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. Author manuscript; available in PMC: 2013 Feb 1.
Published in final edited form as: Semin Cell Dev Biol. 2011 Oct 21;23(1):65–74. doi: 10.1016/j.semcdb.2011.10.012

Figure 3.

Figure 3

Ephrin-B1 regulates tight junction formation through an interaction with Par-6. Unphosphorylated ephrin-B1 may compete with activated Cdc42 for binding to Par-6. Lack of a Par-6/Cdc42 interaction inhibits aPKC activation, leading to tight junction disruption (left panel). Tyrosine phosphorylation of ephrin-B1 precludes an interaction with Par-6, leaving it available to interact with Cdc42-GTP and establish tight junctions (middle panel). In the absence of ephrin-B1, Par-6 that is localized to adherens junctions and lateral cell borders may compete with tight junction localized Par-6 for active Cdc42. This may effectively reduce available Cdc42 at the apical border, resulting in a reduction of aPKC activity and disrupt tight junctions (right panel). Alternatively, an as yet unknown cell adhesion molecule that normally associates with ephrin-B1 may no longer function in the absence of ephrin-B1, resulting in loss of TJs and AJs. (Figure adapted from [24]).