Neuron Replating, a Powerful and Versatile Approach to Study Early Aspects of Neuron Differentiation

Schneider, Friedhelm; Duong, Thuy-An; Rust, Marco B.

doi:10.1523/eneuro.0536-20.2021

Cited by 8 publications

(6 citation statements)

References 34 publications

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“…While we here implicated CAP1 in synaptic actin regulation, we earlier showed its relevance for actin dynamics in growth cones [61,63]. We therefore conclude a general requirement of CAP1 in neuronal actin regulation both during differentiation and in differentiated neurons, similar to cofilin1 [2,14,45,55,57,62]. By PLA we found colocalization (within 40 nm) of CAP1 and cofilin1 in the dendritic compartment, and our co-immunoprecipitation experiments validated their physical interaction in the hippocampus, which required CAP1's HFD.…”

Section: Discussionsupporting

confidence: 80%

Functional interdependence of the actin regulators CAP1 and cofilin1 in control of dendritic spine morphology

Heinze

Schuldt

Khudayberdiev

et al. 2022

Preprint

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The vast majority of excitatory synapses are formed on small dendritic protrusions termed dendritic spines. Dendritic spines vary in size and density that are crucial determinants of excitatory synaptic transmission. Aberrations in spine morphogenesis can compromise brain function and have been associated with neuropsychiatric disorders. Actin filaments (F-actin) are the major structural component of dendritic spines and therefore actin-binding proteins (ABP) that control F-actin dis-/assembly moved into the focus as critical regulators of brain function. Studies of the past decade identified the ABP cofilin1 as a key regulator of spine morphology, synaptic transmission and behavior, and they emphasized the necessity for a tight control of cofilin1 to ensure proper brain function. Here, we report spine enrichment of cyclase-associated protein 1 (CAP1), a conserved multidomain protein with largely unknown physiological functions. Super-resolution microscopy and live cell imaging of CAP1-deficient hippocampal neurons revealed impaired synaptic F-actin organization and dynamics associated with alterations in spine morphology. Mechanistically, we found that CAP1 cooperates with cofilin1 in spines and that its helical folded domain is relevant for this interaction. Moreover, our data proved functional interdependence of CAP1 and cofilin1 in control of spine morphology. In summary, we identified CAP1 as a novel regulator of the postsynaptic actin cytoskeleton that is essential for synaptic cofilin1 activity.

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Section: Discussionsupporting

confidence: 80%

Functional interdependence of the actin regulators CAP1 and cofilin1 in control of dendritic spine morphology

Heinze

Schuldt

Khudayberdiev

et al. 2022

Preprint

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“…By exploiting cortical neurons from gene-targeted mice, the present study aimed at identifying ABPs that act upstream of neuronal MRTF-SRF signaling. Because previous studies identified members of the actin-depolymerizing factor (ADF)/cofilin family of actin-depolymerizing proteins as essential regulators of the neuronal actin cytoskeleton relevant for brain development, synapse physiology, and behavior (18)(19)(20)(21)(22)(23)(24)(25)(26), we did not expect to find neuronal MRTF-SRF activity unchanged upon inactivation of either cofilin1 or ADF and only slightly increased upon inactivation of both ADF/cofilin proteins. Instead, SRF activity was strongly increased upon inactivation of cyclase-associated protein 1 (CAP1) but not of its homolog CAP2.…”

Section: Introductionmentioning

confidence: 90%

“…Primary cortical neurons from E18 mice of both sexes were prepared as previously described ( 26 ). In brief, cerebral cortices from the same litter were pooled together, treated with TrypLE Express (Gibco) for 6 min at 37°C, and dissociated with pipetting up and down six or seven times.…”

Section: Methodsmentioning

confidence: 99%

The actin-binding protein CAP1 represses MRTF-SRF–dependent gene expression in mouse cerebral cortex

Khudayberdiev,

Weiss,

Heinze

et al. 2024

Sci. Signal.

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Serum response factor (SRF) is an essential transcription factor for brain development and function. Here, we explored how an SRF cofactor, the actin monomer-sensing myocardin-related transcription factor MRTF, is regulated in mouse cortical neurons. We found that MRTF-dependent SRF activity in vitro and in vivo was repressed by cyclase-associated protein CAP1. Inactivation of the actin-binding protein CAP1 reduced the amount of actin monomers in the cytoplasm, which promoted nuclear MRTF translocation and MRTF-SRF activation. This function was independent of cofilin1 and actin-depolymerizing factor, and CAP1 loss of function in cortical neurons was not compensated by endogenous CAP2. Transcriptomic and proteomic analyses of cerebral cortex lysates from wild-type and Cap1 knockout mice supported the role of CAP1 in repressing MRTF-SRF–dependent signaling in vivo. Bioinformatic analysis identified likely MRTF-SRF target genes, which aligned with the transcriptomic and proteomic results. Together with our previous studies that implicated CAP1 in axonal growth cone function as well as the morphology and plasticity of excitatory synapses, our findings establish CAP1 as a crucial actin regulator in the brain relevant for formation of neuronal networks.

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“…The copyright holder for this preprint this version posted February 28, 2024. ; https://doi.org/10.1101/2024.02.26.582060 doi: bioRxiv preprint previous studies let members of the actin-depolymerizing factor (ADF)/cofilin family emerge as essential regulators of the neuronal actin cytoskeleton relevant for brain development, synapse physiology and behavior (Bellenchi et al, 2007;Hotulainen et al, 2009;Rust et al, 2010;Flynn et al, 2012;Goodson et al, 2012;Wolf et al, 2015;Zimmermann et al, 2015;Sungur et al, 2018;Schneider et al, 2021a), we were surprised to find them largely dispensable for neuronal MRTF-SRF activity.…”

Section: Introductionmentioning

confidence: 97%

“…By exploiting cortical neurons from gene-targeted mice, the present study aimed at identifying ABP that act upstream of neuronal MRTF-SRF signaling. Because previous studies let members of the actin-depolymerizing factor (ADF)/cofilin family emerge as essential regulators of the neuronal actin cytoskeleton relevant for brain development, synapse physiology and behavior (Bellenchi et al, 2007; Hotulainen et al, 2009; Rust et al, 2010; Flynn et al, 2012; Goodson et al, 2012; Wolf et al, 2015; Zimmermann et al, 2015; Sungur et al, 2018; Schneider et al, 2021a), we were surprised to find them largely dispensable for neuronal MRTF-SRF activity. Instead, SRF activity was strongly increased upon inactivation of cyclase-associated protein 1 (CAP1), but not of its homolog CAP2.…”

Section: Introductionmentioning

confidence: 99%

Cyclase-associated protein 1 (CAP1) represses MRTF-SRF-dependent gene expression in the mouse cerebral cortex

Khudayberdiev,

Weiss,

Heinze

et al. 2024

Preprint

Self Cite

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Serum response factor (SRF) is a ubiquitously expressed transcription factor essential for brain development and function. SRF activity is controlled by two competing classes of coactivators, myocardin-related transcription factors (MRTF) and ternary complex factors (TCF), which introduce specificity into gene expression programs. To date, only few brain studies investigated upstream regulatory mechanisms, which mainly focused on TCF. Since an inhibitory function of monomeric actin towards MRTF-SRF signaling is well-established, we hypothesized a regulatory role for the key actin regulator ADF/cofilin. Surprisingly, ADF/cofilin was largely dispensable for neuronal MRTF-SRF activity. Instead, reporter assays combined with pharmacological and genetic approaches in isolated mouse neurons identified cyclase-associated protein 1 (CAP1) as an important regulator of this pathway. CAP1 promotes cytosolic MRTF retention and represses neuronal MRTF-SRF signaling via an actin-dependent mechanism that requires two specific protein domains. Further, deep RNA sequencing and mass spectrometry in mutant mice proved CAP1's in vivo relevance for this pathway in the cerebral cortex, and led to the identification of neuronal MRTF-SRF target genes. Together, we identified CAP1 as a novel and crucial repressor of neuronal MRTF-SRF signaling.

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Neuron Replating, a Powerful and Versatile Approach to Study Early Aspects of Neuron Differentiation

Cited by 8 publications

References 34 publications

Functional interdependence of the actin regulators CAP1 and cofilin1 in control of dendritic spine morphology

Functional interdependence of the actin regulators CAP1 and cofilin1 in control of dendritic spine morphology

The actin-binding protein CAP1 represses MRTF-SRF–dependent gene expression in mouse cerebral cortex

Cyclase-associated protein 1 (CAP1) represses MRTF-SRF-dependent gene expression in the mouse cerebral cortex

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