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bioRxiv · 10.1101/492769

Netrin/UNC-6 triggers actin assembly and non-muscle myosin activity to drive dendrite retraction in the self-avoidance response.

Sundararajan, L.·Smith, C.·Watson, J.·Millis, B.·Tyska, M.·Miller, D.
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Abstract

Dendrite growth is constrained by the self-avoidance response but the downstream pathways that balance these opposing mechanisms are unknown. We have proposed that the diffusible cue UNC-6(Netrin) is captured by UNC-40 (DCC) for a short-range interaction with UNC-5 to trigger self-avoidance in the C. elegans PVD neuron. Here we report that the actin-polymerizing proteins UNC-34(Ena/VASP), WSP-1(WASP), UNC-73(Trio), MIG-10(Lamellipodin) and the Arp2/3 complex effect dendrite retraction in the self-avoidance response mediated by UNC-6(Netrin). The paradoxical idea that actin polymerization results in shorter rather than longer dendrites is explained by our finding that NMY-1 (non-muscle myosin II) is necessary for retraction and could therefore mediate this effect in a contractile mechanism. Our results also show that dendrite length is determined by the antagonistic effects on the actin cytoskeleton of separate sets of effectors for retraction mediated by UNC-6(Netrin) versus outgrowth promoted by the DMA-1 receptor. Thus, our findings suggest that the dendrite length depends on an intrinsic mechanism that balances distinct modes of actin assembly for growth versus retraction.

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Sundararajan, L., Smith, C., Watson, J., Millis, B., Tyska, M., Miller, D.. 2018-12-10. Netrin/UNC-6 triggers actin assembly and non-muscle myosin activity to drive dendrite retraction in the self-avoidance response.. https://doi.org/10.1101/492769

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