Biology subjects

Myers, K. R.

Publications and source records attributed to Myers, K. R..

4 recordsLinked to original sources

bioRxiv2025

Localization of Fascin to Dendritic Protrusions Regulates Postsynaptic Plasticity

The Fascin family of actin-bundling proteins is best known for organizing actin filaments (F-actin) into tightly packed bundles that drive dynamic membrane protrusions such as filopodia. In neurons, fascin has been thought to primarily function in axons, as previous studies reported its absence from dendritic filopodia and spines. Here, we demonstrate that fascin is both present and functionally important in dendritic compartments. Using optimized immunocytochemistry and CRISPR-based endogenous tagging of fascin1 in cultured hippocampal neurons, we show that fascin is concentrated in developing dendritic filopodia and enriched in mature dendritic spines. Super- resolution imaging further reveals that fascin is organized into discrete nanoscale foci within spine heads, but not the spine neck. Finally, we show that CRISPR-mediated knockout of fascin1 in mature hippocampal neurons impairs synaptic potentiation, without affecting baseline excitatory synaptic transmission. Together, our findings uncover a previously overlooked aspect of actin organization in dendritic spines and establish fascin as a critical regulator of postsynaptic plasticity. Summary StatementThe actin bundling protein fascin localizes to dendritic filopodia and spines, where it regulates activity-dependent synaptic plasticity.

neuroscience↗

bioRxiv2025

A Critical Role for the Fascin Family of Actin Bundling Proteins in Axon Development, Brain Wiring and Function

Actin-based cell motility drives many neurodevelopmental events including guided axonal growth. Fascin is a major family of F-actin bundling proteins, but its role in axon development in vivo and brain wiring remains unclear. Here, we report that fascin is required for axon development, brain wiring and function. We show that fascin is enriched in the motile filopodia of axonal growth cones and its inhibition impairs axonal extension and branching of hippocampal neurons in culture. We next provide evidence that fascin is essential for axon development and brain wiring in vivo using Drosophila melanogaster as a model. Drosophila expresses a single ortholog of mammalian fascin called Singed (SN), which is expressed in the mushroom body (MB) of the central nervous system. Loss of SN causes severe MB disruption, marked by - and {beta}-lobe defects indicative of altered axonal guidance. SN-null flies also exhibit defective sensorimotor behaviors as assessed by the negative geotaxis assay. MB-specific expression of SN in SN-null flies rescues MB structure and sensorimotor deficits, indicating that SN functions autonomously in MB neurons. Together, our data from primary neuronal culture and in vivo models highlight a critical role for fascin in brain development and function. HighlightsO_LIFascin regulates axon growth and branching of hippocampal neurons in culture. C_LIO_LISinged, a Drosophila fascin ortholog, is enriched in mushroom body (MB) axons. C_LIO_LISinged loss causes axon guidance defects and sensorimotor issues in flies. C_LIO_LIMB-specific Singed re-expression rescues MB structure and behavior in flies. C_LI

cell biology↗

bioRxiv2020

The Polyadenosine RNA Binding Protein ZC3H14 is Required in Mice for Proper Dendritic Spine Density

ZC3H14 (Zinc finger CysCysCysHis domain-containing protein 14), an evolutionarily conserved member of a class of tandem zinc finger (CCCH) polyadenosine (polyA) RNA binding proteins, is associated with a form of heritable, nonsyndromic autosomal recessive intellectual disability. Previous studies of a loss of function mouse model, Zc3h14{Delta}ex13/{Delta}ex13, provide evidence that ZC3H14 is essential for proper brain function, specifically for working memory. To expand on these findings, we analyzed the dendritic spines of hippocampal neurons from Zc3h14{Delta}ex13/{Delta}ex13 mice. These studies reveal that loss of ZC3H14 does not affect dendritic spine density in either CA1 pyramidal neurons or dentate gyrus granule cells in the hippocampus. However, overexpression of ZC3H14 in cultured hippocampal neurons increases the overall density of spines. We next performed biochemical analyses of synaptosomes prepared from whole wild-type and Zc3h14{Delta}ex13/{Delta}ex13 mouse brains to determine if there are changes in steady state levels of postsynaptic proteins upon the loss of ZC3H14. We found that ZC3H14 is present within synaptosomes and that a crucial postsynaptic protein, CaMKII, is significantly increased in these synaptosomal fractions upon loss of ZC3H14. Together, these results demonstrate that ZC3H14 localizes to synapses, that its levels influence dendritic spine morphology, and that its loss dysregulates synaptic CaMKII levels, suggesting a potential role for ZC3H14 in synaptic function and plasticity.

neuroscience↗

bioRxiv2019

VE-cadherin endocytosis controls vascular integrity and patterning during development

Tissue morphogenesis requires dynamic intercellular contacts that are subsequently stabilized as tissues mature. The mechanisms governing these competing adhesive properties are not fully understood. Using gain- and loss-of-function approaches, we tested the role of p120-catenin (p120) and VE-cadherin (VE-cad) endocytosis in vascular development using mouse mutants that exhibit increased (VE-cadGGG/GGG) or decreased (VE-cadDEE/DEE) internalization. VE-cadGGG/GGG mutant mice exhibited reduced VE-cad-p120 binding, reduced VE-cad levels, microvascular hemorrhaging, and decreased survival. By contrast, VE-cadDEE/DEE mutants exhibited normal vascular permeability but displayed microvascular patterning defects. Interestingly, VE-cadDEE/DEE mutant mice did not require endothelial p120, demonstrating that p120 is dispensable in the context of a stabilized cadherin. In vitro, VE-cadDEE mutant cells displayed defects in polarization and cell migration that were rescued by uncoupling VE-cadDEE from actin. These results indicate that cadherin endocytosis coordinates cell polarity and migration cues through actin remodeling. Collectively, our results indicate that regulated cadherin endocytosis is essential for both dynamic cell movements and establishment of stable tissue architecture.\n\nSummary StatementThis study uses mouse genetic and in vitro approaches to demonstrate that cadherin endocytosis is critical for the formation of blood vessels during development by promoting actin-dependent collective cell migration, whereas the inhibition of this endocytosis by p120 binding is essential for vessel stabilization.

cell biology↗