Activation of the MAPKs ERK1/2 by cell swelling in turbot hepatocytes.

• Published in: Biology of the Cell
• Main Authors: Fouchs, Audrey, Ollivier, Hélène, Haond, Christophe, Roy, Stella, Calvès, Patrick, Pichavant-Rafini, Karine
• Other Authors: Optimisation des régulations physiologiques (ORPHY (EA 4324)), Université de Brest (UBO)-Centre Hospitalier Régional Universitaire de Brest (CHRU Brest)-Institut Brestois Santé Agro Matière (IBSAM), Université de Brest (UBO)-Université de Brest (UBO)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2010
• Subjects: MESH: Adenosine Triphosphate; MESH: Animals; MESH: Enzyme Activation; MESH: Flatfishes; MESH: Hepatocytes; MESH: Hypotonic Solutions; MESH: Mitogen-Activated Protein Kinase 1; MESH: Mitogen-Activated Protein Kinase 3; MESH: Osmotic Pressure; MESH: Phosphorylation; MESH: Receptors; Purinergic P2; MESH: Thapsigargin; MESH: Calcium; MESH: Cell Size; MESH: Egtazic Acid; [SDV.MHEP.PHY]Life Sciences [q-bio]/Human health and pathology/Tissues and Organs [q-bio.TO]; Mek; Turbot
• Online Access: https://hal.univ-brest.fr/hal-00837573; https://doi.org/10.1042/BC20090154

International audience BACKGROUND INFORMATION: Activation of MAPKs (mitogen-activated protein kinases), in particular ERK1/2 (extracellular-signal-regulated kinase 1/2), has been reported to take place in a large variety of cell types after hypo-osmotic cell swelling. Depending on cell type, ERK1/2 phosphorylation can then serve or not the RVD (regulatory volume decrease) process. The present study investigates ERK1/2 activation after aniso-osmotic stimulations in turbot hepatocytes and the potential link between phosphorylation of these proteins and RVD. RESULTS: In turbot hepatocytes, Western-blot analysis shows that a hypo-osmotic shock from 320 to 240 mOsm kg(-1) induced a rapid increase in ERK1/2 phosphorylation, whereas a hyper-osmotic shock from 320 to 400 mOsm kg(-1) induced no significant change in the phosphorylation of these proteins. The hypo-osmotic-induced ERK1/2 phosphorylation was significantly prevented when hypo-osmotic shock was performed in the presence of the specific MEK (MAPK/ERK kinase) inhibitor PD98059 (100 microM). In these conditions, the RVD process was not altered, suggesting that ERK1/2 did not participate in this process in turbot hepatocytes. Moreover, the hypo-osmotic-induced activation of ERK1/2 was significantly prevented by breakdown of extracellular ATP by apyrase (10 units ml(-1)), by inhibition of purinergic P2 receptors by suramin (100 microM) or by calcium depletion using EGTA (1 mM) and thapsigargin (1 microM). CONCLUSIONS: In turbot hepatocytes, hypo-osmotic swelling but not hyper-osmotic shrinkage induced the activation of ERK1/2. However, these proteins do not seem to be involved in the RVD process. Their hypo-osmotic-induced activation is partially due to cascades of signalling events triggered by the binding of released ATP on purinergic P2 receptors and requires the presence of calcium.