Figure 1. Impaired synaptic connectivity in α2δ-1–deficient cortex. (A) Top: Western blot of α2δ-1 expression from WT cortex and hippocampus from postnatal day (PND) 1 to adult. Tubulin: loading control. Bottom: α2δ-1 expression as fold change More about this image found in Impaired synaptic connectivity in α2δ-1–deficient cortex. (A) Top: Western...

Figure 2. Lack of α2δ-1 results in decreased excitatory synaptic function. (A) Recordings were made from LII/III pyramidal neurons in V1 at P21. (B) mEPSC traces from WT and α2δ-1 KO pyramidal neurons. (C and D) Frequency (C, left), More about this image found in Lack of α2δ-1 results in decreased excitatory synaptic function. (A) Recor...

Figure 3. Ultrastructural analysis reveals that α2δ-1 promotes synapse and spine maturation. (A) Electron micrographs from P21 V1 WT and α2δ-1 KO brains. Arrows, excitatory synapses. Bar, 1 µm. (B) ssEM 3D reconstructions of LI dendrites from More about this image found in Ultrastructural analysis reveals that α2δ-1 promotes synapse and spine matu...

Figure 4. α2δ-1 promotes synapse and spine development cell autonomously. (A) Schematic for in utero electroporation. (B) Confocal image of P21 V1. Cre⁺ neurons in LII/III express RTm. Dendrites were imaged in the S/Z. (C) Workflow for More about this image found in α2δ-1 promotes synapse and spine development cell autonomously. (A) Schema...

Figure 5. TSP stimulates synaptogenesis via postsynaptic α2δ-1. (A) Mouse cortical neuron purification and TSP2 treatment timeline. (B) Cortical dendrites from α2δ-1 Het or KO mouse pups. Cells were treated with TSP2-containing or deficient More about this image found in TSP stimulates synaptogenesis via postsynaptic α2δ-1. (A) Mouse cortical n...

Figure 6. TSP-induced synapse formation requires Rho GTPase Rac1. (A) Rat cortical neuron purification and TSP2 treatment timeline. (B) Rat cortical neurons transfected with a pX601 vector containing saCas9 and sgRNA identified by HA More about this image found in TSP-induced synapse formation requires Rho GTPase Rac1. (A) Rat cortical n...

Figure 7. Rac1 promotes synaptic development and spinogenesis downstream of α2δ-1. (A) Schematic for organotypic slice culture/biolistic transfection. GFP⁺ dendrites (blue) are imaged at high magnification by confocal microscopy to capture spine More about this image found in Rac1 promotes synaptic development and spinogenesis downstream of α2δ-1. (A...

Figure 8. α2δ-1 and Rac1 work in concert to rescue synapses and spines in α2δ-1–null cortex. (A) 3D confocal images (top) and Imaris reconstructions (bottom) of GFP⁺ dendrites in the S/Z of DEV19 (i.e., P21) organotypic slices from α2δ-1 Het or More about this image found in α2δ-1 and Rac1 work in concert to rescue synapses and spines in α2δ-1–null ...

Figure 9. Model for α2δ-1’s dual role in promoting synapse and spine development. Early on, α2δ-1 is present on filopodia seeking contact with axonal partners. Rac1 is predominantly bound to GDP, rendering it inactive. After TSP binding, (1) More about this image found in Model for α2δ-1’s dual role in promoting synapse and spine development. Ea...

Figure 1. Distribution and dynamics of actin blobs in dendrites. (A) Distribution of LifeAct (green) expressed by ppk-GAL4 in dendritic arbors of class IV da neurons marked by ppk-CD4-tdTomato (magenta). Arrows indicate high LifeAct signals in More about this image found in Distribution and dynamics of actin blobs in dendrites. (A) Distribution of...