title: A functional equivalent of endoplasmic reticulum and Golgi in axons for secretion of locally synthesized proteins.
abstract: Subcellular localization of protein synthesis provides a means to regulate the protein composition in far reaches of a cell. This localized protein synthesis gives neuronal processes autonomy to rapidly respond to extracellular stimuli. Locally synthesized axonal proteins enable neurons to respond to guidance cues and can help to initiate regeneration after injury. Most studies of axonal mRNA translation have concentrated on cytoplasmic proteins. While ultrastructural studies suggest that axons do not have rough endoplasmic reticulum or Golgi apparatus, mRNAs for transmembrane and secreted proteins localize to axons. Here, we show that growing axons with protein synthetic activity contain ER and Golgi components needed for classical protein synthesis and secretion. Isolated axons have the capacity to traffic locally synthesized proteins into secretory pathways and inhibition of Golgi function attenuates translation-dependent axonal growth responses. Finally, the capacity for secreting locally synthesized proteins in axons appears to be increased by injury.
authors.affiliation: Nemours Biomedical Research, Alfred I duPont Hospital for Children, 1600 Rockland Road, Wilmington, DE 19803, USA.
authors.forename: Tanuja T
authors.initials: TT
authors.lastname: Merianda
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Lin
authors.forename: Joyce S Y
authors.initials: JS
authors.lastname: Lam
authors.forename: Deepika
authors.initials: D
authors.lastname: Vuppalanchi
authors.forename: Dianna E
authors.initials: DE
authors.lastname: Willis
authors.forename: Norman
authors.initials: N
authors.lastname: Karin
authors.forename: Christine E
authors.initials: CE
authors.lastname: Holt
authors.forename: Jeffery L
authors.initials: JL
authors.lastname: Twiss
mesh_terms: D000818:Animals; D001369:Axons / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure; D001692:Biological Transport / Q000502:physiology; D015415:Biomarkers / Q000378:metabolism; D015220:Calcium Channels / Q000235:genetics / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D005727:Ganglia, Spinal / Q000166:cytology; D006056:Golgi Apparatus / Q000378:metabolism*; D064428:Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels; D008297:Male; D009416:Nerve Regeneration / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D015221:Potassium Channels / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D055571:Secretory Pathway / Q000502:physiology*; D014982:Xenopus laevis / Q000502:physiology; D020864:Calcium Channels, N-Type
chemical_list: D015415:Biomarkers; D015220:Calcium Channels; D064428:Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels; D009419:Nerve Tissue Proteins; D015221:Potassium Channels; C491367:Cacna1a protein, rat; D020864:Calcium Channels, N-Type; C114265:Faim2 protein, rat; C513836:HCN4 protein, rat