Fig. 2. DP protein localization was characterized in HMEC-1 and C166 cells. (A-C) HMEC-1 cells grow as monolayers in tissue culture dishes; however, 5 hours after plating onto matrigel they form microvascular tubes (B,C). Inset in C is a toludine blue, semithin section of a microvascular tube grown on matrigel in culture. The lumen (arrows) in these tubes is usually found embedded in the matrigel. In monolayers VE-Cad is localized to cell membranes (D; arrow), while DP (E) appears to be cytoplasmic. (F,G) Once plated onto matrigel, VE-Cad (F) and DP (G) colocalize with one another (H). I and J show morphologically and immunohistochemically the localization pattern of VE-Cad (I; arrowheads) and DP (J; arrows) in microvascular tubes. (K) DP also is localized to cell-cell contacts in C166 microvascular tubes. Note: the microvascular tube shown in F-H is morphologically similar to those found in I-K. Bars, 100 µm (A,B); 50 µm (C and inset); 25 µm (D,E), 20 µm (F-H); 40 µm (I-K).