ABSTRACT
This chapter describes the principal molecular components of the cell cortex, and some of the specialized structures it forms. It examines that the part of the cytoskeleton is highly complicated in structural and biochemical terms and that there is still much to learn. The chapter discusses shortly in the context of focal adhesions, cell adhesions have not only a mechanical role but also a signaling one. Because of their privileged position immediately subjacent to the plasma membrane, junctional proteins relay information on the mechanical and chemical properties on the outside of the cell to its interior. The structural core of actin-rich extensions of the surface such as filopodia is a loose bundle of actin filaments. Once a filopodium or microvillus has grown out of the cell by actin polymerization, its strength and stiffness rely on proteins that hold actin filaments together.
