1. the detergent stability shown by the strands suggested instead a main proteic nature Relationship between the Freeze-Fracture Appearance of TJs and TER in Cells Subjected to Different Experimental Procedures That Modify the TJ (P and E indicate the membrane fracture face) of TJ filaments (Stevenson and Goodenough, 1984). Furthermore, when the total composition of phospholipids, sphingolipids, cholesterol, and the content of fatty acids was experimentally changed in MDCK cells, no significant alteration in TER or the structure of the TJ strands was detected (Schneeberger et al., 1988; Calderón et al., 1998). Recently phospholipids derivatives have been successfully employed to enhance the paracellular absorption of drugs across epithelia (Dong-Zhou et al., 1999a,b). However, rather than acting upon the strands, these phospholipids seem to alter the intracellular mechanisms that regulate the junctional complex. Conventional freeze fracture provided crucial knowledge on the appearance of
2. Induction of Epithelial Tight Junctions by a Light Chain Protein Isolated from a Patient with Fanconi’s Syndrome