Actin-membrane interaction in focal adhesions.
Focal adhesions are regions of the plasma membrane where cells in tissue culture adhere strongly to the underlying extracellular matrix, and which at their cytoplasmic face serve to anchor bundles of actin microfilaments. They provide an experimental model for studying the links between the cytoskeleton and the extracellular matrix. Members of the integrin family of extracellular matrix receptors are prominent components, spanning the membrane in focal adhesions, but there is evidence that other membrane components are also needed for these structures to form. A number of proteins are concentrated at the cytoplasmic face of focal adhesions. Recent efforts have sought to determine the links between actin and the integrin cytoplasmic domains. Using in vitro binding assays, two potential bridges between actin and integrin have been identified. One involves talin, which has recently been shown to bind actin directly. The other involves the actin-binding protein, alpha-actinin, which has been found to interact with several integrins. The physiological significance of these two potential bridges between actin and integrin remains to be determined in vivo.
Burridge
K
K
Department of Cell Biology and Anatomy, University of North Carolina, Chapel Hill 27599-7090.
Nuckolls
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G
Otey
C
C
Pavalko
F
F
Simon
K
K
Turner
C
C
D000185:Actinin / Q000502:physiology*; D000199:Actins / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D002448:Cell Adhesion; D002462:Cell Membrane / Q000502:physiology*; D003598:Cytoskeletal Proteins / Q000502:physiology*; D003599:Cytoskeleton / Q000502:physiology; D005109:Extracellular Matrix / Q000378:metabolism; D016326:Extracellular Matrix Proteins / Q000502:physiology*; D016023:Integrins / Q000378:metabolism / Q000502:physiology*; D008954:Models, Biological; D011485:Protein Binding; D016608:Talin
D000199:Actins; D003598:Cytoskeletal Proteins; D016326:Extracellular Matrix Proteins; D016023:Integrins; D016608:Talin; D000185:Actinin