The membrane protein Raw regulates dendrite pruning via the secretory pathway

Development. 2020 Oct 9;147(19):dev191155. doi: 10.1242/dev.191155.

Abstract

Neuronal pruning is essential for proper wiring of the nervous systems in invertebrates and vertebrates. Drosophila ddaC sensory neurons selectively prune their larval dendrites to sculpt the nervous system during early metamorphosis. However, the molecular mechanisms underlying ddaC dendrite pruning remain elusive. Here, we identify an important and cell-autonomous role of the membrane protein Raw in dendrite pruning of ddaC neurons. Raw appears to regulate dendrite pruning via a novel mechanism, which is independent of JNK signaling. Importantly, we show that Raw promotes endocytosis and downregulation of the conserved L1-type cell-adhesion molecule Neuroglian (Nrg) prior to dendrite pruning. Moreover, Raw is required to modulate the secretory pathway by regulating the integrity of secretory organelles and efficient protein secretion. Mechanistically, Raw facilitates Nrg downregulation and dendrite pruning in part through regulation of the secretory pathway. Thus, this study reveals a JNK-independent role of Raw in regulating the secretory pathway and thereby promoting dendrite pruning.

Keywords: Axon; Dendrite; JNK signaling; Neuroglian; Pruning; Raw.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Adhesion Molecules, Neuronal / genetics
  • Cell Adhesion Molecules, Neuronal / metabolism
  • Cytoskeletal Proteins / genetics
  • Cytoskeletal Proteins / metabolism*
  • Drosophila Proteins / genetics
  • Drosophila Proteins / metabolism*
  • Drosophila melanogaster
  • Endocytosis / genetics
  • Endocytosis / physiology
  • Gene Expression Regulation, Developmental / genetics
  • Gene Expression Regulation, Developmental / physiology
  • Metamorphosis, Biological / genetics
  • Metamorphosis, Biological / physiology
  • Secretory Pathway / genetics
  • Secretory Pathway / physiology
  • Sensory Receptor Cells / cytology*
  • Sensory Receptor Cells / metabolism*

Substances

  • Cell Adhesion Molecules, Neuronal
  • Cytoskeletal Proteins
  • Drosophila Proteins
  • raw protein, Drosophila
  • Nrg protein, Drosophila