Drosophila Dendritic Arborisation Neurons: Fantastic Actin Dynamics and Where to Find Them

Abstract

Neuronal dendrites receive, integrate, and process numerous inputs and therefore serve as the neuron’s “antennae”. Dendrites display extreme morphological diversity across different neuronal classes to match the neuron’s specific functional requirements. Understanding how this structural diversity is specified is therefore important for shedding light on information processing in the healthy and diseased nervous system. Popular models for in vivo studies of dendrite differentiation are the four classes of dendritic arborization (c1da–c4da) neurons of Drosophila larvae with their class-specific dendritic morphologies. Using da neurons, a combination of live-cell imaging and computational approaches have delivered information on the distinct phases and the time course of dendrite development from embryonic stages to the fully developed dendritic tree. With these data, we can start approaching the basic logic behind differential dendrite development. A major role in the definition of neuron-type specific morphologies is played by dynamic actin-rich processes and the regulation of their properties. This review presents the differences in the growth programs leading to morphologically different dendritic trees, with a focus on the key role of actin modulatory proteins. In addition, we summarize requirements and technological progress towards the visualization and manipulation of such actin regulators in vivo.

Augmin complex activity finetunes dendrite morphology through non-centrosomal microtubule nucleation in vivo

“…This morphological diversity depends on the expression of specific combinations of cytoskeletal regulators that temporally and locally promote a specific branching pattern ( Nanda et al, 2020 ; Stürner et al, 2022 ). Although a few neuron type-specific actin regulators that determine type-specific morphological characteristics have been uncovered, less is known about neuron type-specific MT nucleation mechanisms ( Coles and Bradke, 2015 ; Kilo et al, 2021 ; Tavosanis, 2021 ; Stürner et al, 2022 ). Multiple lines of evidence together indicate that there is a cooperation between the γ-TuRC and augmin promoting neurite elaboration in cultured hippocampal neurons.…”

“…The cytoskeleton is essential for dendrite elaboration. Although actin is involved in the dynamics that support dendrite branching and elaboration, microtubules (MTs) are thought to promote the stabilization of branch subsets ( Delandre et al, 2016 ; Nanda et al, 2020 ; Kilo et al, 2021 ). MTs are polarized polymers nucleating from microtubule-organizing centers (MTOCs) ( González et al, 1998 ; Sanchez and Feldman, 2017 ; Wu and Akhmanova, 2017 ).…”

The Zinc-BED Transcription Factor Bedwarfed Promotes Proportional Dendritic Growth and Branching through Transcriptional and Translational Regulation in Drosophila

“…Cell type-specific dendritic architecture is mediated by the organization and dynamics of cytoskeletal fibers [ 26 , 29 , 35 , 36 ]. In the case of Drosophila md neurons, previous studies have demonstrated that the local distribution and organization of microtubules (MT) and F-actin fibers are sufficient for constraining arbor morphology [ 37 ].…”

The Zinc-BED transcription factor Bedwarfed promotes proportional dendritic growth and branching through transcriptional and translational regulation inDrosophila

“…Cell-type specific dendritic architecture is mediated by the organization and dynamics of cytoskeletal fibers (Das et al ., 2017; Das et al ., 2021; Kilo et al ., 2021; Bhattacharjee et al ., 2022). In the case of Drosophila md neurons, previous studies have demonstrated that the local distribution and organization of microtubule (MT) and F-actin fibers is sufficient in constraining arbor morphology (Nanda et al ., 2020).…”