Focal adhesions: paradigm for a signaling nexus

The vascular wall contains intimal endothelium and medial smooth muscle that act as contiguous tissues with tight spatial and functional coordination in response to tonic and episodic input from the bloodstream and the surrounding parenchyma. Focal adhesions are molecular bridges between the intracellular and extracellular spaces that integrate a variety of environmental stimuli and mediate 2-way crosstalk between the extracellular matrix and the cytoskeleton. Focal adhesion components are targets for biochemical and mechanical stimuli that evoke crucial developmental and injury response mechanisms including cell growth, movement, and differentiation, and tailoring of the extracellular microenvironment. Focal adhesions provide the vascular wall constituents with flexible and specific tools for exchanging cues in a complex system. The molecular mechanisms that underlie these vital communications are detailed in this review with the goal of defining future targets for vascular tissue engineering and for the therapeutic modulation of disordered vascular growth, inflammation, thrombosis, and angiogenesis.