Differential signalling of mutant PDGFRα from the ER and plasma membrane. (A) Flow cytometric analysis of PDGFRα surface expression in 293FR-PDGFRα-D842V cells treated with doxycycline for 4 h in the presence of the indicated amount of BrefeldinA (BFA). (B) 293FR-PDGFRα-D842V cells were treated as described in (A). After cell lysis, the different glycosylated forms of the receptor were visualized using antibodies recognizing pPDGFRα or PDGFRα. (C) Cells were treated as described above and the effects of Golgi-destruction on conventional PDGFRα signalling were assessed by Western blot analysis using the corresponding antibodies. (D) The effects of Golgi-destruction on unconventional PDGFRα signalling via STAT factors were assessed by Western blot analysis using the corresponding antibodies.