Figure 6

Mesotrypsin plays a supportive role in forming adherens junctions (AJs) and tight junctions (TJs). (A) The experimental timeline for the analysis of TJ formation is depicted at the top. Immunolocalization of E-cadherin (green) and ZO-1 (red) in HaCaT cells expressing Venus only (left) or Venus-mesotrypsin (right). In the middle, HaCaT cells without transgene expression were generated. The cells were counterstained with Hoechst 33258. Scale bars, 50 µm. (B) Quantification of the accumulation of E-cadherin (left) and ZO-1 (right) in HaCaT cells expressing Venus-mesotrypsin. The signal intensities of E-cadherin (left) and ZO-1 (right) per unit length of the cell-edge lines were measured. n = 3, **p < 0.01. Randomly selected 30 (left) or 29 cells (right) were analyzed in each experiment. The presence of Venus-mesotrypsin significantly accelerates the accumulation of E-cadherin and ZO-1 at cell–cell contact sites. Treatment with only the JNK inhibitor was insufficient for promoting TJ formation in HaCaT cells expressing Venus alone or lacking Venus-mesotrypsin.