A protein kinase A-dependent mechanism by which rotavirus affects the distribution and mRNA level of the functional tight junction-associated protein, occludin, in human differentiated intestinal Caco-2 cells.

We found that at the tight junctions (TJs) of Caco-2 cell monolayers, rhesus monkey rotavirus (RRV) infection induced the disappearance of occludin. Confocal laser scanning microscopy showed the disappearance of occludin from the cell-cell boundaries without modifying the expression of the other TJ-associated proteins, ZO-1 and ZO-3. Western immunoblot analysis of RRV-infected cells showed a significant fall in the levels of the nonphosphorylated form of occludin in both Triton X-100-insoluble and Triton X-100-soluble fractions, without any change in the levels of the phosphorylated form of occludin. Quantitative reverse transcription-PCRs revealed that the level of transcription of the gene that encodes occludin was significantly reduced in RRV-infected cells. Treatment of RRV-infected cells with Rp-cyclic AMP and protein kinase A inhibitors H89 and KT5720 during the time course of the infection restored the distribution of occludin and a normal level of transcription of the gene that encodes occludin.