Biology subjects

Hodgson, L.

Publications and source records attributed to Hodgson, L..

15 recordsLinked to original sources

bioRxiv2026

A genetically encoded RhoG FRET biosensor reveals spatially compartmentalized RhoG-Rac1 signaling during cell protrusion

RhoG is a member of the Rho-family of small GTPases, and is closely related to the canonical Rac1 GTPase, implicated in membrane trafficking, dorsal ruffling, macropinocytosis, and cell protrusion, but its activity has been difficult to visualize directly in living cells with high spatial and temporal resolution. Here, we developed and validated a genetically encoded, single-chain Forster resonance energy transfer (FRET) biosensor for RhoG based on a C-terminal full-length RhoG and an intramolecular RhoG-binding domain derived from ELMO1. The biosensor showed a robust dynamic range when comparing constitutively active and inactive RhoG mutants, responded appropriately to regulation by RhoGDI, GAPs, and GEFs, and detected growth factor-stimulated RhoG activation in live cells. Imaging in mouse embryonic fibroblasts revealed dynamic RhoG activation at leading-edge protrusions, dorsal ruffles, and forming pinocytic and macropinocytic structures. To define the signaling relationship between RhoG and its closely related family member Rac1, we combined the RhoG biosensor with a near-infrared Rac1 FRET biosensor for simultaneous live-cell imaging. Morphodynamic mapping showed that both RhoG and Rac1 activities were positively coupled to edge protrusion, with strongest correlations near the leading-edge, but their direct coupling varied with distance from the edge, indicating partial spatial decoupling within protrusive regions. Inhibition of Src-family kinases altered RhoG dynamics, strongly suppressed Rac1 coupling to protrusion, and inverted the normal positive correlation between RhoG and Rac1 activities. Signaling microdomain analysis further showed that Src inhibition selectively prolonged Rac1 microdomain lifetimes without significantly affecting RhoG domains. Together, these results establish a new biosensor for direct visualization of RhoG activity and reveal that RhoG and Rac1 are coordinated but spatially and temporally distinct components of protrusion-associated signaling networks, with Src-family kinases playing a central role in maintaining their normal coupling.

cell biology↗

bioRxiv2026

Mapping Alzheimer's neuropathology signatures to the whole brain transcriptome using machine learning data fusion

In Alzheimer's disease (AD), misfolded proteins emerge across the entire brain in structured, yet not rigid, spatiotemporal patterns. Yet, a systematic bias of single-cell genomics toward sampling mostly cortical tissue limits our understanding of the whole-brain transcriptomic vulnerability to AD. Here, we develop a machine learning method to extrapolate local AD neuropathology signatures to the whole brain. By analyzing gene expression profiles of over two million cortical cells from 427 humans spanning the AD-pathology spectrum, we derive transcriptomic estimators of AD neuropathology. After extensive validations on datasets with known ground truth, we apply this framework to three million cells from 108 brain regions in the Siletti whole human brain atlas and derive an anticipated brain map of transcriptomic signatures indexing AD neuropathology. This interrogation of regions spanning the cortical, subcortical, and brainstem structures uncovers transcriptomic signatures associated with hyperphosphorylated tau in the medulla oblongata, dorsal raphe nucleus, and the tuberal and mammillary regions of the hypothalamus. At the cellular level, assessments of these signatures across 31 cell populations identify VGLUT1/2 expressing neurons, astrocytes, and microglia as key neuropathology-resembling populations. Within the hippocampus, pathology signatures surface in the rostral cornu ammonis (CA) subfields, particularly in the CA1 pyramidal neurons and dentate granule cells. {beta}-amyloid-like signatures localize to the neocortex with laminar selectivity--most prominently in upper layer somatostatin+ intratelencephalic neurons (L2-L3), but also in deep layer intratelencephalic and corticothalamic neurons (L5-L6). Neocortical astrocytes and microglia exhibiting disease associated signatures similarly demonstrate a unique laminar preference. Together, this study provides the first whole human brain map of AD pathology-associated transcriptomic signals, and exposes cell type, region, and cortex layer specific vulnerabilities.

neuroscience↗

bioRxiv2026

ARHGAP20 organizes spatial Rap1-RhoA signaling coordination controlling adhesion dynamics during migration

Cell migration requires the precise coordination of signaling pathways that regulate cytoskeletal dynamics and adhesion turnover. Rho GTPase-activating proteins (RhoGAPs) play critical roles in shaping these processes by controlling the spatial and temporal activity of small GTPases. ARHGAP20 is a RhoA-specific GAP, a downstream target of the Ras-related GTPase Rap1, and has been implicated in cancer cell motility, yet its functional role in coordinating migration-associated signaling remains poorly understood. Here, we investigated the role of ARHGAP20 in cell migration and its impact on the coordination between adhesion- and contractility-associated signaling pathways regulated by Rap1A and RhoA respectively. Using loss-of-function approaches in MTLn3 cells, we show that depletion of ARHGAP20 impairs both directed and random migration, leading to reduced cell velocity and displacement, and increased cell adhesion. To explore the underlying signaling mechanisms, we developed a genetically encoded FRET biosensor to monitor Rap1A activity and combined it with a near-infrared RhoA biosensor to simultaneously analyze their spatiotemporal dynamics in living cells. We found that Rap1A and RhoA activities are negatively coordinated during leading-edge dynamics and that ARHGAP20 depletion enhances this local anticorrelation. To further define where ARHGAP20 regulates Rap1A-RhoA signaling, we applied a microdomain-based analytical framework to quantify local signaling clusters. This analysis revealed that ARHGAP20 selectively modulates Rap1A-RhoA coordination outside focal adhesion regions, while leaving signaling correlations and overlap within focal adhesions unchanged. Subcellular localization analyses further reveal that ARHGAP20 is largely excluded from focal adhesions but associates with microtubules, the endoplasmic reticulum, the Golgi apparatus, and multiple Rab-positive vesicular compartments, supporting a trafficking-dependent mechanism for its spatial targeting. Together, our results identify ARHGAP20 as a regulator of cell migration that modulates the coordination between Rap1A and RhoA signaling through intracellular vesicular trafficking, highlighting the GAPs role in organizing the spatial coupling between signaling pathways in adhesion-associated regions required for efficient cell migration.

cell biology↗

bioRxiv2026

Distinct roles for TANGO1S domains in maintaining ER-Golgi architecture

The endoplasmic reticulum (ER)-Golgi interface is a dynamic trafficking hub maintained in part by TANGO1, a scaffolding protein that coordinates proteins and membranes at ER exit sites (ERES). TANGO1 has two isoforms: TANGO1L, which has a lumenal SH3 domain, and TANGO1S, which lacks this domain but retains the transmembrane and cytoplasmic coiled coil (CC), TEER, and PRD domains common to both forms. We showed previously that loss of both isoforms disrupts ER - Golgi organization more severely than TANGO1L loss alone, indicating TANGO1S is functional and can compensate. Here we dissect the role of each TANGO1 cytoplasmic domain in maintaining secretory pathway organisation by expressing TANGO1S domain-deletion mutants in TANGO1L-/S- knockout cells. We show that TANGO1 loss causes cis-Golgi vesiculation that cannot be rescued by TANGO1S. TANGO1S re-expression also failed to rescue COPII and Sec16 recruitment in this cell line. Meanwhile, the TEER domain is essential for the organisation of the ER, and the TEER, CC2 and PRD domain are required for a defined ERGIC. This study represents an advance towards a domain-level resolution of TANGO1S function.

cell biology↗

bioRxiv2026

Sensory neurons inhibit invadopodia and metastasis via direct CGRP-RAMP1-cAMP signaling to cancer cells

Breast cancer is globally the most common cancer among women. Although the five-year survival rate exceeds 80% for patients with localized disease, it drops to approximately 30% once metastasis occurs, underscoring the urgent need to define mechanisms that drive metastatic progression. Breast is a highly innervated organ and most of its innervation is sensory. However, whether sensory neurons can directly impact breast cancer cells remains an understudied topic. Here, we show that mammary tumors have increased CGRP sensory innervation. Using our novel microfluidic Device for Cancer cell-Axon Interaction Testing (DACIT), we demonstrate that the presence of axons strongly inhibits ECM-degrading ability of cancer cells. The sensory neuron secretome suppresses assembly and function of invadopodia, which are cancer cell protrusions controlling ECM degradation, and essential for intravasation and metastasis. We identify calcitonin gene-related peptide (CGRP) as the key component of the sensory neuron secretome responsible for the inhibitory effect. CGRP signaling occurs through the CRLR/RAMP1 receptor complex expressed by breast cancer cells, inducing a rapid increase in intracellular cAMP levels in breast cancer cells, followed by an increase in RhoC activity and suppression of invadopodia and ECM degradation. Loss of RAMP1 function enhances 3D spheroid invasion, cancer cell motility in vivo and significantly increases the number and the size of lung metastatic foci. Consistently, in silico analyses of both mouse and human RNASeq data point to a link between increasingly invasive subtypes with a gradual decrease in expression of RAMP1 and CRLR. To validate in silico findings, we compare RAMP1 expression in the patient breast tumors with adjacent normal tissues, confirming the invasive breast tumors have reduced levels of RAMP1. Together, our findings identify a protective role for the paracrine CGRP signaling in limiting breast cancer invasion and metastasis. We also demonstrate how cancer cells circumvent CGRP inhibition by suppressing RAMP1 expression, highlighting CGRP-RAMP1-cAMP axis as a potential therapeutic target in breast cancer.

cancer biology↗

bioRxiv2026

Orphan GPR84 facilitates uropod de-adhesion to terminate leukocyte diapedesis during inflammation

Leukocyte migration through venular walls is an essential component of effective immunity. While the key molecular players driving the initial steps of this response are known, the terminating signals remain unclear. Here, we have identified a conserved role for GPR84 family GPCRs in successful completion of the final stages of leukocyte extravasation through acutely inflamed vessels. The integration of high resolution intravital imaging with cell-specific genetics revealed that genetic deficiency of GPR84 orthologues in mice and Drosophila, results in defective detachment of transmigrating immune cells from vessel walls. Mechanistically, transcriptomics revealed GPR84-deficient neutrophils exhibit defective actin cytoskeletal regulation and cellular adhesion/de-adhesion. Consistent with this, our fly-murine pipeline shows that GPR84 supports localized and dynamic Rho activation to enable detachment of the immune cell uropod from vessel exit sites. Moreover, pharmacological blockade of GPR84 signaling dampened immune cell migration in multiple murine acute inflammatory settings. Collectively, our findings present GPR84 as a novel physiological regulator of immune cell extravasation that is amenable to therapeutic targeting for modulating leukocyte infiltration into inflamed tissues. SummaryHere we identify the GPR84 family of GPCRs as key regulators of effective immune cell extravasation in vivo. Mechanistically, through integrating genetically tractable Drosophila and murine in vivo models, we show how leukocyte GPR84 supports dynamic Rho-dependent detachment of stretched uropods as these cells exit vessels.

immunology↗

bioRxiv2026

A new single chain, genetically encoded biosensor for RhoB GTPase based on FRET, useful for live-cell imaging

RhoB is an atypical Rho GTPase whose function is tightly linked to its subcellular localization and membrane trafficking, reflecting its unique post-translational modifications and association with endosomal membranes in addition to the plasma membrane. Despite its implication in membrane trafficking and cytoskeletal regulation, tools to directly monitor RhoB activity in space and time have been lacking. Here, we describe the development and validation of a single-chain, genetically encoded Forster resonance energy transfer (FRET) biosensor that enables direct visualization of RhoB activity in living cells while preserving its native membrane-targeting determinants. The biosensor exhibits a large dynamic range and resolves spatially heterogeneous RhoB activity during leading-edge protrusion - retraction cycles in migrating mouse embryonic fibroblasts. To demonstrate the utility of this tool, we performed multiplex live-cell imaging with a previously developed near-infrared FRET biosensor for the exocytic Rho GTPase TC10. Quantitative morphodynamic and cross-correlation analyses reveal coordinated yet antagonistic spatiotemporal patterns of RhoB and TC10 activities at the leading edge and show that perturbation of TC10 regulation reorganizes their spatial coupling. Together, this work introduces a robust biosensor for RhoB and establishes a multiplex imaging framework to study the coordination of trafficking and signaling during cell migration.

cell biology↗

bioRxiv2025

Intercellular mitochondrial transfer and transmitophagy in response to protein import dysfunction

Mitochondrial protein import is critical for organelle biogenesis and maintenance, essential processes for cellular homeostasis. Import dysfunction compromises cellular energy supplies which is damaging to cells, particularly those with high energetic demands like neurons. Previously, we have shown that import failure is rescued by intercellular mitochondrial transfer via tunnelling nanotubes (TNTs) however, the fate of the transferred mitochondria and the mechanistic basis for rescue was unresolved. Here, we show that bi-directional mitochondrial trafficking between cells harbouring import-defective and import-competent mitochondria has distinct regulation and consequences. Transferred import-defective mitochondria are highly fragmented and destined for canonical lysosomal degradation. In contrast, ROS-producing mitochondria at the periphery of cells with import-competent mitochondria are transferred into neighbouring cells undergoing import failure; these new arrivals then accumulate within previously uncharacterised mitochondrial degradation bodies (MBDs). We speculate that the co-operation of these distinct examples of TNT- mediated conventional and non-canonical transmitophagy instigate mitochondrial regeneration, and thereby rescue.

cell biology↗

bioRxiv2025

Cell type transcriptomics reveal shared genetic mechanisms in Alzheimer's and Parkinson's disease

Historically, Alzheimers disease (AD) and Parkinsons disease (PD) have been investigated as two distinct disorders of the brain. However, a few similarities in neuropathology and clinical symptoms have been documented over the years. Traditional single gene-centric genetic studies, including GWAS and differential gene expression analyses, have struggled to unravel the molecular links between AD and PD. To address this, we tailor a pattern-learning framework to analyze synchronous gene co-expression at sub-cell-type resolution. Utilizing recently published single-nucleus AD (70,634 nuclei) and PD (340,902 nuclei) datasets from postmortem human brains, we systematically extract and juxtapose disease-critical gene modules. Our findings reveal extensive molecular similarities between AD and PD gene cliques. In neurons, disrupted cytoskeletal dynamics and mitochondrial stress highlight convergence in key processes; glial modules share roles in T-cell activation, myelin synthesis, and synapse pruning. This multi-module sub-cell-type approach offers insights into the molecular basis of shared neuropathology in AD and PD.

neuroscience↗

bioRxiv2025

Swirling motion of breast cancer cells radially aligns collagen fibers to enable collective invasion

In breast cancer (BC), radial alignment of collagen fibers at the tumor-matrix interface facilitates collective invasion of cancer cells into the surrounding stromal matrix, a critical step toward metastasis. Collagen remodeling is driven by proteases and cellular forces, mediated by matrix mechanical plasticity, or irreversible matrix deformation in response to force. However, the specific mechanisms causing collagen radial alignment remain unclear. Here, we study collective invasion of BC tumor spheroids in collagen-rich matrices. Increasing plasticity to BC-relevant ranges facilitates invasion, with increasing stiffness potentiating a transition from single cell to collective invasion. At enhanced plasticity, cells radially align collagen at the tumor-matrix interface prior to invasion. Surprisingly, cells migrate tangentially to the tumor-matrix interface in a swirling-like motion, perpendicular to the direction of alignment. Mechanistically, swirling generates local shear stresses, leading to distally propagating contractile radial stresses due to negative normal stress, an underappreciated property of collagen-rich matrices. These contractile stresses align collagen fibers radially, facilitating collective invasion. The basement membrane (BM), which separates epithelia from stroma in healthy tissues, acts as a mechanical insulator by preventing swirling cells from aligning collagen. Thus, after breaching the BM, swirling of BC cells at the tumor-stroma interface radially aligns collagen to facilitate invasion.

biophysics↗

bioRxiv2023

Self-assembly of nanofilaments in cyanobacteria for protein co-localization

Cyanobacteria offer great potential as alternative biotechnological hosts due to their photoautotrophic capacities. However, in comparison to established heterotrophic hosts, several key aspects, such as product titers, are still lagging behind. Nanobiotechnology is an emerging field with great potential to improve existing hosts but, so far, it has barely been explored in microbial photosynthetic systems. Here, we report the establishment of large proteinaceous nanofilaments in the unicellular model cyanobacterium Synechocystis sp. PCC 6803 and the fast-growing cyanobacterial strain Synechococcus elongatus UTEX 2973. Transmission electron microscopy and electron tomography demonstrated that overexpression of a modified bacterial microcompartment shell protein, PduA*, led to the generation of bundles of longitudinally aligned nanofilaments in S. elongatus UTEX 2973 and shorter filamentous structures in Synechocystis sp. PCC 6803. Comparative proteomics showed that PduA* was at least 50 times more abundant than the second most abundant protein in the cell and that nanofilament assembly only had a minor impact on cellular metabolism. Finally, we targeted the fluorescent reporter mCitrine to the nanofilaments using an encapsulation peptide that natively interacts with PduA. To our knowledge, this is the first study to apply bacterial microcompartment based nanotechnology in cyanobacteria. The establishment of nanofilaments in cyanobacterial cells is an important step towards cellular organization of heterologous pathways and the establishment of cyanobacteria as next generation hosts.

synthetic biology↗

bioRxiv2022

Collective invasion of the basement membrane in breast cancer driven by forces from cell volume expansion and local contractility

Breast cancer becomes invasive when carcinoma cells collectively invade through the basement membrane (BM), a nanoporous layer of matrix that physically separates the primary tumor from the stroma, in a first step towards metastasis. Single cells can invade through nanoporous three-dimensional (3D) matrices via protease-mediated degradation or, when the matrix exhibits sufficient mechanical plasticity, force-mediated widening of pores. However, how cells invade collectively through physiological BM layers in cancer remains unclear. Here, we developed a 3D in vitro model of collective invasion of the BM during breast cancer. We show that cells utilize both proteases and forces to breach the BM. Forces are generated from a combination of global cell volume expansion that stretch the BM with local contractile forces that act in the plane of the BM to breach it, allowing invasion. These results uncover a mechanism by which cells collectively interact to overcome a critical barrier to metastasis.

cancer biology↗

bioRxiv2022

The Free Fatty Acid-Binding Pocket is a Conserved Hallmark in Pathogenic β-Coronavirus Spike Proteins from SARS-CoV to Omicron

As COVID-19 persists, severe acquired respiratory syndrome coronavirus-2 (SARS-CoV-2) Variants of Concern (VOCs) emerge, accumulating spike (S) glycoprotein mutations. S receptor-binding domain (RBD) comprises a free fatty acid (FFA)-binding pocket. FFA-binding stabilizes a locked S conformation, interfering with virus infectivity. We provide evidence that the pocket is conserved in pathogenic {beta}-coronaviruses ({beta}-CoVs) infecting humans. SARS-CoV, MERS-CoV, SARS-CoV-2 and VOCs bind the essential FFA linoleic acid (LA), while binding is abolished by one mutation in common cold-causing HCoV-HKU1. In the SARS-CoV S structure, LA stabilizes the locked conformation while the open, infectious conformation is LA-free. Electron tomography of SARS-CoV-2 infected cells reveals that LA-treatment inhibits viral replication, resulting in fewer, deformed virions. Our results establish FFA-binding as a hallmark of pathogenic {beta}-CoV infection and replication, highlighting potential antiviral strategies. One-Sentence SummaryFree fatty acid-binding is conserved in pathogenic {beta}-coronavirus S proteins and suppresses viral infection and replication.

biochemistry↗

bioRxiv2022

ESCPE-1 Mediates Retrograde Endosomal Sorting of the SARS-CoV-2 Host Factor Neuropilin-1

Endosomal sorting maintains cellular homeostasis by recycling transmembrane proteins and associated proteins and lipids (termed cargoes) from the endosomal network to multiple subcellular destinations, including retrograde traffic to the trans-Golgi network (TGN). Viral and bacterial pathogens subvert retrograde trafficking machinery to facilitate infectivity. Here, we develop a proteomic screen to identify novel retrograde cargo proteins of the Endosomal SNX-BAR Sorting Complex Promoting Exit-1 (ESCPE-1). Using this methodology, we identify Neuropilin-1 (NRP1), a recently characterised host factor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, as a cargo directly bound and trafficked by ESCPE-1. ESCPE-1 mediates retrograde trafficking of engineered nanoparticles functionalised with the NRP1-interacting peptide of the SARS-CoV-2 Spike protein. ESCPE-1 sorting of NRP1 may therefore play a role in the intracellular membrane trafficking of NRP1-interacting viruses such as SARS-CoV-2.

cell biology↗

bioRxiv2020

TC10 regulates breast cancer invasion and metastasis by controlling membrane type-1 matrix metalloproteinase at invadopodia

During breast cancer metastasis, cancer cell invasion is driven by actin-rich protrusions called invadopodia, which mediate the extracellular matrix degradation required for the success of the invasive cascade. In this study, we demonstrated that TC10, a member of a Cdc42 subfamily of p21 small GTPases, regulates the membrane type 1 matrix metalloproteinase (MT1-MMP)-driven extracellular matrix degradation at invadopodia. We show that TC10 is required for the plasma membrane surface exposure of MT1-MMP at invadopodia. By utilizing our new Forster resonance energy transfer (FRET) biosensor, we demonstrated the p190RhoGAP-dependent regulation of spatiotemporal TC10 activity at invadopodia. We identified a pathway that regulates TC10 activity and function at invadopodia through the activation of p190RhoGAP and the downstream interacting effector Exo70 at the invadopodia sites. Our findings reveal the role of a previously unknown regulator of vesicular fusion at invadopodia, TC10, on the invasive potential of breast cancer cells during invasion and metastasis.

cell biology↗