Dendrite arbor pattern determines the functional characteristics of a neuron. It is founded on primary branch structure, defined through cell intrinsic and transcription-factor-encoded mechanisms. Developing arbors have extensive acentrosomal microtubule dynamics, and here, we report an unexpected role for the atypical actin motor Myo6 in creating primary branch structure by specifying the position, polarity, and targeting of these events. We carried out in vivo time-lapse imaging of Drosophila adult sensory neuron differentiation, integrating machine-learning-based quantification of arbor patterning with molecular-level tracking of cytoskeletal remodeling. This revealed that Myo6 and the transcription factor Knot regulate transient surges of microtubule polymerization at dendrite tips; they drive retrograde extension of an actin filament array that specifies anterograde microtubule polymerization and guides these microtubules to subdivide the tip into multiple branches. Primary branches delineate functional compartments; this tunable branching mechanism is key to define and diversify dendrite arbor compartmentalization.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/j.neuron.2020.02.002 | DOI Listing |
Unlabelled: Cell shape is crucial to cell function, particularly in neurons. The cross-sectional diameter, also known as caliber, of axons and dendrites is an important parameter of neuron shape, best appreciated for its influence on the speed of action potential propagation. Most studies of axon caliber focus on cell-wide regulation and assume that caliber is static.
View Article and Find Full Text PDFHear Res
December 2024
Eaton-Peabody Laboratories, Massachusetts Eye and Ear, Boston, MA, United States; Department of Otolaryngology-Head & Neck Surgery, Harvard Medical School, Boston, MA, United States. Electronic address:
Auditory-nerve fibers (ANFs) from a given cochlear region can vary in threshold sensitivity by up to 60 dB, corresponding to a 1000-fold difference in stimulus level, although each fiber innervates a single inner hair cell (IHC) via a single synapse. ANFs with high-thresholds also have low spontaneous rates (SRs) and synapse on the side of the IHC closer to the modiolus, whereas the low-threshold, high-SR fibers synapse on the side closer to the pillar cells. Prior biophysical work has identified modiolar-pillar differences in both pre- and post-synaptic properties, but a comprehensive explanation for the wide range of sensitivities remains elusive.
View Article and Find Full Text PDFFront Neural Circuits
December 2024
Laboratory of Mammalian Neural Circuits, National Institute of Genetics, Mishima, Japan.
The Golgi apparatus is a central hub in the intracellular secretory pathway. By positioning in the specific intracellular region and transporting materials to spatially restricted compartments, the Golgi apparatus contributes to the cell polarity establishment and morphological specification in diverse cell types. In neurons, the Golgi apparatus mediates several essential steps of initial neural circuit formation during early brain development, such as axon-dendrite polarization, neuronal migration, primary dendrite specification, and dendritic arbor elaboration.
View Article and Find Full Text PDFProg Neuropsychopharmacol Biol Psychiatry
December 2024
Department of Biomedical Sciences, University of Guelph, 50 Stone Rd. E., Guelph, Ontario N1G 2W1, Canada. Electronic address:
There are substantial differences in the characteristics of males and females with an autism spectrum disorder (ASD), yet there is little knowledge surrounding the mechanistic underpinnings of these differences. The valproic acid (VPA) rodent model is based upon the human fetal valproate spectrum disorder, which is associated with increased risk of developing ASD. This model, which displays significant social, learning, and memory alterations, has therefore been widely used to further our understanding of specific biological features of ASD.
View Article and Find Full Text PDFCell Signal
December 2024
Research Service, Edward Hines Jr. Veterans Administration Hospital, Hines, IL, USA; Department of Molecular Pharmacology and Neuroscience, Loyola University Chicago, Health Sciences Division, Maywood, IL, USA.
The nerve growth factor (NGF) receptor TrkA is a tightly regulated receptor tyrosine kinase that activates neuronal signaling pathways promoting cell survival in addition to axonal and dendritic outgrowth. Previously, we showed that NGF and TrkA signaling is altered in neuron-like PC12 cells that overexpress Nogo-A, a protein known to influence axonal outgrowth and dendritic arborization associated with neuronal plasticity. In the present report, we provide evidence for changes in NGF-mediated receptor-level and downstream signaling that occur in cells overexpressing Nogo-A.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!