title: Hyperosmotic stress stimulates inositol 1,4,5-trisphosphate and inositol 1,3,4,5-tetrakisphosphate formation independently of bis-diphosphoinositol tetrakisphosphate modulation.
abstract: Hyperosmotic stress induces water diffusion out of the cell, resulting in cell shrinkage, and leading to DNA damage, cell cycle arrest, and cytoskeletal reorganization. A previous report showed that low concentrations of sorbitol (200mM) could increase up to 25-fold the concentration of InsP(8) in animal cells. Here, we investigate the effect of sorbitol (200mM) on the inositol 1,4,5-trisphosphate (InsP(3)) and inositol 1,3,4,5-tetrakisphosphate (InsP(4)) pathway. A 3- to 4-fold increase in InsP(3) and InsP(4) levels after sorbitol challenge was observed. It was prevented by the phospholipase C inhibitor U-73122 but was insensitive to the MAP kinase inhibitor U0126. We also observed an increase in the free intracellular [Ca(2+)] and the occurrence of Ca(2+) oscillations in response to sorbitol. A hyperosmotic stress could therefore affect the levels of both hyperphosphorylated inositol phosphates and InsP(3)/InsP(4)-signalling molecules.
authors.affiliation: Interdisciplinary Research Institute (IRIBHM), Université Libre de Bruxelles, Campus Erasme, 808 Route de Lennik, 1070 Bruxelles, Belgium. xpesesse@ulb.ac.be
authors.forename: Xavier
authors.initials: X
authors.lastname: Pesesse
authors.forename: Alexandre
authors.initials: A
authors.lastname: Leyman
authors.forename: Tomas
authors.initials: T
authors.lastname: Luyten
authors.forename: Ludwig
authors.initials: L
authors.lastname: Missiaen
authors.forename: Christophe
authors.initials: C
authors.lastname: Erneux
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D015544:Inositol 1,4,5-Trisphosphate / Q000096:biosynthesis*; D007295:Inositol Phosphates / Q000096:biosynthesis*; D007700:Kinetics; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009994:Osmolar Concentration; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D013012:Sorbitol / Q000378:metabolism
chemical_list: D007295:Inositol Phosphates; C081655:inositol-1,3,4,5-tetrakisphosphate; D013012:Sorbitol; D015544:Inositol 1,4,5-Trisphosphate; D020928:Mitogen-Activated Protein Kinases; D010749:Phosphoprotein Phosphatases; D002118:Calcium