugs targeting TN-C are currently clinically available, partly because the role of TN-C in tumor progression remains controversial. TN-C harbors an alternative splicing site in its fibronectin type III repeat domain, and its splicing variants including the type III-A2 domain are frequently detected in malignant tumors. We previously identified a biologically active region termed TNIIIA2 in the fibronectin type III-A2 domain of TN-C molecule and showed that this region is involved in promoting firm and persistent cell adhesion to fibronectin. In the past decade, through the exposure of various cell lines to peptides containing the TNIIIA2 region, we have published reports demonstrating the ability of the TNIIIA2 region to modulate distinct cellular activities, including survival/growth, migration, and invasion. Recently, we reported that the signals derived from TNIIIA2-mediated β1 integrin activation might play a crucial role for inducing malignant behavior of glioblastoma (GBM). GBM cells exposed to the TNIIIA2 region showed not only exacerbation of PDGF-dependent proliferation, but also acceleration of disseminative migration. On the other hand, we also found that the pro-inflammatory phenotypic changes were promoted when macrophages are stimulated with TNIIIA2 region in relatively low concentration and resulting MMP-9 upregulation is needed to release of the TNIIIA2 region from TN-C molecule. With the contribution of TNIIIA2-stimulated macrophages, the positive feedback spiral loop, which consists of the expression of TN-C, PDGF, and β1 integrin, and TNIIIA2 release, seemed to be activated in GBM with aggressive malignancy. Actually, the growth of transplanted GBM grafts in mice was significantly suppressed via the attenuation of β1 integrin activation. In this review, we thus introduce that the TNIIIA2 region has a significant impact on malignant progression of tumors by regulating cell adhesion. Importantly, it has been demonstrated that the TNIIIA2 region exerts unique biological functions through the extremely strong activation of β1-integrins and their long-lasting duration. These findings prompt us to develop new therapeutic agents targeting the TNIIIA2 region.

scholarly journals Filamin A is required for vimentin-mediated cell adhesion and spreading

2010 ◽  
Vol 298 (2) ◽  
pp. C221-C236 ◽  
Author(s):  
Hugh Kim ◽  
Fumihiko Nakamura ◽  
Wilson Lee ◽  
Yulia Shifrin ◽  
Pamela Arora ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Cell Adhesion ◽  
Protein Kinase ◽  
Cell Spreading ◽  
Intermediate Filament Protein ◽  
Β1 Integrin ◽  
Filamin A ◽  
Integrin Activation ◽  
Hek 293 ◽  
Kinase C

Cell adhesion and spreading are regulated by complex interactions involving the cytoskeleton and extracellular matrix proteins. We examined the interaction of the intermediate filament protein vimentin with the actin cross-linking protein filamin A in regulation of spreading in HEK-293 and 3T3 cells. Filamin A and vimentin-expressing cells were well spread on collagen and exhibited numerous cell extensions enriched with filamin A and vimentin. By contrast, cells treated with small interfering RNA (siRNA) to knock down filamin A or vimentin were poorly spread; both of these cell populations exhibited >50% reductions of cell adhesion, cell surface β1 integrin expression, and β1 integrin activation. Knockdown of filamin A reduced vimentin phosphorylation and blocked recruitment of vimentin to cell extensions, whereas knockdown of filamin and/or vimentin inhibited the formation of cell extensions. Reduced vimentin phosphorylation, cell spreading, and β1 integrin surface expression, and activation were phenocopied in cells treated with the protein kinase C inhibitor bisindolylmaleimide; cell spreading was also reduced by siRNA knockdown of protein kinase C-ε. By immunoprecipitation of cell lysates and by pull-down assays using purified proteins, we found an association between filamin A and vimentin. Filamin A also associated with protein kinase C-ε, which was enriched in cell extensions. These data indicate that filamin A associates with vimentin and to protein kinase C-ε, thereby enabling vimentin phosphorylation, which is important for β1 integrin activation and cell spreading on collagen.

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