Figure 10.

Xpo-t blockage of RanGAP stimulation of the GTPase activity of Ran is dependent on the presence of tRNA and is not alleviated by the inclusion of Scyl1. Ran-[γ-³²P]GTP (1 μM) was incubated with (•) or without (▴) 0.5 nM RanGAP. Ran also was incubated with RanGAP in the presence of 2 μM Xpo-t with (▾) or without (■) 6 μM yeast mature tRNA, or with 2 μM Xpo-t, 2 μM Scyl1, and 6 μM yeast mature tRNA (♦). At the specified times, hydrolysis of Ran-bound GTP was determined by counting released [³²P]phosphate by using the charcoal method.