Biology subjects

Webb, B. D.

Publications and source records attributed to Webb, B. D..

4 recordsLinked to original sources

bioRxiv2025

Structural Interactions of Ankyrin B with NrCAM and β2 Spectrin

Ank2 is a high confidence autism spectrum disorder (ASD) gene encoding the spectrin-actin scaffold protein Ankyrin B (AnkB). The 220 kDal isoform of AnkB has multiple functions including developmental spine pruning through L1 family cell adhesion molecules (L1-CAMs) and class 3 Semaphorins on dendrites of pyramidal neurons to achieve an appropriate excitatory balance in the neocortex. Molecular modeling employing AlphaFold was used to predict the structure and interactions of AnkB with the cytoplasmic domain of Neuron-glial Related L1-CAM (NrCAM), and with {beta}2-Spectrin. The validity of the models was assessed by analyzing protein-protein interactions by co-immunoprecipitation from HEK293 cell lysates after mutating key residues in AnkB predicted to impair these associations. Results revealed a pocket with critical residues in the AnkB membrane-binding domain that engages NrCAM at the conserved cytoplasmic motif FIGQY. Alphafold modeling of the AnkB/{beta}2-Spectrin complex also identified key interactions between the AnkB spectrin-binding domain and {beta}2-Spectrin repeats 14-15. Selected ASD-linked mutations in AnkB predicted to impact binding to NrCAM or {beta}2-Spectrin were then assayed for protein interactions. Maternally inherited ASD missense mutations AnkB A368G located in the NrCAM binding pocket and AnkB R977Q in the Zu51 subdomain disrupted associations with NrCAM and {beta}2-Spectrin, respectively. Moreover, AnkB A368G impaired the neuronal function of 220 kDal AnkB in Semaphorin 3F-induced spine pruning in mouse cortical neuron cultures. These new findings provide structural insights into the L1-CAM/AnkB complex and the molecular basis of ASD etiology associated with AnkB missense mutations.

neuroscience↗

bioRxiv2024

Perisomatic Synaptic Targeting by Cholecystokinin-Basket Interneurons through NrCAM and Ankyrin B

The perisomatic region of cortical pyramidal neurons (PNs) integrates local and long-range inputs and regulates firing. This domain receives GABAergic inputs from cholecystokinin (CCK)- and Parvalbumin (PV)-expressing basket cells (BCs) but how synaptic contacts are established is unclear. Neuron-glial related cell adhesion molecule (NrCAM) is a homophilic transmembrane protein that binds the scaffold protein Ankyrin B. Here we show that NrCAM and Ankyrin B mediate perisomatic synaptic contact between CCK-BCs and PNs in mouse medial prefrontal cortex (mPFC). Immunolabeling of CCK-BC terminals for vesicular glutamate transporter-3 (VGLUT3) or vesicular GABA transporter (VGAT) revealed a significant decrease in CCK-BC synaptic puncta on PN soma in NrCAM-null mice, however no decrease in PV-BC puncta or cell loss. VGLUT3+ CCK-BC puncta were also decreased by Ankyrin B deletion from PNs in Nex1Cre-ERT2:Ank2flox/flox:EGFP mice. A novel CCK-BC reporter mouse expressing tdTomato (tdT) at the Synuclein-{gamma} (Sncg) locus showed NrCAM localized to Sncg+ CCK-BCs, and to postsynaptic PN soma in Nex1Cre-ERT2:Ank2+/+:EGFP mice. Results suggest that NrCAM and Ankyrin B contribute to the establishment of connectivity between CCK-BCs and excitatory neurons of the mPFC.

neuroscience↗

bioRxiv2022

Inability to make facial expressions dampens emotion perception.

Humans rely heavily on facial expressions for social communication to convey their thoughts and emotions and to understand them in others. One prominent but controversial view is that humans learn to recognize the significance of facial expressions by mimicking the expressions of others. This view predicts that an inability to make facial expressions (e.g., facial paralysis) would result in reduced perceptual sensitivity to others facial expressions. To test this hypothesis, we developed a diverse battery of sensitive emotion recognition tasks to characterize emotion perception in individuals with Moebius Syndrome (MBS), a congenital neurological disorder that causes facial palsy. Using computer-based emotion detection tasks we systematically assessed emotion perception thresholds for static and dynamic face and body expressions. We found that while MBS individuals were able to perform challenging perceptual control tasks, they were less efficient at extracting emotion from facial expressions, compared to matched controls. Exploratory analyses of fMRI data from a small group of MBS participants suggested potentially reduced engagement of the amygdala in MBS participants during expression processing relative to matched controls. Collectively, these results support the role of facial mimicry and consequent facial feedback and motor experience in the perception of others expressions.

neuroscience↗

bioRxiv2019

Complex Autoinflammatory Syndrome Unveils Fundamental Principles of JAK1 Transcriptional and Biochemical Function

Autoinflammatory disease can result from monogenic errors of immunity. We describe herein the first example of a patient with early-onset widespread autoinflammation resulting from a mosaic, heterozygous, gain-of-function mutation (S703I) in JAK1, encoding a kinase essential for signaling downstream of over twenty-five cytokines. By first-of-its-kind custom single-cell RNA sequencing, we examine mosaicism with single cell resolution. We uncover that JAK1 transcription is predominantly restricted to a single allele across different immune cells, introducing the concept of a mutational \"transcriptotype\" that differs from the genotype. Functionally, the S703I mutation not only increased JAK1 kinase activity, but also resulted in transactivation of partnering JAKs, independently of its catalytic domain. Further, S703I JAK1 was not solely hypermorphic for cytokine signaling, but neomorphic as well, as it enabled downstream signaling cascades not canonically mediated by JAK1. Given these results, the patient was treated with tofacitinib, a JAK inhibitor, which led to rapid resolution of her clinical disease. Together, these findings represent an unprecedented degree of personalized medicine with the concurrent discovery of fundamental biological principles.

immunology↗