Dual modes of endoplasmic reticulum-to-Golgi transport in dendrites revealed by live-cell imaging.
Organelles of the neuronal secretory pathway are critical for the addition of membrane that accompanies neuronal development, as well as for the proper localization of plasma membrane proteins necessary for polarity, synaptic transmission, and plasticity. Here, we demonstrate that two organizations of the secretory pathway exist in neurons: one requiring processing of membrane and lipids in the Golgi complex of the cell body and one in which endoplasmic reticulum (ER)-to-Golgi trafficking is localized to dendrites. Using time-lapse imaging of green fluorescent protein-tagged cargo proteins and compartment markers, we show that organelles of the secretory pathway, including ER, ER exit sites, and Golgi, are present and engage in trafficking in neuronal dendrites. We find that ER-to-Golgi trafficking involves highly mobile vesicular carriers that traffic in both the anterograde and retrograde directions throughout the dendritic arbor. Dendritic Golgi outposts, which appear developmentally during the phase of process outgrowth, are involved in the trafficking of both integral membrane proteins and the secreted neuronal growth factor BDNF. This distributed dendritic Golgi represents an organization of the secretory pathway unique among mammalian cells.
Horton
April C
AC
Department of Neurobiology, Duke University Medical Center, Durham, North Carolina 27710, USA.
Ehlers
Michael D
MD
D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics / Q000378:metabolism; D002451:Cell Compartmentation / Q000502:physiology; D002478:Cells, Cultured; D003712:Dendrites / Q000502:physiology* / Q000648:ultrastructure; D004721:Endoplasmic Reticulum / Q000502:physiology* / Q000648:ultrastructure; D006056:Golgi Apparatus / Q000502:physiology* / Q000648:ultrastructure; D049452:Green Fluorescent Proteins; D006624:Hippocampus / Q000166:cytology / Q000196:embryology; D007150:Immunohistochemistry; D020407:Internet; D008164:Luminescent Proteins / Q000235:genetics; D008562:Membrane Glycoproteins / Q000235:genetics; D018613:Microscopy, Confocal; D009474:Neurons / Q000502:physiology / Q000648:ultrastructure; D011499:Protein Processing, Post-Translational / Q000502:physiology; D021381:Protein Transport / Q000502:physiology; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D013696:Temperature; D014741:Video Recording; D014759:Viral Envelope Proteins / Q000235:genetics
D019208:Brain-Derived Neurotrophic Factor; C028391:G protein, vesicular stomatitis virus; D008164:Luminescent Proteins; D008562:Membrane Glycoproteins; D011993:Recombinant Fusion Proteins; D014759:Viral Envelope Proteins; D049452:Green Fluorescent Proteins