Structural analysis of receptors and actin polarity in platelet protrusions
Simona Sorrentino, José Javier Conesa, Ana Cuervo, Roberto Melero, Bruno Martins, E. Fernández-Giménez, F.P. de Isidro-Gómez, Jimenez de la Morena, Jan–Dirk Studt, Carlos Óscar S. Sorzano, Matthias Eibauer, J.M. Carazo, Ohad Medalia
Abstract
Significance Platelet activation induces reorganization of the cell and the formation of cellular protrusions, pseudopodia. These processes are accompanied by remodeling of the actin cytoskeleton and the activation of platelet integrins, which mediate strong adhesion to the extracellular matrix. In this work, we analyzed the actin polarity and integrin architecture in pseudopodia. A nonuniform polarity of actin filaments in pseudopodia indicates that these protrusions may be involved in contractile acto-myosin forces. Heterogeneity in integrin conformation was found, while solely a bent integrin structure was resolved, ∼50 to 70 nm above the support.