Cytoskeletal Proteins

The cytoskeleton represents the intricate inner carcass that stabilizes the cell by a network of three major components: microfilaments, microtubules, and intermediate filaments. This network is anchored to the membrane by highly specialized protein complexes, providing both cell attachment to other cells or extracellular matrices, as well as stabilization and dynamic rearrangement of cell-surface structures. Not only does the cytoskeleton maintain cell shape but it also manages compartmentalization and proper orientation of many biochemical processes including signal transduction. Cytoskeletal remodeling is critical for cell contraction, motility, and morphogenesis; in addition, the cytoskeleton serves as a cellular mechanosensor and mechanotransducer. Signals originating from cytoskeletal elements control gene expression, cell differentiation, proliferation, and survival. The vast majority of physiological responses, such as leukocyte migration and phagocytic activity, the ability of fibroblasts to heal wounds, angiogenesis, control over vascular/bronchial tone, and regulation of endothelial/epithelial barrier function depend upon cytoskeletal proteins, involved in the organization of intercellular contacts, and contractile proteins, inducing tension. Maintenance of barrier function is of particular importance in lung physiology, since an increase in alveolar capillary permeability and resultant edema represent the underlying causes of lung damage characterized as acute lung injury or acute respiratory distress syndrome. Different therapeutic strategies counteracting hyperpermeability are currently under development; some of which target signaling pathways, leading to cytoskeletal rearrangement.