Figure 5.

Stimulation of nucleotide exchange on wild-type and E1-Ran in the presence of RCC1. (A) Recombinant wild-type Ran·[α-³²P]GTP (∼1 μM, ○, •) or E1-Ran·[α-³²P]GTP (∼1 μM, □, ▪) proteins were incubated in the presence (•, ▪) or absence (○, □) of 0.2 μM RCC1. All reactions contained 1 mM unlabeled GDP. At the indicated times, the percentage of ³²P still bound to Ran was determined (see MATERIALS AND METHODS). (B) Recombinant wild-type Ran·[β-³⁵S]GDP (∼1 μM, ○, •) or E1-Ran·[β³⁵S]GDP (∼1 μM, □, ▪) proteins were incubated in the presence (•, ▪) or absence (○, □) of 0.2 μM RCC1. All reactions contained 1 mM unlabeled GTP. At the indicated times, the percentage of ³⁵S still bound to Ran was determined.