Figure 5.

FAK is downregulated and CRKII-DOCK180/RacGEF exhibits increased interaction with unphosphorylated Y118-Paxillin in vivo compared to in vitro. (A) Schematic of in vitro Paxillin regulation from cell culture studies. Following integrin activation, a tyrosine kinase, FAK, phosphorylates Paxillin. Phosphorylated Paxillin then recruits the adaptor protein CRKII and the Paxillin/CRKII complex further recruits DOCK180/RacGEF, thereby activating downstream Rac-dependent pathways, inducing cell migration. (B) Western blot analysis of FAK levels (FAK) and FAK activation (pY397-FAK) in YUMM1.7 cells expressing mammalian WT-Paxillin-T2A-GFP in culture and YUMM1.7 tumors in vivo. In vitro and in vivo bands are from the same blot. Unmodified Western blot is in Fig. S5 A. GFP was used as the loading control and as a control for the number of YUMM1.7 cells in mouse tumors. (C and D) Quantification of the pY397-FAK/total FAK ratio (C) and total normalized FAK to GFP expression (D) in the in vitro cell culture and in vivo conditions. n = 3 dishes, 5 tumors for C, n = 5 dishes, 8 tumors for D. Error bars are mean ± SD. Non-parametric unpaired t test. (E) Western blot analysis of pY118-Paxillin levels in YUMM1.7 cells overexpressing GFP-FAK in vitro and in vivo. Actin is used as a loading control. (F) Quantification of pY118-Paxillin/Paxillin levels in E. GFP control tumors are normalized to 1. n = 4 technical replicates. Error bars are mean ± SD. Non-parametric unpaired t test. (G–J) Co-immunoprecipitation analyses of CRKII and Paxillin in YUMM1.7 cell lines that exogenously express mammalian wildtype, Y118E and Y118F Paxillin in vitro (G and H) and in in vivo tumors (I and J). (H and J) Quantification of CRKII/Paxillin ratio from G and I, bands from cells expressing wildtype Paxillin are normalized to 1 both in vitro and in vivo. n = 3 technical replicates. Non-parametric one-way ANOVA, error bars are mean ± SD. (K) Coimmunoprecipitation analyses of DOCK180/RacGEF and Paxillin in YUMM1.7 cell lines that exogenously express mammalian wildtype, Y118E and Y118F Paxillin in vitro and in in vivo tumors. (L–N) Coimmunoprecipitation analyses of CRKII and DOCK180/RacGEF to Paxillin in YUMM1.7 cell lines that exogenously express wildtype Paxillin in in vitro and in in vivo tumors. (M) Quantification of CRKII/Paxillin levels in L. n = 4 tumors. (N) Quantification of DOCK180/Paxillin levels in L. n = 4 tumors. Error bars are mean ± SD. Non-parametric unpaired t test. Source data are available for this figure: SourceData F5.