Rapid massive assembly of tight junction strands.

Incubation at 37 degrees C of excised rat prostate tissue results in massive proliferative assembly of new tight junction strands along the entire lengths of the lateral plasma membranes of the columnar epithelial cells. The new tight junction elements are assembled within 5 minutes and have an average length six times that of those present in the apical tight junction band. Massive assembly occurs in the presence of protein synthesis inhibitors (cycloheximide) or of metabolic uncouplers (dinitrophenol). Thus, proliferative assembly of tight junction strands involves molecular reorganization from a pool of preexisting, probably membrane-associated, components. The fascia occludens and some examples of experimentally induced tight junction proliferation may reflect the massive emergence of tight junction strands when tissue is subjected to diverse stressful conditions.