Handling Editor: François Guillemot
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.
Footnotes
Competing interests
The authors declare no competing or financial interests.
Author contributions
Conceptualization: F.Y.; Methodology: M.R., L.Y.C.; Validation: M.R., F.Y.; Formal analysis: M.R., S.B., L.Y.C., Q.W., F.Y.; Investigation: M.R., S.B., L.Y.C., Q.W., F.Y.; Resources: M.R., S.B., Q.W.; Data curation: M.R.; Writing - original draft: M.R., F.Y.; Writing - review & editing: F.Y.; Visualization: M.R., S.B., L.Y.C., Q.W.; Supervision: F.Y.; Project administration: F.Y.; Funding acquisition: F.Y.
Funding
This work was funded by the Temasek Life Sciences Laboratory Singapore (TLL-2040) and by the National Research Foundation Singapore (SBP-P3 and SBP-P8) (both to F.Y.).
Supplementary information
Supplementary information available online at https://dev.biologists.org/lookup/doi/10.1242/dev.191155.supplemental
- Received April 3, 2020.
- Accepted September 8, 2020.
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