Focal Adhesions

Focal adhesions are multimolecular complexes that mediate interactions between the extracellular matrix and the cytoskeleton. In comparison to nascent adhesions and focal complexes, they are relatively large, long-lasting, and are typically found associated with actomyosin stress fibers. Extracellularly, they are comprised of clusters of membrane-spanning integrins that associate with the extracellular matrix. Inside the cell a range of scaffolding and adaptor proteins, such as Talin, Vinculin, and Paxillin, directly or indirectly bind integrins and actin filaments. Focal adhesions are important for regulating cell adhesion and motility, and they have putative roles in development, wound healing, angiogenesis, tumor cell invasion, and metastasis. Focal adhesions are more than just structural complexes. Many signaling molecules are found at these sites including Focal Adhesion Kinase (FAK) and Src. In addition to regulating cell motility, these signaling complexes also have putative roles cell proliferation, survival, and differentiation.