Fig. 3.

A model of the architecture of the AJC. Scheme showing a simplified model of the architectural organization of the AJC (bicellular junctions) and the associated actomyosin cytoskeleton. For simplicity, only a few major transmembrane proteins (occludin, claudins, JAM-A and cadherin), cytoplasmic scaffolds (ZO proteins), adaptors (cingulin) and cytoskeletal proteins (actin and myosin only, not microtubules) are shown. Occludin is representative of TAMPs, which include tricellulin at tTJs. JAM-A is representative of Ig-like CAMs, which include angulins at tTJs. Branched actin filaments associated with monomers or oligomers of myosin-2B are believed to tether the actomyosin belt to TJs, either by direct binding of actin filaments to ZO-1- and JAM-A-based complexes, and/or by cingulin-dependent tethering of myosin-2B to ZO-1. Proteins and protein complexes are not drawn to scale, and protein complexes are only shown at the section of membranes, whereas in vivo they are distributed continuously along the circumference of the AJC. This scheme was inspired by a similar scheme in Cartagena-Rivera et al. (2017), which is published under the terms of a CC-BY 4.0 license.