Influence of metabolic inhibitors on the degradation of tight junctions in HT29 cells.

The human colon adenocarcinoma cell line HT 29 grows in culture without tight junctions (TJ). Tight junction strands of the fascia occludens type can be induced by treatment with proteases and are subsequently degraded during a period of about 3 h. Experiments using a variety of metabolic inhibitors such as 2-deoxyglucose, 2,4-dinitrophenol, and CCCP show that the degradation of TJ is retarded under conditions of ATP depletion. Thus it appears that the removal of TJ from the cell surface is an energy-dependent process. Moreover, DNP can specifically inhibit the degradation of TJ even in the absence of ATP depletion. The possible involvement of a proton gradient in the mechanism of TJ degradation is discussed.