Fig. 5. IMP1 binds to microtubules. (A) ³²P-labelled recombinant IMP1-HMK was precipitated with tubulin and microtubule-associated proteins (MAPs) in the presence of paclitaxel and GTP. IMP1-HMK in the presence of buffer (lane 1); polymerised tubulin (lane 2); polymerised tubulin and 1.25 µg total MAPs (lane 3); polymerised tubulin and 2.5 µg total MAPs (lane 4); polymerised tubulin and 5 µg total MAPs and 15 nM leader 3 segment C RNA (lane 5); unpolymerised tubulin and 2.5 µg total MAPs (lane 6); polymerised tubulin and 2.5 µg total MAPs and 2 units RNase T1 (lane 7); polymerised tubulin and 3 µg MAP2 (lane 8). The autoradiograph is on the left, and the Coomassie brilliant blue staining is on the right. M is a molecular mass marker. (B) Pull-down of ³²P-labelled IMP1-HMK in the absence of polymerised actin (lane 1, supernatant; lane 2, pellet) or in the presence of polymerised actin (lane 3, supernatant; lane 4, pellet). Pull-down of actinin by polymerised actin (lane 5, supernatant; lane 6, pellet). The autoradiograph is on the left, and the Coomassie brilliant blue-staining is on the right.