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DMSO increases tyrosine residue phosphorylation in membranes from murine erythroleukemia cells
Abstract:
Phosphorylation of membranes from murine erythroleukemia cells was performed in the presence and absence of the polar solvent dimethyl sulfoxide. Quantitation of the phosphoamino acid content revealed that DMSO stimulated phosphotyrosine accumulation by three-fold; serine and threonine phosphorylation decreased significantly. We had previously shown that DMSO stimulated tyrosine residue phosphorylation of the hepatic epidermal growth factor receptor. EGF had little effect in MEL membranes; therefore, DMSO results in accumulation of phosphotyrosine in cell membranes that do not exhibit significant EGF-dependent phosphorylation.
Insights
Dimethyl sulfoxide (DMSO) significantly increases phosphotyrosine levels in murine erythroleukemia cell membranes. This occurs independently of epidermal growth factor signaling, suggesting a novel pathway for tyrosine phosphorylation.
Area of Science:
- Cellular biology
- Biochemistry
- Signal transduction
Background:
- Dimethyl sulfoxide (DMSO) is a known inducer of differentiation in murine erythroleukemia (MEL) cells.
- Tyrosine phosphorylation plays a critical role in cellular signaling pathways.
- Epidermal growth factor (EGF) receptor signaling is a key pathway involving tyrosine phosphorylation.
Purpose of the Study:
- To investigate the effect of DMSO on membrane phosphorylation in MEL cells.
- To determine if DMSO-induced tyrosine phosphorylation is linked to EGF receptor activity.
Main Methods:
- Phosphorylation assays were performed on membranes isolated from MEL cells.
- Quantitation of phosphoamino acid content (phosphotyrosine, phosphoserine, phosphothreonine) was conducted.
- Experiments were conducted in the presence and absence of DMSO.
Main Results:
- DMSO treatment resulted in a three-fold increase in phosphotyrosine accumulation in MEL cell membranes.
- Serine and threonine phosphorylation levels significantly decreased upon DMSO treatment.
- EGF had minimal effect on phosphorylation in MEL cell membranes, indicating DMSO's effect is independent of EGF signaling.
Conclusions:
- DMSO induces significant accumulation of phosphotyrosine in MEL cell membranes.
- The observed DMSO effect on tyrosine phosphorylation is independent of the epidermal growth factor receptor pathway.
- These findings suggest a novel mechanism of DMSO-mediated signaling in erythroleukemia cells.