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Kim, H. B.

Publications and source records attributed to Kim, H. B..

2 recordsLinked to original sources

Stereotypic Neutralizing VH Clonotypes Against SARS-CoV-2 RBD in COVID-19 Patients and the Healthy Population

In six of seven severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) patients, VH clonotypes, encoded by either immunoglobin heavy variable (IGHV)3-53 or IGHV3-66 and immunoglobin heavy joining (IGHJ)6, were identified in IgG1, IgA1, and IgA2 subtypes, with minimal mutations, and could be paired with diverse light chains, resulting in binding to the SARS-CoV-2 receptor-binding domain (RBD). Because most human antibodies against the RBD neutralized the virus by inhibiting host cell entry, we selected one of these clonotypes and demonstrated that it could potently inhibit viral replication. Interestingly, these VH clonotypes pre-existed in six of 10 healthy individuals, predominantly as IgM isotypes, which could explain the expeditious and stereotypic development of these clonotypes among SARS-CoV-2 patients.One Sentence Summary Stereotypic-naïve SARS-CoV-2 neutralizing antibody clonotypes, encoded by IGHV3-53/IGHV3-66 and IGHJ6, were identified in most patients and pre-exist in the majority of the healthy population, predominantly as an IgM isotype.Competing Interest StatementThe authors have declared no competing interest.View Full Text

immunology

Size-dependent protein segregation creates a spatial switch for Notch and APP signaling

Aberrant cleavage of Notch by {gamma}-secretase is implicated in numerous diseases, but how cleavage is regulated in space and time is unclear. Here, we report that cadherin-based adherens junctions (cadAJs) are sites of high cell-surface {gamma}-secretase activity, as well as sites of constrained physical space that excludes {gamma}-secretase substrates having large extracellular domains (ECDs) like Notch. ECD shedding initiates drastic spatial relocalization of Notch to cadAJs, allowing enzyme-substrate interactions and downstream signaling. Spatial mutations by adjusting the ECD size or the physical constraint alter signaling. Dysregulation of this spatial switch promotes precocious differentiation of ventricular zone neural progenitor cells in vivo. We show the generality of this spatial switch for amyloid precursor protein proteolysis. Thus, cadAJs create spatially distinct biochemical compartments regulating cleavage events involving {gamma}-secretase and preventing aberrant activation of receptors. One Sentence SummaryNotch cleavage by {gamma}-secretase is regulated through dynamic spatial control of receptors, adhesion molecules, and activating proteases

cell biology