Fig. 2.

Tao-1 colocalises with microtubules. Drosophila S2R⁺ cells were fixed and stained with microtubules (MT) as well as for polyclonal antibodies raised against Tao-1 (Tao) and phosphorylated Tao-1 (P-Tao), and examined by confocal microscopy. (A,B) Tao-1 is partially colocalised with microtubules, whereas the phosphorylated population manifests a more diffuse staining, though is enriched at the tips of a number of bundles. Scale bars: 5 μm. The specificity of the antibodies was confirmed by (C) disappearance of endogenous Tao-1 and phosphorylated Tao-1 signal (arrows) on dsRNA knockdown compared with a control protein (Sra1) on western blot, and (D) by the appearance of the appropriate signal upon overexpression of GFP-tagged Tao-1. The epitope for anti-phosphorylated Tao-1 was confirmed to be phospho-specific by lambda protein phosphatase treatment of lysates of overexpressed GFP-Tao-1 (D, upper panel). A GFP-tagged mutant of Tao-1 lacking the central domain (GFP-Δ423-900), which is a dominantly active form, was also phosphorylated.