The Abl/enabled signaling pathway regulates Golgi architecture in Drosophila photoreceptor neurons.
Bottom Line: The Abl effector, Enabled (Ena), selectively labels the cis-Golgi in developing PRs.Finally, we demonstrate that the effects of Abl signaling on Golgi are mediated via regulation of the actin cytoskeleton.Moreover, they raise the possibility that some of the effects of Abl signaling may arise, in part, from alterations of protein trafficking and secretion.
Affiliation: Axon Guidance and Neural Connectivity Unit, Basic Neuroscience Program, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892.Show MeSH
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Mentions: We confirmed the association of Ena with the cis-Golgi by two independent approaches. First, in agreement with the foregoing observations, we found that Ena structures colocalized with GFP fusions to a cis-Golgi resident protein, α-mannosidase II (Figure 1E). Second, we used an antibody that labels the trans-Golgi compartment of the Golgi complex, anti-dSyntaxin-16 (dSyx-16), to examine the relationship between Enabled distribution and the trans-Golgi (Xu et al., 2002). In contrast to the cis-Golgi marker, we found that the trans-Golgi marker dSyx-16 labeled puncta that were adjacent to Ena structures but showed no significant overlap (Figure 1B). To further improve our resolution of Golgi structures, we used superresolution stimulated emission depletion (STED) microscopy, which offers lateral resolution of 80–100 nm, as compared with 240–450 nm for standard confocal approaches. By STED, as by traditional confocal microscopy, we observed strong colabeling of Ena with cis-Golgi structures in wild-type larval PR (Figure 1C; also see later discussion of Figure 4D). Finally, transmission immuno–electron microscopy with anti-Ena antibodies reproducibly revealed anti–Ena-gold signal associated with the cis portion of morphologically recognizable Golgi structures (Figure 1, D and D′), as well as in other regions of the cell where Ena protein is expected to be found (e.g., along the plasma membrane at the cell cortex).
Affiliation: Axon Guidance and Neural Connectivity Unit, Basic Neuroscience Program, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892.