Lis1 regulates the association of dynein and dynactin components. (A) Immunoblots showing that reduced Lis1 levels do not perturb the composition of dynein complexes immunoprecipitated from ovary extracts using anti-Dic antibodies. Anti-GFP antibodies were used as a control. Note that Lis1 is not detectably associated with dynein complexes immunoprecipitated from lis1^E415/lis1^k11702 extract, suggesting that the Lis1 concentration in these extracts is limiting for efficient binding to dynein. Although Dlic levels appeared different in WT and lis1 mutant extracts in the experiment shown, this difference did not affect Dlic incorporation into dynein complexes. (B) Immunoblots showing reduced levels of p150^Glued precipitated with GFP-Dlic (using GBP pull-downs) in lis1^E415/lis1^k11702 versus WT ovary extract (see Fig. S4 B for quantification of the reduced signal in multiple trials). (C) Immunoblots showing reduced levels of Dhc and Dic precipitated with GFP-p50^Dmn (using GBP pull-downs) in lis1^E415/lis1⁺ versus WT embryo extract (see Fig. S4 C for quantification of the reduced Dhc signal in multiple trials). Fluorescent detection was used for the Lis1 blot in this panel. The lower molecular weight species of GFP-p50^Dmn precipitated in this experiment is presumably a degradation product. (D) Approximately fourfold overexpression (OE) of Lis1 (quantification not depicted) increases the amount of Dhc, Dic, and BicD coprecipitated with GFP-p50^Dmn from ovary extract. Lis1 was overexpressed by driving UAS-lis1 in the germ line with MTD-GAL4. Note that, unlike in embryo extract (C), association of Lis1 with GFP-p50^Dmn is not readily detectable in WT ovary extract (D). This may be due to tissue-specific differences in the abundance, affinities, or stoichiometries of the proteins participating in the interaction.