Biology subjects

Sudhof, T. C.

Publications and source records attributed to Sudhof, T. C..

22 records · Page 2Linked to original sources

bioRxiv2020

Structure of the teneurin-latrophilin complex: Alternative splicing controls synapse specificity by a novel mechanism

The trans-synaptic interaction of the cell-adhesion molecules teneurins (Tenms) with latrophilins (Lphns) promotes excitatory synapse formation when Lphns simultaneously interact with FLRTs. Insertion of a short alternatively-spliced region within Tenms abolishes the Tenm-Lphn interaction and switches Tenm function to specify inhibitory synapses. How Tenms bind to Lphns in a manner regulated by alternative splicing remains unclear. Here, we report the high-resolution cryo-EM structure of the Tenm2-Lphn3 complex, and describe the trimeric Tenm2-Lphn3-FLRT3 complex. The structure reveals that the N-terminal lectin-like domain of Lphn3 binds to the Tenm2 barrel at a site far away from the alternatively-spliced region. Alternative-splicing regulates the Tenm2-Lphn3 interaction by hindering access to the Lphn-binding surface rather than altering it. Strikingly, mutagenesis of the Lphn-binding surface of Tenm2 abolishes the Lphn3 interaction and impairs excitatory but not inhibitory synapse formation. These results suggest that a multi-level coincident binding mechanism mediated by a cryptic adhesion complex between Tenms and Lphns regulates synapse specificity.

biochemistry↗

bioRxiv2019

Persistent transcriptional programs are associated with remote memory in diverse cells of the medial prefrontal cortex

It is thought that memory is stored in engrams, a subset of neurons that undergo learning-induced alterations. The role of gene-expression during learning and short-term memory has been studied extensively, but little is known about remote memory that can persist for a lifetime. Using long-term contextual fear memory as a paradigm, an activity-dependent transgenic model for engram-specific labeling, and single-cell transcriptomics we probed the gene-expression landscape underlying remote memory consolidation and recall in the medial prefrontal cortex. Remarkably, we find sustained activity-specific transcriptional alterations in diverse populations of neurons that persist even weeks after fear-learning and are distinct from those previously identified in learning. Out of a vast plasticity-coding space, we uncover select membrane-fusion genes that could play important roles in maintaining remote memory traces. Unexpectedly, astrocytes and microglia also acquire new persistent gene signatures upon recall of remote memory, suggesting that they actively contribute to memory circuits. Our discovery of novel distinct gene-expression programs involved in long term memory adds an important dimension of activity-dependent cellular states to existing brain taxonomy atlases and sheds light on the elusive mechanisms of remote memory storage.

neuroscience↗

bioRxiv2019

A toolbox of nanobodies developed and validated for diverse neuroscience research applications

Nanobodies (nAbs) are small, minimal antibodies that have distinct attributes that make them uniquely suited for certain biomedical research, diagnostic and therapeutic applications. Prominent uses include as intracellular antibodies or intrabodies to bind and deliver cargo to specific proteins and/or subcellular sites within cells, and as nanoscale immunolabels for enhanced tissue penetration and improved spatial imaging resolution. Here, we report the generation and validation of nAbs against a set of proteins prominently expressed at specific subcellular sites in brain neurons. We describe a novel hierarchical validation pipeline to systematically evaluate nAbs isolated by phage display for effective and specific use as intrabodies and immunolabels in mammalian cells including brain neurons. These nAbs form part of a robust toolbox for targeting proteins with distinct and highly spatially-restricted subcellular localization in mammalian brain neurons, allowing for visualization and/or modulation of structure and function at those sites.

neuroscience↗

bioRxiv2019

Discrete and Continuous Cell Identities of the Adult Murine Striatum

The striatum is a large brain region containing two major cell types: D1 (dopamine receptor 1) and D2 (dopamine receptor 2) expressing spiny projection neurons (SPNs). We generated a cell type atlas of the adult murine striatum using single-cell RNA-seq of SPNs combined with quantitative RNA in situ hybridization (ISH). We developed a novel computational pipeline that distinguishes discrete versus continuous cell identities in scRNA-seq data, and used it to show that SPNs in the striatum can be classified into four discrete types that reside in discrete anatomical clusters or are spatially intermingled. Within each discrete type, we find multiple independent axes of continuous cell identity that map to spatial gradients and whose genes are conserved between discrete types. These gradients correlate well to previously-mapped gradients of connectivity. Using these insights, we discovered multiple novel spatially localized region of the striatum, one of which contains patch-D2 SPNs that express Tac1, Htr7, and Th. Intriguingly, we found one subtype that strongly co-expresses both D1 and D2 dopamine receptors, and uniquely expresses a rare D2 receptor splice variant. These results collectively suggest an organizational principal of neuron identity in which major neuron types can be separated into discrete classes with little overlap and no implied spatial relationship. However these discrete classes are then continuously subdivided by multiple spatial gradients of expression defining anatomical location via a combinatorial mechanism. Finally, they suggest that neuronal circuitry has a substructure at far higher resolution than is typically interrogated which is defined by the precise identity and location of a neuron.

neuroscience↗