[The cytoskeleton of platelets]

The platelet cytoskeleton is composed of microfilaments, microtubules and intermediate filaments (vimentin is only a minor component). Since actin is the major platelet protein, this review is restricted to aspects of the microfilamental system. The first part is devoted to the description of actin and of proteins thought to be associated with actin in platelets. The review will then focus on the organization of the microfilaments in unstimulated and stimulated platelets. Finally, the role of the microfilaments in maintaining unstimulated platelets in a functional form and in directing the responses of platelets to activation is discussed.