Figure 1.

Cys2 is critical for oxidation-sensitive proteasome degradation of RGS4 protein in MDA-MB-231 cells (A) and HEK293 cells (B). Cells were transfected with 1 μg plasmids encoding HA-tagged WT RGS4 or RGS4C2S mutant. Cells under hypoxia (+) or nomoxia (-) for 24 hrs were treated without or with 20 μM MG132 for 4 hrs. Proteins in cell lysate were subjected to western blot analysis with anti-HA and anti-β-actin antibodies. Images shown are representatives of four separate experiments.