Figure 1.

p18^UBC9 and p88^RanGAP1 are precipitated by anti-p340^RanBP2 antibodies. Egg extract (100 μl) was incubated with preimmune serum (lanes 1 and 2) or with anti-p340^RanBP2 serum, followed by precipitation with protein A-Sepharose beads. The beads were washed, and the bound proteins were eluted with 20 μl of SDS-sample buffer. Either 9 μl (lanes 1 and 3) or 3 μl (lanes 2 and 4) of eluted proteins was subjected to SDS/PAGE and Coomassie blue staining. The migration of molecular mass standards (in kDa) is indicated on the left. Arrows on the right indicate proteins that were specifically immunoprecipitated by the anti-p340^RanBP2 antibodies. Two peptide sequences derived from p18 are shown as Peptides A and B, with the corresponding sequences from mammalian Ubc9p indicated below each.