K129E is cytoplasmic and can inhibit apoptosis. (A) 3D ribbon model of the survivin homodimer constructed from structure 1F3H using the UCSF Chimera package (http://www.cgl.ucsf.edu/chimera). The survivin monomers are shown in light and mid-grey. Residue K129 and its side chain is highlighted in red. (B) HeLa cells in interphase stably expressing GFP, WT survivin, or K129E as indicated in green, counterstained with DAPI to highlight the nucleus (blue), bar 5 μm. Both WT and K129E localise predominantly in the cytoplasm. (C) An immunoblot showing WT and K129E are expressed at similar levels in whole cell extracts prepared from asynchronous populations. Tubulin indicates equality in loading. (D) HeLa cells expressing GFP (control), WT, or K129E were treated with TRAIL for 0–150 minutes then a caspase-3 activity performed on whole cell extracts to indicate apoptosis. Caspase activity was measured spectrophotometrically and is plotted in relative fluorescent units (RFU).