1. Ultrastructural identification of storage compartments and localization of activity-dependent secretion of neurotrophin 6 in hippocampal neurons.
- Author
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Gärtner A, Shostak Y, Hackel N, Ethell IM, and Thoenen H
- Subjects
- Amino Acid Sequence, Animals, Cell Compartmentation, Cell Membrane ultrastructure, Fixatives, Glutaral, Glycosylation, Heparan Sulfate Proteoglycans metabolism, Heparin pharmacology, Hippocampus metabolism, Immunohistochemistry, Microtubules ultrastructure, Models, Molecular, Nerve Growth Factors analysis, Nerve Growth Factors genetics, Neuronal Plasticity, Neurons drug effects, Neurons ultrastructure, PC12 Cells, Protein Precursors metabolism, Protein Processing, Post-Translational, Proto-Oncogene Proteins c-myc chemistry, Proto-Oncogene Proteins c-myc genetics, Rats, Rats, Wistar, Recombinant Fusion Proteins metabolism, Sequence Homology, Amino Acid, Subcellular Fractions chemistry, Tissue Fixation methods, Transfection, Hippocampus cytology, Nerve Growth Factors metabolism, Neurons metabolism
- Abstract
A modulatory role of neurotrophins (NTs) in activity-dependent neuronal plasticity by pre- and postsynaptic mechanisms is now well established. In this context, it is important to identify the storage compartments and to localize the precise site(s) and mechanism of NT secretion in order to deduce the spatial and temporal availability of NTs. We approached these questions at the ultrastructural level, exploiting the unique property of NT6 to bind tightly to heparan sulfate proteoglycans at the neuronal surface (R. Götz et al., 1994, Nature 372, 266-269), permitting the localization of secretion sites excluding diffusion artifacts. The myc tagging of NT6 permitted glutaraldehyde fixation and hence good preservation of the membrane structure, permitting immunogold labeling of NT6myc at the neuronal surface. NT6myc is preferentially secreted from neurites compared to neuronal cell bodies. In agreement with light-microscopic observations, the ultrastructural localization of NT6myc by postembedding procedures showed a predominant localization in ER-like membrane-confined compartments, partially associated with microtubules., (Copyright 2000 Academic Press.)
- Published
- 2000
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