Fig. 2.

Ca²⁺-dependent membrane localization of TJ proteins in MLE15 cells. MLE15 cells grown in normal Ca²⁺ medium (NC) for 24–48 h (A,E,I) were Ca²⁺ starved overnight (NC to LC; B,F,J), then switched to NC medium for 2 h or 24 h (LC to NC; C,D,G,H,K,L) to induce TJ biogenesis, and then processed for immunofluorescence with specific TJ protein antibodies. Note belt-like pattern of membrane immunostaining of ZO-1, occludin and claudin1 at areas of intercellular contact in A,E,I,D,H,L (arrowheads), predominant cytosolic concentration of these proteins in B,F,J (arrows) and partial formation of TJs at areas of intercellular contact in C,G,K (arrowheads). Scale bars: 50 µm.