A cyclic AMP protein kinase A-dependent mechanism by which rotavirus impairs the expression and enzyme activity of brush border-associated sucrase-isomaltase in differentiated intestinal Caco-2 cells.
We undertook a study of the mechanism by which rhesus monkey rotavirus (RRV) impairs the expression and enzyme activity of brush border-associated sucrase isomaltase (SI) in cultured, human, fully differentiated, intestinal Caco-2 cells. We provide evidence that the RRV-induced defects in the expression and enzyme activity of SI are not related to the previously observed, RRV-induced, Ca2+ -dependent, disassembly of the F-actin cytoskeleton. This conclusion is based on the facts that: (i) the intracellular Ca2+ blocker, BAPTA/AM, which antagonizes the RRV-induced increase in [Ca2+](i), fails to inhibit the RRV-induced decrease in SI expression and enzyme activity; and (ii) Jasplakinolide (JAS) treatment, known to stabilize actin filaments, had no effect on the RRV-induced decrease in SI expression. Results reported here demonstrate that the RRV-induced impairment in the expression and enzyme activity of brush border-associated SI results from a hitherto unknown mechanism involving PKA signalling. This conclusion is based on the observations that (i) intracellular cAMP was increased in RRV-infected cells and (ii) treatment of RRV-infected cells with PKA blockers resulted in the reappearance of apical SI expression, accompanied by the restoration of the enzyme activity at the brush border. In addition, in RRV-infected cells a twofold increase of phosphorylated form of cytokeratin 18 was observed after immunopurification and Western Blot analysis, which was antagonized by exposing the RRV-infected cells to the PKA blockers.
Martin-Latil
Sandra
S
Institut National de la Santé et de la Recherche Médicale, Unité 510, Pathogènes et Fonctions des Cellules Epithéliales Polarisées, Faculté de Pharmacie, Université Paris XI, 92296 Châtenay-Malabry, France.
Cotte-Laffitte
Jacqueline
J
Beau
Isabelle
I
Quéro
Anne-Marie
AM
Géniteau-Legendre
Monique
M
Servin
Alain L
AL
D018938:Caco-2 Cells / Q000187:drug effects / Q000378:metabolism / Q000821:virology*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D047630:Depsipeptides; D006801:Humans; D007633:Keratins / Q000378:metabolism; D010456:Peptides, Cyclic / Q000494:pharmacology; D010766:Phosphorylation; D012401:Rotavirus / Q000502:physiology*; D015398:Signal Transduction; D013394:Sucrase-Isomaltase Complex / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000378:metabolism*
D002121:Calcium Channel Blockers; D047630:Depsipeptides; D010456:Peptides, Cyclic; C057531:jasplakinolide; D007633:Keratins; D017868:Cyclic AMP-Dependent Protein Kinases; D013394:Sucrase-Isomaltase Complex