Osmosignalling in C6 glioma cells

FEBS Letters

Häussinger, Dieter¹  Sinning, Ralf¹  Kubitz, Ralf¹  Schliess, Freimut¹ 

[1] Medizinische Einrichtungen der Heinrich-Heine Universität, Klinik für Gastroenterologie und Infektiologie, Moorenstrasse 5, D-40225 Düsseldorf, Germany

关键词: C6 glioma cell;    Signal transduction;    Calcium;    MAP kinase;    Protein kinase C;    Phospholipase C;    cAMP;    Raf-1;    Cell volume;    Erk;    extracellular signal-regulated kinase;    IP3;    inositol-(1;    4;    5)-trisphosphate;    MAP;    mitogen-activated protein or microtubule-associated protein;    MBP;    myelin basic protein;    PI3 kinase;    phosphatidylinositol-3 kinase;    PKA;    protein kinase A;    PKC;    protein kinase C;    PLC;    phospholipase C;    RVD;    regulatory volume decrease;    RVI;    regulatory volume increase;   

DOI  :  10.1016/S0014-5793(96)01376-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The influence of aniso-osmolarity on the activity of the MAP kinases Erk-1 and Erk-2 was studied in C6 glioma cells. Hypo-osmotic treatment (205 mosmol/l) led to an increased activity of Erk-1 and Erk-2 within 3 min, which became maximal at 10 min and returned to basal level within 120 min. In contrast, Erk activity was reduced under hyper-osmotic conditions (405 mosmol/l), compared to the normo-osmotic control (305 mosmol/l). Erk activation was accompanied by a mobility shift of Raf-1. Hypo-osmotic exposure increased the cytosolic Ca²⁺ concentration ([Ca²⁺]_i). Absence of extracellular Ca²⁺ largely abolished the [Ca²⁺]_i response to hypo-osmolarity, whereas Erk activation following hypo-osmotic stimulation remained unaffected, suggesting a Ca²⁺ independence of the osmosignalling pathway to the MAP kinases. Both the Ca²⁺ response as well as the Erk activation following hypo-osmotic exposure were maintained in the presence of the phospholipase C inhibitor U73122. Application of 8-CPT cAMP, forskolin/isobutylmethylxanthine or isoproterenol blocked Erk activation following hypo-osmotic treatment of the cells, suggesting a role of the Ras/Raf pathway upstream from Erk-1 and Erk-2. Protein kinase C (PKC) is unlikely to play a role in the hypo-osmolarity- induced signalling towards MAP kinases, as revealed by inhibition of PKC with Gö6850. Inhibition of pertussis- or cholera toxin-sensitive G-proteins as well as inhibition of tyrosine kinases with genistein and of PI3 kinase by wortmannin had no effect on the Erk response to hypo-osmolarity. It is concluded that osmosignalling in C6 glioma cells differs upstream of the MAP kinases from that observed in primary rat astrocytes, H4IIE rat hepatoma cells and isolated rat hepatocytes.

【 授权许可】

Unknown