Micrograph of a microtubule-tethering junction between the extensions of two PtK2 cells. Sections were taken from a rapidly fixed, epoxy resin embedded cell monolayer. They were contrasted, and visualized in a JEOL-1210 transmission electron microscope at 80 kV. For recording, a digital camera, Morada, and analysis FIVE software (Soft Image System) was used.  See Reipert. Traffic 2007;8(12):1706-1707.
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Electron microscopy of ER-cytosolic protein aggregates in M553 cells stably expressing C95A tapasin and TAP1 proteins tagged with GFP-like proteins. The protein aggregates (pseudo-colored in red) show juxtanuclear localization with enlarged tubuli of smooth ER that are surrounded by the mesh of cytosolic filaments. Despite similarity in dimensions and intracellular location, these protein aggregates are different from aggresomes, since proteins that initiated aggregate formation did not leave the ER and maintained their transmembrane ER topology (see Stepensky, Bangia, and Cresswell. Traffic 2007;8(11):1530-1542).
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A scanning electron micrograph of the insect stage of the protozoan parasite Trypanosoma brucei. This parasite is the causative agent of African sleeping sickness in humans and nagana in cattle. Assembly of the single flagellum (pseudo-coloured in blue) requires a mechanism called intraflagellar transport to carry components via the basal body of the flagellum to the growing tip. In this issue the authors describe a quality control mechanism occurring at the basal body prior to intraflagellar transport (see Stephan et al. Traffic 2007;8(10):1323-1330).
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A montage of a confocal image of a lamprey giant reticulospinal synapse.
Labeled with amphipysin antibodies (green) and phalloidin (red), and an electron micrograph of a reticulospinal synapse. For details see Evergren et al. Traffic 2004;5:514-528.
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Notch receptors are clustered and trans-endocytosed by Delta ligand cells. Confocal micrograph of a Delta expressing cell (left) interacting with a Notch expressing cell (right). Following interaction with Delta (blue), cell surface Notch (yellow) is clustered at cell-cell interfaces. Notch extracellular domain is detected within Delta cells (green) indicative of trans-endocytosis. Endocytosis of ligand while bound to Notch may produce a force sufficient to pull Notch apart and activate signaling. (See Nichols et al. Traffic 2007;8(8):959-969).
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Mouse bone marrow derived mast cell analyzed by electron microscopy after fixation and embedding in epon resin. Image courtesy of G. Raposo (see Mizuno et al. Traffic 2007; 8(7):883-892).
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Mechanism of a clathrin/dynamin independent endocytic pathway involves cholesterol dependent Cdc42 activation step. Electron micrograph (background) shows GPI-anchored proteins and small molecule Rho GTPase Cdc42 coclustered in the plane of plasma membrane. Live TIRF microscopy suggests that these regions are also rich in actin (upper right corner). These dynamic assemblies on plasma membrane are maintained by cycling on and off of single molecules of Cdc42 (centre). These actin, Cdc42 and GPI anchored protein-rich domains are proposed give rise to dynamin/clathrin independent carriers (lower left corner). (See Chadda et al. Traffic 2007; 8(6):702-717).
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In vivo GFP-labelling of Paramecium Syntaxin1-1 and Syntaxin2-1.
Left panel TOP At the cell surface, GFP-PtSyntaxin1-1 fluorescence is concentrated in puncta that are regularly arranged along the cell surface. Staining is enhanced near the fission region of dividing cells. BOTTOM Localization of Paramecium Syntaxin2-1-GFP. The fusion protein is targeted to the contractile vacuole complex (osmoregulatory system) where it localizes to the radial arms and the associated spongiome, the ampullae and the contractile vacuole. Right panel Enlargement of PtSyntaxin2-1-GFP staining in living cells showing the dynamic nature of the organelle: the contractile vacuole before (diastole; TOP) and during (systole; BOTTOM) fluid discharge.  Image courtesy of C. Schilde (see Kissmehl et al. Traffic 2007;8(5):523-542).
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Lysosomal recruitment to the bead-containing phagosomes of bone marrow derived macrophages. Macrophages were pulsed with the Alex Fluor 594-hydrazide (red) for a period of 5 hours and subsequently chased to the lysosomes overnight. Macrophages were fed mannosylated BSA-coated, 3µm silica beads labeled with Alexa Fluor 488 (green). After 2 hours, the cells were fixed with paraformaldehyde and images were taken with a Zeiss Axiovert 200M microscope equipped with a Zeiss LSM 510 META confocal system. The shadow-projected image of a 3D reconstruction was generated using the VisArt module of the Carl Zeiss AIM software. The image was generated by Craig Lassy and Ross La Rosa (Carl Zeiss Microimaging Inc) and Robin Yates and David Russell (Cornell University). (See Yates et al. Traffic 2007;8(3):241-250).
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Inhibitory and excitator synapses revealed by triple labeling on 21 DIV cortical neurons. Green: glutamatergic terminals revealed by v-glut-1; Blue and red GABAergic terminals revealed by GAD (blue) and GABA A (red). Image courtesy of M Matteoli (see Verderio et al. Traffic 2007;8(2):142-153).
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Targeting of TMV movement protein to plasmodesmata requires the actin/ER network. The image shows the leading edge of an infection site produced by a Tobacco mosaic virus vector expressing a movement protein-mRFP fusion in epidermal cells of Nicotiana benthamiana plants, expressing a fusion of GFP to Arabidopsis a-tubulin. The movement protein (magenta) targets plasmodesmata and forms clusters at the vertices of the endoplasmic reticulum. At this stage of infection, the movement protein does not show any particular association with microtubules (green). Cover image courtesy of Kathryn Wright. (See Traffic 2007; 8(1):21-31).
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