Anatomy of the Platelet Cytoskeleton

The platelet cytoskeleton maintains the discoid shape of the resting platelet and mediates a rapid shape change in response to external stimuli at sites of vascular injury. At rest, specific cytoskeletal structures and molecules maintain the unique architecture of the platelet actin cytoskeleton, connect it to the plasma membrane, and prevent actin monomer assembly onto actin filaments. Platelet activation stimulates the interactions of cytoplasmic signals with actin regulatory proteins to initiate and amplify actin filament growth necessary for platelet shape change. This chapter reviews the cellular mechanisms and proteins maintaining the morphology of resting and activated platelets, focusing on the actin cytoskeleton and exciting recent mRNA and protein profiling studies, clinical observations, and mouse models.