Biology subjects

Snyder, J. C.

Publications and source records attributed to Snyder, J. C..

5 recordsLinked to original sources

bioRxiv2026

P95-HER2 promotes metastatic progression by biasing MRTFA dependent signaling

Naturally occurring isoforms of the proto-oncogene Erb-B2 Receptor Tyrosine Kinase 2 (ERBB2, HER2) incite unique pathways of tumor progression in mouse models of breast cancer. Although each isoform has been shown to progress to metastasis, the N-terminally truncated isoform (p95) was previously shown to be biased toward early distant dissemination prior to detection. Here we show how HER2 isoforms differentially promote go-or-grow phenotypes through biased utilization of tyrosine autophosphorylation sites in the intracellular tail of HER2. Fluorescently barcoded humanized full-length HER2 (WT), exon-16 splice HER2 isoform (d16), and p95 expressing tumor cell lines were derived from HER2 Crainbow mice, then utilized for a series of functional assays including proliferation, tumor growth rate, cell motility, collective cell migration, cellular morphology, and invasive potential. Quantitative analysis reveals biased tumor cell behaviors across each genotype. WT tumor cells are biased toward proliferation and collective migration, d16 cells are biased toward proliferation and individual motility, and p95 tumor cells are biased toward individual motility and invasion. Single cell analysis reveals a myogenic-like state transition in p95 cells accompanied by an increased nuclear translocation of the Myocardin Related Transcription Factor A (MRTFA). MRTFA knockdown, as well as knockdown of a downstream effector, Transforming growth factor beta 1 induced transcript 1 (TGFB1I1), both inhibit the p95 invasive phenotype. Furthermore, intracellular residue tyrosine 1139 (Y1139) is necessary for MRTFA translocation, and when edited in p95 cells (Y1139F) invasion and motility phenotypes are subsequently lost. Our data illustrate the importance of functionally selective signaling in HER2 and highlight the need for therapeutics that intercept metastasis by targeting HER2 biased signaling.

cell biology↗

bioRxiv2025

CoSiDeX: A hyperspectral fluorescent protein resource for highly multiplexed imaging

Fluorescent proteins (FPs) have revolutionized spatiotemporal observations in biology. Yet, the design of multiplexed assays remains constrained by limited spectral characterization and palette validation. Although over 1,000 FPs have been catalogued, systematic resources for characterizing their use in multiplexed approaches are lacking. Here we present a resource and methodology for selecting and decoding FPs in multiplexed imaging experiments. A library of forty-four FPs was built for rapid assembly into mammalian expression vectors and transposase-mediated integration. Hyperspectral imaging was performed for each FP and spectral space was characterized mathematically. To support experimental design and data interpretation, we developed the Cosine Similarity Decoder of XFP (CoSiDeX) toolbox, to predict spectrally resolvable FP palettes and decode and re-color hyperspectral images. Using this approach, we demonstrate live-cell imaging of 12 uniquely labeled clones. Our work offers a scalable platform for selecting optimal FP palettes for multiplex experiments, with broad utility across diverse biological systems and hyperspectral imaging techniques.

molecular biology↗

bioRxiv2024

Nonlinear progression across the occult transition establishes cancer lethality

Cancer screening is based upon a linear model of neoplastic growth and malignant progression. Yet, historical observations suggest that malignant progression is uncoupled from growth which may explain the paradoxical increase in early-stage breast cancer detection without a dramatic reduction in metastatic burden. Here we lineage trace millions of genetically transformed field cells and thousands of screen detectable and symptomatic tumors using a cancer rainbow mouse model of HER2+ breast cancer. Transition rates from field cell to screen detectable tumor and then to symptomatic tumors were estimated from a dynamical model of tumor development. Field cells are orders of magnitude less likely to transition to a screen detectable tumor than the subsequent transition of a screen detectable tumor to a symptomatic tumor. Our model supports a critical occult transition in tumor development during which time a transformed cell becomes a bona fide neoplasm. Lineage tracing and test-by-transplantation reveals that nonlinear progression during or prior to the occult transition gives rise to nascent lethal cancers at screen detection. Simulations illustrate how occult transition rates are a critical determinant of tumor growth and malignancy in the lifetime of a host. Our data provides direct experimental evidence that cancers can deviate from the predictable linear progression model foundational to current screening paradigms

cancer biology↗

bioRxiv2023

Gut mucosal cells transfer α-synuclein to the vagus nerve

Epidemiological and histopathological findings have raised the possibility that misfolded -synuclein protein might spread from the gut to the brain and increase the risk of Parkinsons disease (PD). While past experimental studies in mouse models have relied on gut injections of exogenous recombinant -synuclein fibrils to study gut to brain -synuclein transfer, the possible origins of misfolded -synuclein within the gut have remained elusive. We recently demonstrated that sensory cells of the gut mucosa express -synuclein. In this study, we employed mouse intestinal organoids expressing human -synuclein to observe the transfer of -synuclein protein from gut epithelial cells in organoids co-cultured with vagal nodose neurons that are otherwise devoid of -synuclein expression. In intact mice that express pathological human -synuclein, but no mouse -synuclein, -synuclein fibril templating activity emerges in -synuclein seeded fibril aggregation assays in tissues from the gut, vagus nerve, and dorsal motor nucleus. In newly engineered transgenic mice that restrict pathological human -synuclein expression to intestinal epithelial cells, -synuclein fibril-templating activity transfers to the vagus nerve and to the dorsal motor nucleus. Subdiaphragmatic vagotomy prior to the induction of -synuclein expression in the gut epithelial cells effectively protects the hindbrain from the emergence of -synuclein fibril templating activity. Overall, these findings highlight a novel potential non-neuronal source of fibrillar -synuclein protein that might arise in gut mucosal cells.

neuroscience↗

bioRxiv2019

Noncanonical scaffolding of Gαi and β-arrestin by G protein-coupled receptors

G-protein-coupled receptors (GPCRs) enable cells to sense and respond appropriately to hormonal and environmental signals, and are a target of ~30% of all FDA-approved medications. Canonically, each GPCR couples to distinct G proteins, such as Gs, Gi, Gq or G12/13, as well as {beta}-arrestins. These transducer proteins translate and integrate extracellular stimuli sensed by GPCRs into intracellular signals through what are broadly considered separable signalling pathways. However, the ability of G proteins to directly interact with {beta}-arrestins to integrate signalling has not previously been appreciated. Here we show a novel interaction between Gi protein family members and {beta}-arrestin. Gi:{beta}-arrestin complexes were formed by all GPCRs tested, regardless of their canonical G protein isoform coupling, and could bind both GPCRs as well as the extracellular signal-regulated kinase (ERK). This novel paradigm of Gi:{beta}-arrestin scaffolds enhances our understanding of GPCR signalling.

cell biology↗