Fig. 7

PAK1 tyrosyl phosphorylation stimulates PRL-induced tumor metastasis in vivo. a myc-PAK1 was detected in all tumor lysates isolated from myc-PAK1 WT and myc-PAK1 Y3F inoculated mice. PRL-induced tyrosyl phosphorylation of PAK1increased tumor metastasis, as 3 out of 8 lungs from WT mice contained myc-PAK1 (lanes 2, 4 and 5). No myc-PAK1 was detected in any of the lungs from the Y3F or GFP mice. Anti-tubulin antibody was used as a loading control. Whole cell lysate (WCL) of TMX2-28 PAK1 WT cells was loaded as a control for PAK1-myc position in the gels. b–f Representative images of myc-PAK1 detected with anti-myc in breast tumor (b, c) and lung tissue (d–f). myc-PAK1 was detected in breast tumors of myc-PAK1 WT- (b) and Y3F- (c) and lung of myc-PAK1 WT- inoculated mice (d) but not in lungs of GFP (e) or PAK1 Y3F-inoculated mice (f). The arrow highlights metastatic nodule. Counterstaining with hematoxylin was omitted. Scale bar is 200 μm in (b) and 100 μm in (c–e)