Fig. 4.

The proportion of carbonylated GFAP, β-actin and β-tubulin in LPS-stimulated astrocytes increases upon incubation with the proteasome inhibitor epoxomicin. LPS-treated astrocytes were incubated in the absence or presence of epoxomicin. After 24 hours, carbonylated proteins were converted into biotinylated proteins and were isolated using streptavidin-agarose as described in “Materials and Methods”. Aliquots of the starting material (total) and the streptavidin-purified fraction (bound) were separated on SDS-gels and transferred to PVDF membranes. Blots were probed with antibodies against β-actin, β-tubulin and GFAP, and were developed by ECL (panel A). Densitometric scans were obtained to calculate the proportion of the various carbonylated species in epoxomicin-treated and untreated activated astrocytes (Panel B). Values represent the mean ± SEM of 3 experiments. *p<0.05, **p<0.01.