Specificity of pAb506P.

<p><b>(A)</b> Comparative titration curves of pAb506P on ELISA plates coated with a topo I peptide surrounding the serine 506 site, either in its phosphorylated or non-phosphorylated form. <b>(B)</b> Western analyses of H358 cell lysates (100 μg/lane) probed with pAb506P (lane 1) or with goat anti-topo I (lane 2). Arrows indicate positions of the 45 kDa species and full length topo I. <b>(C)</b> Topo I immunoprecipitation (goat anti-topo I C-terminus) followed by pAb506P Western of H358 cell lysates. Lane represents 200 μg starting material. <b>(D)</b>Western analysis of PS506 and actin in H358 cell lysates before (cntr) and after treatment with alkaline phosphatase (AP). <b>(E)</b> Western analysis of PS506 (using pAb506P), full length topo I (using goat anti-topo I) and tubulin in H358 cells before and after a 24 hr treatment of cells with 0.1 or 1 μM CPT.