Activation of extracellular signal-regulated kinase ERK after hypo-osmotic stress in renal epithelial A6 cells.
Activation of mitogen-activated protein (MAP) kinases has been reported to occur after a hypo-osmotic cell swelling in various types of cells. In renal epithelial A6 cells, the hypo-osmotic shock induced a rapid increase in the phosphorylation of an extracellular signal-regulated kinase (ERK)-like protein that was maximal 10 min after osmotic stress. Activation of ERK was significantly increased when hypo-osmotic stress was performed in the absence of extracellular Ca2+, a condition that inhibits regulatory volume decrease (RVD). Exposure of cells to PD98059, an inhibitor of the MAP kinase kinase MEK, at a concentration that fully cancelled ERK activation, did not inhibit RVD. On the contrary, RVD was abolished when osmotic shock was induced in the presence of SB203580, an inhibitor of stress-activated protein kinases (SAPKs). These results suggest that different MAP kinases are activated after hypo-osmotic stress in A6 cells. SAPKs would be involved in the control of RVD, while ERK would lead to later events, such as gene expression or energy metabolism.
Chiri
Sandrine
S
UMR 7622 CNRS Biologie du développement, Université Paris 6, 9 Quai St Bernard, Bat C, case 24, 75252 Paris Cedex 05, France.
Bogliolo
Stéphanie
S
Ehrenfeld
Jordi
J
Ciapa
Brigitte
B
D000818:Animals; D002118:Calcium / Q000502:physiology; D048429:Cell Size; D002478:Cells, Cultured; D004789:Enzyme Activation; D004847:Epithelial Cells / Q000166:cytology; D007668:Kidney / Q000166:cytology* / Q000201:enzymology; D020928:Mitogen-Activated Protein Kinases / Q000502:physiology*; D009997:Osmotic Pressure; D010766:Phosphorylation
D020928:Mitogen-Activated Protein Kinases; D002118:Calcium