Fig. 6. Probing the avidity of L-plastin phosphorylation variants for cellular actin structures by detergent extraction. (A) Immunolocalisation of L-plastin variants after detergent extraction. Transfected Vero cells expressing L-plastin wild-type (upper panels), Ser5Ala (middle panels) or Ser5Glu (lower panels) were extracted with Triton X-100 prior to fixation. Cells were stained with anti-sv-tag antibody (right row) and Rhodamine-phalloidin (left row) as described in Fig. 3A. Bars, 15 µm. (B) Quantification of extraction experiments. Cells exhibiting a sv-positive staining pattern were counted on untreated (no extraction) and detergent-extracted (extraction) coverslips, as described in Materials and Methods. (C) Immunolocalisation of phosphorylated wild-type L-plastin after detergent extraction. Transfected Vero cells expressing wild-type L-plastin were extracted as described in A and stained with Rhodamine-phalloidin (left panel) and anti-Ser5-P antibody (middle panel). Right panel shows a merge of enlarged regions (boxes) of left and middle images. Green, Ser5-P WT L-plastin; red, F-actin. Bar, 15 µm.