Figure 1.

Depletion of IAPs leads to up-regulation of Cdc42 (a) BT474, HeLa, NCI-H226 and MDA-MB231 cells were transfected with Control or XIAP siRNA for 48 h and lysates were then collected for immunoblotting. The levels of total Cdc42 were monitored in the immunoblots. Quantification was performed by densitometry (as described in Materials and Methods). (b) HeLa cells were transfected with three different XIAP siRNAs and Cdc42 levels were monitored. Further, HeLa cells transfected with the 3’-UTR XIAP siRNA were complemented with the XIAP-Flag vector and Cdc42 levels were observed. (c) Quantification of three independent experiments where three different XIAP siRNAs were used and Cdc42 protein expression was checked 48 h post transfection (d) Mouse embryonic fibroblasts (MEFs) were cultured and lysed to check for Cdc42 levels. Control MEFs and XIAP knockout MEFs stably complemented with Flag tagged XIAP were employed. (e, f) Cycloheximide chases were performed in HeLa (e) and MDA-MB231 (f), and the stabilization of Cdc42 upon depletion of XIAP was observed. (g) qPCR performed with the three different XIAP siRNAs to observe the transcriptional regulation of Cdc42. Data shown are from three independent experiments