FIGURE 3.
Effect of Kif2A on AGAP1 activity. A, PtdIns(4,5)P2 and Kif2A cooperatively stimulate AGAP1 activity. 100 nm [193–531]Kif2A and 5 μm PtdIns(4,5)P2 were used in the GAP assay, which contained 0.5 μm myrArf1·[α32P]GTP, LUVs with PtdIns(4,5)P2 as indicated, and the indicated concentration of His-AGAP1. The reaction was followed by the conversion of [α32P]GTP to [α32P]GDP. No add'n, no addition. B, determination of the domain of Kif2A that stimulates AGAP1. The indicated His10-tagged fragments of Kif2A were titrated into reactions containing LUVs (same composition as panel A + PtdIns(4,5)P2), 1.1 nm AGAP1, and 0.5 μm myrArf1·[α32P]GTP. The reaction was followed by the conversion of [α32P]GTP to [α32P]GDP.