Figure 1

Expression of Gαi1 in the taxol-sensitive and -resistant cells. Whole cell lysate was prepared from each of the cell line by scraping into a buffer containing 20 mM Tris-HCl, pH 7.5, 150 mM NaCl, 1 mM EDTA, 1 mM EGTA, 1% (v/v) Triton-X-100, 0.5% (v/v) Nonidet P40, 2.5 mM Na pyrophosphate, 1 mM NaOV, 50 mM NaF and 1× protease inhibitor cocktail and incubated on ice for 15 minutes. The lysate was then centrifuged at 13,000 × g for 20 min and the supernatant was transferred to a fresh tube and stored at -80°C until use. Proteins (25 μg/lane) were separated on a SDS-PAG and transferred to a PVDF membrane. Western blotting analysis was performed using rabbit polyclonal antibody against Gαi1 and enhanced chemiluminescence reagents. Expression of α-tubulin was evaluated in the same lysates to ensure equal protein concentrations in each sample. For Northern blotting analysis, total RNA (20 μg) extracted from each cell was separated and transferred to Nylon membrane. Full-length Gαi1 cDNA was used as probe. The ethidium bromide stained RNA gel is shown in the bottom right-hand corner to ensure equal RNA loading.