scholarly journals Osmotic Regulation of MG-132-induced MAP-kinase Phosphatase MKP-1 Expression in H4IIE Rat Hepatoma Cells

2005 ◽  
Vol 16 (4-6) ◽  
pp. 193-206 ◽  
Author(s):  
Mohammad Lornejad-Schäfer ◽  
Christine Schäfer ◽  
Lisa Richter ◽  
Tilman Grune ◽  
Dieter Häussinger ◽  
...  
Keyword(s):  
Map Kinase ◽  
Hepatoma Cells ◽  
Osmotic Regulation ◽  
Map Kinase Phosphatase ◽  
Rat Hepatoma ◽  
Rat Hepatoma Cells

Osmotic Regulation of MAP-Kinase Activities and Gene Expression in H4IIE Rat Hepatoma Cells

1998 ◽  
Vol 379 (6) ◽  
pp. 667-672 ◽  
Author(s):  
Sabine Wiese ◽  
Freimut Schliess ◽  
Dieter Häussinger
Keyword(s):  
Gene Expression ◽  
Map Kinase ◽  
Hepatoma Cells ◽  
Osmotic Regulation ◽  
Rat Hepatoma ◽  
Rat Hepatoma Cells

Osmotic regulation of betaine homocysteine-S-methyltransferase expression in H4IIE rat hepatoma cells

2007 ◽  
Vol 292 (4) ◽  
pp. G1089-G1098 ◽  
Author(s):  
Christine Schäfer ◽  
Lars Hoffmann ◽  
Katrin Heldt ◽  
Mohammad Reza Lornejad-Schäfer ◽  
Gernot Brauers ◽  
...  
Keyword(s):  
Gene Expression ◽  
Mrna Expression ◽  
Tyrosine Kinases ◽  
Hepatoma Cells ◽  
Pcr Analysis ◽  
Osmotic Regulation ◽  
A Cell ◽  
Gene Expression Studies ◽  
Rat Hepatoma ◽  
Rat Hepatoma Cells

Cell hydration changes critically affect liver metabolism and gene expression. In the course of gene expression studies using nylon cDNA-arrays we found that hyperosmolarity (405 mosmol/l) suppressed the betaine-homocysteine methyltransferase ( Bhmt) mRNA expression in H4IIE rat hepatoma cells. This was confirmed by Northern blot and real-time quantitative RT-PCR analysis, which in addition unraveled a pronounced induction of Bhmt mRNA expression by hypoosmotic (205 mosmol/l) swelling. Osmotic regulation of Bhmt mRNA expression was largely paralleled at the levels of Bhmt protein and enzymatic activity. Like hyperosmotic NaCl, hyperosmotic raffinose but not hyperosmotic urea suppressed Bhmt mRNA expression, suggesting that cell shrinkage rather than increased ionic strength or hyperosmolarity per se is the trigger. Hypoosmolarity increased the expression of a reporter gene driven by the entire human BHMT promoter, whereas destabilization of BHMT mRNA was observed under hyperosmotic conditions. Osmosensitivity of Bhmt mRNA expression was impaired by inhibitors of tyrosine kinases and cyclic nucleotide-dependent kinases. The osmotic regulation of BHMT may be part of a cell volume-regulatory response and additionally lead to metabolic alterations that depend on the availability of betaine-derived methyl groups.

Osmotic regulation of STAT3 stability in H4IIE rat hepatoma cells

FEBS Letters ◽  
2005 ◽  
Vol 579 (25) ◽  
pp. 5791-5797 ◽  
Author(s):  
Mohammad Reza Lornejad-Schäfer ◽  
Ute Albrecht ◽  
Diana Poppek ◽  
Thor Gehrmann ◽  
Tilman Grune ◽  
...  
Keyword(s):  
Hepatoma Cells ◽  
Osmotic Regulation ◽  
Rat Hepatoma ◽  
Rat Hepatoma Cells

scholarly journals Osmotic regulation of insulin-induced mitogen-activated protein kinase phosphatase (MKP-1) expression in H4IIE rat hepatoma cells

2003 ◽  
Vol 371 (2) ◽  
pp. 609-619 ◽  
Author(s):  
Mohammad Reza LORNEJAD-SCHÄFER ◽  
Christine SCHÄFER ◽  
Dirk GRAF ◽  
Dieter HÄUSSINGER ◽  
Freimut SCHLIESS
Keyword(s):  
Insulin Resistance ◽  
Protein Kinase ◽  
Map Kinase ◽  
Hepatoma Cells ◽  
Kinase Activation ◽  
P70s6 Kinase ◽  
Mitogen Activated Protein ◽  
Pkc Ζ ◽  
Rat Hepatoma ◽  
Rat Hepatoma Cells

A contribution of intracellular dehydration to insulin resistance has been established in human subjects and in different experimental systems. Here the effect of hyperosmolarity (405mosmol/l) on insulin-induced mitogen-activated protein (MAP) kinase phosphatase (MKP)-1 expression was studied in H4IIE rat hepatoma cells. Insulin induces robust MKP-1 expression which correlates with a vanadate-sensitive decay of extracellular-signal-regulated kinase (Erk-1/Erk-2) activity. Hyperosmolarity delays MKP-1 accumulation by insulin and this corresponds to impaired MKP-1 synthesis, whereas MKP-1 degradation remains unaffected by hyperosmolarity. Rapamycin, which inhibits signalling downstream from the mammalian target of rapamycin (mTOR) and a peptide inhibiting protein kinase C (PKC) ζ/λ abolish insulin-induced MKP-1 protein but not mRNA expression, suggesting the involvement of the p70 ribosomal S6 protein kinase (p70S6-kinase) and/or the eukaryotic initiation factor 4E-binding proteins (4E-BPs) as well as atypical PKCs in MKP-1 translation. Hyperosmolarity induces sustained suppression of p70S6-kinase and 4E-BP1 hyperphosphorylation by insulin, whereas insulin-induced tyrosine phosphorylation of the insulin receptor (IR) β subunit and the IR substrates IRS1 and IRS2, recruitment of the phosphoinositide 3-kinase (PI 3-kinase) regulatory subunit p85 to the receptor substrates as well as PI 3-kinase activation, and Ser-473 phosphorylation of protein kinase B and Thr-410/403 phosphorylation of PKC ζ/λ are largely unaffected under hyperosmotic conditions. The hyperosmotic impairment of both, MKP-1 expression and p70S6-kinase hyperphosphorylation by insulin is insensitive to K2CrO4, calyculin A and vanadate, and inhibition of the Erk-1/Erk-2 and p38 pathways. The suppression of MKP-1 may further contribute to insulin resistance under dehydrating conditions by allowing unbalanced MAP kinase activation.

Osmotic regulation of the heat shock response in H4IIE rat hepatoma cells

1999 ◽  
Vol 13 (12) ◽  
pp. 1557-1564 ◽  
Author(s):  
Freimut Schliess ◽  
Sabine Wiese ◽  
Dieter Häussinger
Keyword(s):  
Heat Shock ◽  
Heat Shock Response ◽  
Hepatoma Cells ◽  
Osmotic Regulation ◽  
Shock Response ◽  
Rat Hepatoma ◽  
Rat Hepatoma Cells

scholarly journals Identification of the insulin receptor tyrosine residues undergoing insulin-stimulated phosphorylation in intact rat hepatoma cells.

1988 ◽  
Vol 263 (1) ◽  
pp. 350-359 ◽  
Author(s):  
H E Tornqvist ◽  
J R Gunsalus ◽  
R A Nemenoff ◽  
A R Frackelton ◽  
M W Pierce ◽  
...  
Keyword(s):  
Insulin Receptor ◽  
Hepatoma Cells ◽  
Tyrosine Residues ◽  
Rat Hepatoma ◽  
Rat Hepatoma Cells
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