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. 2008 Mar 14;9(4):356–362. doi: 10.1038/embor.2008.28

Figure 2.

Figure 2

Pak1 and Pak2 are necessary for IL-2Rβ entry but not for transferrin uptake. (A) Endocytosis of IL-2Rβ (red) and Tf (blue) in cells transfected with the Pak1 inhibitory domain, myc-PID (green). Endocytosis and immunofluorescence were carried out as described in Fig 1A (asterisks indicate the cells expressing myc-PID). (B) Quantification of (A) and of Hep2β cells transfected with GFP as a control was carried out as described in Fig 1C. (C) Quantification of intracellular IL-2Rβ and Tf in Pak1- and/or Pak2-knockdown cells. Hep2β cells were transfected with small interfering RNA (siRNA) against Pak1 (siRNAPak1), Pak2 (siRNAPak2) or against an irrelevant protein (siRNAC). Endocytosis and quantification were carried out for 200 cells. The results are expressed as a percentage of the intracellular fluorescence intensity of control cells (siRNAC). (D) Western blots of siRNA-transfected cells were probed with antibodies against Pak1, Pak2 or against flotillin 2 (Flot2) as a control; quantification by Storm FluoroImager. GFP, green fluorescent protein; IL-2Rβ, interleukin-2 receptor β; Pak, p21-activated kinase; PID, Pak inhibitory domain; Rac1, Ras-related C3 botulinum toxin substrate 1; Tf, transferrin.