Prolonged exposure of Swiss 3T3 cells to PMT causes the loss of Gα_i but not G_q from cell membranes.

<p>(<b>A</b>) Membrane proteins from Swiss 3T3 cells left untreated (lane 1) or treated with PMT at 1 nM for 16 h (lane 2) were separated by SDS PAGE and Western blotted with anti-Gα_q/11 antibody. Membrane proteins from Swiss 3T3 cells (<b>B</b>) left untreated, or treated with 1 nM PMT for (<b>C</b>) 4 h or (<b>D</b>) 16 h were separated by 2-D gel electrophoresis and Western blotted with anti-Gα_q/11 antibody. Samples from at least 3 independent experiments were resolved with similar results. Membrane proteins from Swiss 3T3 cells left untreated (lane 1) or treated with 1 nM PMT for 16 h (lane 2) were separated by SDS PAGE and Western blotted with (<b>E</b>) anti-Gα_i-1-3 antibody or (<b>F</b>) an antibody recognising an internal epitope of Gα_i-2. (<b>G</b>) Cytoplasmic proteins from Swiss 3T3 cells left untreated (lane 1) or treated with 1 nM PMT for 16 h (lane 2) were separated by SDS PAGE and Western blotted with anti-Gα_i-1-3 antibody. Membrane proteins from Swiss 3T3 cells (<b>H</b>) left untreated, treated with 1 nM PMT for (<b>I</b>) 4 h or (<b>J</b>) 16 h were separated by 2-D PAGE and Western blotted with anti-Gα_i-1-3 antibody. Samples from 3 independent experiments were resolved with similar results.