Module 7: Figure regulation of paracellular permeability
Regulation of paracellular permeability by contraction of the cytoskeleton.
Under resting conditions, the endothelial cells provide a semi-permeable barrier by denying access to large molecules such as albumin. Inflammatory mediators induce contraction of the cytoskeleton that pulls on the molecules of the tight and adherens junctions to open up the permeability barrier to large molecules and inflammatory cells, such as neutrophils and monocytes. The signalling mechanism that controls contraction depends on the activation of contraction by both Ca2+ and RhoA, as illustrated in Module 7: Figure endothelial cell contraction.