Integrins are heterodimeric transmembrane receptors composed of α and β chains, with an N-terminal extracellular domain forming a globular head corresponding to the ligand binding site. Integrins ...regulate various cellular functions including adhesion, migration, proliferation, spreading and apoptosis. On platelets, integrins play a central role in adhesion and aggregation on subendothelial matrix proteins of the vascular wall, thereby ensuring hemostasis. Platelet integrins belong either to the β1 family (α2β1, α5β1 and α6β1) or to the β3 family (αIIbβ3 and αvβ3). On resting platelets, integrins can engage their ligands when the latter are immobilized but not in their soluble form. The effects of various agonists promote an inside-out signal in platelets, increasing the affinity of integrins for their ligands and conveying a modest signal reinforcing platelet activation, called outside-in signaling. This outside-in signal ensures platelet adhesion, shape change, granule secretion and aggregation. In this review, we examine the role of each platelet integrin in hemostatic plug formation, hemostasis and arterial thrombosis and also beyond these classical functions, notably in tumor metastasis and sepsis.
Managers play a vital role in encouraging and supporting the initiatives of individual employees to explore new opportunities, to develop new products or to improve work procedures for the benefit of ...the organization. This study examines the influence of manager leadership styles on employee intrapreneurial behavior and the mediating role of organizational identification. Partial Least Squares modeling was used to analyze the data from 186 employees belonging to several Spanish public and private organizations. The results show that transformational leadership has a positive impact on employee intrapreneurial behavior, whereas transactional leadership negatively influences it. Furthermore, these effects are found to be partially mediated by organizational identification.
Fibrin, the coagulation end product, consolidates the platelet plug at sites of vascular injury and supports the recruitment of circulating platelets. In addition to integrin αIIbβ3, another ...as-yet-unidentified receptor is thought to mediate platelet interaction with fibrin. Platelet glycoprotein VI (GPVI) interacts with collagen and several other adhesive macromolecules. We evaluated the hypothesis that GPVI could be a functional platelet receptor for fibrin. Calibrated thrombin assays using platelet-rich plasma (PRP) showed that tissue factor–triggered thrombin generation was impaired in GPVI-deficient patients and reduced by the anti-GPVI Fab 9O12. Assays on reconstituted PRP and PRP from fibrinogen-deficient patients revealed a fibrinogen-dependent enhancement of thrombin generation, which relied on functional GPVI. The effect of GPVI was found to depend on fibrin polymerization. A binding assay showed a specific interaction between GPVI-Fc and fibrin, inhibited by the Fab 9O12. This Fab also reduced platelet adhesion to fibrin at low (300 s−1) and high (1500 s−1) wall shear rates. Platelets adherent to fibrin displayed shape change, exposure of procoagulant phospholipids, and the formation of small clots. When hirudinated blood was perfused at 1500 s−1 over preformed fibrin-rich clots, the Fab 9O12 decreased the recruitment of platelets by up to 85–. This study identifies GPVI as a platelet receptor for polymerized fibrin with 2 major functions: (1) amplification of thrombin generation and (2) recruitment of circulating platelets to clots. These so-far-unrecognized properties of GPVI confer on it a key role in thrombus growth and stabilization.
•GPVI interaction with polymerized fibrin triggers a new loop amplifying thrombin generation and platelet recruitment at the clot surface.
Platelets are small anucleated cell fragments that ensure the arrest of bleeding after a vessel wall injury. They are also involved in non-hemostatic function such as development, immunity, ...inflammation, and in the hematogeneous phase of metastasis. While the role of platelets in tumor metastasis has been recognized for 60 years, the molecular mechanism underlying this process remains largely unclear. Platelets physically and functionally interact with various tumor cells through surface receptors including integrins. Platelets express five integrins at their surface, namely α2β1, α5β1, α6β1, αvβ3, and αIIbβ3, which bind preferentially to collagen, fibronectin, laminin, vitronectin, and fibrinogen, respectively. The main role of platelet integrins is to ensure platelet adhesion and aggregation at sites of vascular injury. Two of these, α6β1 and αIIbβ3, were proposed to participate in platelet-tumor cell interaction and in tumor metastasis. It has also been reported that pharmacological agents targeting both integrins efficiently reduce experimental metastasis, suggesting that platelet integrins may represent new anti-metastatic targets. This review focuses on the role of platelet integrins in tumor metastasis and discusses whether these receptors may represent new potential targets for novel anti-metastatic approaches.
•The results show low switching costs in the mobile services sector.•Mobile providers should focus their efforts toward attracting new customers.•Mobile providers should not focus on retaining ...existing customers.•Service value and corporate image are the key variables for customer satisfaction.•There is a lack of switching costs for traditional mobile services.
The present study analyses the creation of customer satisfaction and loyalty, along with the influence of switching costs in the mobile services’ market by comparing network – the so-called traditional – and virtual mobile services, in order to empirically and conceptually investigate the difference between these mobile services’ operators.
For this purpose we tested a conceptual model by developing structural equation modeling, in the context of a mature market– Spain– gathering a sample of 406 mobile phone users. The analysis highlights that both service value and corporate image exert the strongest influence on customer satisfaction and loyalty both for traditional and virtual mobile services, despite some relevant differences were found regarding switching costs. Since our findings show low switching costs, mobile service providers should focus their marketing efforts toward attracting new customers and increasing the primary demand, rather than retaining their existing customers.
The circular economy strategy supports the transformation of the linear consumption model into a closed-production model to achieve economic sustainability, with the consumers' acceptance of circular ...products being one of the major challenges. Further, one important aspect of product circularity remains unexplored, such as the consumers' purchase intention of recycled circular goods. In this context, the present study proposes and tests a conceptual model on consumers acceptance of recycled goods through PLS Structural Equation Modeling (PLS-SEM), based on the data obtained from 312 respondents. Results indicate that the positive image of circular products is the most important driver of consumers' acceptance, followed by the product perceived safety. This study provides an empirical foundation for the important role of consumers in circular economy business models through the examination of consumers' acceptance of recycled goods.
Shopping malls are facing times of hardship due to the recent economic crisis, the maturity of this retailing format and the increasing competition of the electronic commerce. This study aims to ...examine and profile shopping mall customer segments, since this context of hardship may have altered the previous mall customer segmentations.Data from 511 shopping mall customers in a mature market and during a recessionary period was analyzed through two-step cluster analysis and a subsequent MANOVA.Results suggest that mall customer segments are no longer so in hard times; and five segments emerge, namely “senior hostelry seekers”, “young enthusiasts”, “deal hunters”, “adverse-reluctant customers” and “leisure comfy-teens”; being the “young enthusiasts” the most attractive segment; while the “adverse-reluctant customers” represent the main challenge for mall managers.
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