Figure 5.

The IQ motif and N terminus are dispensable for BRAG1 catalytic activity in heterologous cells. A, Pulldown assay for Arf6 activity. Active GTP-bound Arf6 was precipitated with GST-GGA3 from lysates of HeLa cell coexpressing Arf6-HA and the indicated myc-tagged BRAG1 constructs. B, Quantitation of Arf6 activation (Ctrl: 100.0 ± 55.6%; WT: 362.0 ± 99.4%; n = 3; p < 0.05; EK: 117.3 ± 78.9%; n = 3; p = 0.5; IQ: 376.8 ± 86.0%; n = 3; p < 0.05; ΔN: 340.6 ± 131.3%; n = 3; p < 0.05). The relative values and SEs were normalized to average amounts of Arf6-GTP from control cells expressing Arf6-HA alone. **p < 0.05 (Wilcoxon test).