Figure 5

Expression and subcellular localization of endogenous Anx in MDA-MB-231. (a) 10 µg of protein extracts from MDA-MB-231 and BeWo cells were analyzed by western-blot. The gel analysis plugin of ImageJ was used to quantify the density of bands. The histogram presents mean values (± SD) of the ratio Anx/GAPDH from ten independent experiments. Student t Test for independent samples. **p < 0.01. (b) Revelation of AnxA5 in MDA-MB-231 and BeWo cells compared to 50 ng purified recombinant AnxA5 (Pure A5), presented as an example. The whole membrane, together with representative western-blot analysis for AnxA1, A2, A4 and A6, are presented in Supplementary Fig. 2. (c) MDA-MB-231 cells were immunostained for AnxA1, AnxA2, AnxA4, AnxA5 and AnxA6 (green), as indicated, and counterstained with DAPI (blue). The right-hand column presents magnified images extracted from the “Anx” column (indicated by inserts). Scale bar: 40 µm. (d) Quantification of fluorescence intensities after immunostaining of endogenous Anx in MDA-MB-231 cells. Fluorescence intensities were measured from 8-bit images by drawing a circular ROI inside the cytoplasm and measuring the mean pixel value. Mean pixel values from at least 20 cells are presented. Horizontal bars represent median values. The variance value is 323, 268, 224, 2372 and 2909 for AnxA1, A2, A4, A5 and A6, respectively. The coefficient of variation is 14%, 13%, 24%, 35% and 47% for AnxA1, A2, A4, A5 and A6, respectively. The expression level of AnxA5 or AnxA6 is heterogenous from one MDA-MB-231 cell to another. In some cells, AnxA5 and AnxA6 are expressed at a very low level.