Figure 4. Membrane association is necessary but not sufficient for ROS localization. Fusion proteins are associated with Golgi and post-Golgi membranes. (A–C) Confocal micrographs of a cell expressing GFP-CT44del25 labeled with TR-WGA (red) and Hoescht 33342 (blue). (A) TR-WGA labeling; (B) GFP fluorescence (green); (C) the overlap of the two images. Regions of colocalization are represented by yellow/orange. Together, these demonstrate that the fusion protein colocalizes with membranes, specifically Golgi and post-Golgi membranes (arrows), plasma membrane (arrowheads), and ROS membranes. (D–F) Confocal micrographs of transgenic retinas expressing GFP-CT25 (D), mGFP (E), and mGFP-CT44 (F). Nuclei were stained with Hoechst 33342 dye. GFP-CT25 did not associate with membranes and was not efficiently transported to the ROS. mGFP was membrane associated and was found in both ROS and RIS membranes including mitochondrial membranes found immediately below the inner/outer segment junction (arrows). mGFP-CT44 distributed almost exclusively to the ROS. Together, these demonstrate that both membrane attachment and a targeting signal are required for restricted ROS localization. GFP (green) and Hoescht 33342 (blue). os, outer segment; is, inner segment; n, nucleus; m, mitochondria, and s, synaptic terminal. Bars: (A–C) 2.5 μm; (D–F) 5 μm.
Image published in: Tam BM et al. (2000)
© 2000 The Rockefeller University Press. This image is reproduced with permission of the journal and the copyright holder. This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike license
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