Biology subjects

Swaney, D.

Publications and source records attributed to Swaney, D..

10 recordsLinked to original sources

bioRxiv2026

A de novo designed enzyme for photo-proximity labeling of E3 ligase neighborhoods in live cells

Photocatalytic proximity labeling proteomics (photo-PLP) has emerged as a powerful technology for rapid capture of protein interactomes in situ. Typically, photo-PLP relies on chemical conjugation of the photocatalyst to the target of interest which creates practical challenges for derivatized photocatalyst synthesis and bioconjugation specificity. Integrating the precision of genetically encodable enzymes with the versatility of chemically defined photocatalysts provides a modular approach to further expand the scope of neighborhood mapping. Here, we present EYClamp, a de novo designed proximity labeling enzyme harnessing the off-the-shelf photocatalyst Eosin Y (EY) as a cofactor. Using a domain-swapped dimer architecture, we designed a scaffold that binds EY with high affinity (Kd = 10 nM) and lengthens its triplet excited-state lifetime by 29-fold. EYClamp enables efficient, multi-scale photocatalytic proximity labeling in live cells with aryl-diazirine-, aryl-azide- and phenol-biotin. We genetically fused EYClamp to a panel of six important E3 ligases. Using EYClamp, we identified over 1,500 candidate neighbors for KEAP1, MDM2, ASB7 and STUB1, providing a broad and unbiased view of these important neighborhoods. Critical functional networks were revealed including ASB7 engagement with HP1a/CUL5 complex for heterochromatin remodeling. Our EYClamp provides a genetically encodable "plug-and-play" solution for photo-PLP interactome discovery of the large family of E3 ligases and establishes domain-swapping as a promising strategy for de novo photoenzyme design.

biochemistry↗

bioRxiv2023

The microenvironment dictates glycocalyx construction and immune surveillance

Efforts to identify anti-cancer therapeutics and understand tumor-immune interactions are built with in vitro models that do not match the microenvironmental characteristics of human tissues. Using in vitro models which mimic the physical properties of healthy or cancerous tissues and a physiologically relevant culture medium, we demonstrate that the chemical and physical properties of the microenvironment regulate the composition and topology of the glycocalyx. Remarkably, we find that cancer and age-related changes in the physical properties of the microenvironment are sufficient to adjust immune surveillance via the topology of the glycocalyx, a previously unknown phenomenon observable only with a physiologically relevant culture medium. Key PointsO_LICulture medium dictates cellular mechanoresponse signatures in vitro C_LIO_LIEpithelial glycocalyx construction is mediated by Heat Shock Factor 1 (HSF1) C_LIO_LISialic acid topology dictates Natural Killer cell cytotoxicity C_LIO_LIPhysiological microenvironments reveal distinct glycobiology C_LI

cell biology↗

bioRxiv2023

Parallelized screening of virus accessory genes reveals diverse defense and counter-defense mechanisms

Viruses have been evolving host-modifying factors for billions of years. Genomes of bacterial and archaeal viruses are replete with fast-evolving, uncharacterized accessory genes (AGs), most of which likely antagonize host defenses or other viruses1, 2. Systematic investigation of AGs could uncover a multitude of biological mechanisms involved in virus-host competition, but AG identification in genomic databases remains a challenge. We developed an integrated computational and high-throughput discovery platform to identify AGs in virus genomes and assay their functions in complementary phage infection-dependent and -independent contexts. Our approach showcases how phages interact with the principal layers of antiviral immunity, including cell surface modifications, restriction systems, and abortive infection (Abi) mechanisms, which operate simultaneously in the same host. We discovered multiple Enterobacteriophage AGs associated with counter-defense functions that activate rather than inhibit antiviral immunity in cells, including the surprising finding that anti-restriction AGs elicit programmed cell death (PCD) activity of some restriction-modification (R-M) systems. We propose that counter-defense AGs that trigger PCD create a conundrum for phages whereby keeping the AGs causes PCD but losing them exposes the phage to restriction by bacteria. Strategies employed by viruses to avoid this double jeopardy could be an important factor in virus evolution that remains to be explored.

microbiology↗

bioRxiv2023

HBV rewires liver cancer signaling by altering PP2A complexes

Infection by hepatitis B virus (HBV) increases risk for liver cancer by inducing inflammation, cellular stress and cell death. To elucidate the molecular pathways by which HBV promotes cancer development and progression, we used affinity purification mass spectrometry to comprehensively map a network of 145 physical interactions between HBV and human host proteins in hepatocellular carcinoma (HCC). We find that viral proteins target host factors that are preferentially mutated in non-HBV-associated HCC, implicating cancer pathways whose interaction with HBV plays a role in HCC. Focusing on proteins that directly interact with the HBV oncoprotein X (HBx), we show that HBx remodels the PP2A phosphatase complex, altering its effect on tumor signaling. HBx excludes striatin-family regulatory subunits from PP2A, causing Hippo kinase activation and unmasking a requirement for mTOR complex 2 to maintain expression of the YAP oncoprotein in HCC. Thus, HBV rewires HCC to expose potentially targetable signaling dependencies. SignificancePrecision medicine has revolutionized cancer treatment but remains elusive for HCC. We used proteomics to define HBV/host interactions and integrated them with HCC mutations. The results implicate modifiers of HCC behavior via remodeling of host complexes and illuminate new biological mechanisms in advanced disease for therapeutic investigation.

cancer biology↗

bioRxiv2022

Chlamydia trachomatis effector Dre1 interacts with dynactin to reposition host organelles during infection

Chlamydia trachomatis is an obligate intracellular pathogen that replicates within a specialized membrane-bound compartment, called the inclusion. Chlamydia species express a unique class of effectors, Incs, which are translocated from the bacteria by a Type III secretion system and are inserted into the inclusion membrane where they modulate the host-bacterium interface. C. trachomatis repositions specific host organelles during infection to acquire nutrients and evade host cell surveillance, however the bacterial and host proteins controlling these processes are largely unknown. Here, we identify an interaction between the host dynactin complex and the C. trachomatis Inc CT192 (CTL0444), hereafter named Dre1 for Dynactin Recruiting Effector 1. We show that dynactin is recruited to the inclusion in a Dre1-dependent manner and that loss of Dre1 diminishes the recruitment of specific host organelles, including the centrosome, mitotic spindle, and Golgi apparatus to the inclusion. Inactivation of Dre1 results in decreased C. trachomatis fitness in cell-based assays and in a mouse model of infection. By targeting particular functions of the versatile host dynactin complex, Dre1 facilitates re-arrangement of certain organelles around the growing inclusion. Our work highlights how C. trachomatis employs a single effector to evoke specific, large-scale changes in host cell organization that establish an intracellular replicative niche without globally inhibiting host cellular function.

microbiology↗

bioRxiv2021

Tau interactome mapping reveals dynamic processes in synapses and mitochondria associated with neurodegenerative disease

Tau (MAPT) drives neuronal dysfunction in Alzheimers disease (AD) and other tauopathies. To dissect the underlying mechanisms, we combined an engineered ascorbic acid peroxidase (APEX) approach with quantitative affinity purification mass spectrometry (AP-MS) followed by proximity ligation assay (PLA) to characterize Tau interactomes modified by neuronal activity and mutations that cause frontotemporal dementia (FTD) in human induced pluripotent stem cell (iPSC)-derived neurons. We established activity-dependent interactions of Tau with presynaptic vesicle proteins during Tau secretion and mapped the exact APEX-tau-induced biotinylated tyrosines to the cytosolic domains of the interacting vesicular proteins. We showed that FTD mutations impair bioenergetics and markedly diminished Taus interaction with mitochondria proteins, which were downregulated in AD brains of multiple cohorts and correlated with disease severity. These multi-modal and dynamic Tau interactomes with unprecedented spatiotemporal resolution shed novel insights into Taus role in neuronal function and disease-related processes with potential therapeutic targets to block Tau-mediated pathogenesis.

neuroscience↗

bioRxiv2021

A missense variant effect prediction and annotation resource for SARS-CoV-2

The COVID19 pandemic is a global crisis severely impacting many people across the world. An important part of the response is monitoring viral variants and determining the impact they have on viral properties, such as infectivity, disease severity and interactions with drugs and vaccines. In this work we generate and make available computational variant effect predictions for all possible single amino-acid substitutions to SARS-CoV-2 in order to complement and facilitate experiments and expert analysis. The resulting dataset contains predictions from evolutionary conservation and protein and complex structural models, combined with viral phosphosites, experimental results and variant frequencies. We demonstrate predictions effectiveness by comparing them with expectations from variant frequency and prior experiments. We then identify higher frequency variants with significant predicted effects as well as finding variants measured to impact antibody binding that are least likely to impact other viral functions. A web portal is available at sars.mutfunc.com, where the dataset can be searched and downloaded.

bioinformatics↗

bioRxiv2021

Host-directed therapies against early-lineage SARS-CoV-2 retain efficacy against B.1.1.7 variant

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has resulted in millions of deaths worldwide and massive societal and economic burden. Recently, a new variant of SARS-CoV-2, known as B.1.1.7, was first detected in the United Kingdom and is spreading in several other countries, heightening public health concern and raising questions as to the resulting effectiveness of vaccines and therapeutic interventions. We and others previously identified host-directed therapies with antiviral efficacy against SARS-CoV-2 infection. Less prone to the development of therapy resistance, host-directed drugs represent promising therapeutic options to combat emerging viral variants as host genes possess a lower propensity to mutate compared to viral genes. Here, in the first study of the full-length B.1.1.7 variant virus, we find two host-directed drugs, plitidepsin (aplidin; inhibits translation elongation factor eEF1A) and ralimetinib (inhibits p38 MAP kinase cascade), as well as remdesivir, to possess similar antiviral activity against both the early-lineage SARS-CoV-2 and the B.1.1.7 variant, evaluated in both human gastrointestinal and lung epithelial cell lines. We find that plitidepsin is over an order of magnitude more potent than remdesivir against both viruses. These results highlight the importance of continued development of host-directed therapeutics to combat current and future coronavirus variant outbreaks.

microbiology↗

bioRxiv2020

Bimodal evolution of Src and Abl kinase substrate specificity revealed using mammalian cell extract as substrate pool

The specificity of phosphorylation by protein kinases is essential to the integrity of biological signal transduction. While peptide sequence specificity for individual kinases has been examined previously, here we explore the evolutionary progression that has led to the modern substrate specificity of two non-receptor tyrosine kinases, Abl and Src. To efficiently determine the substrate specificity of modern and reconstructed ancestral kinases, we developed a method using mammalian cell lysate as the substrate pool, thereby representing the naturally occurring substrate proteins. We find that the oldest tyrosine kinase ancestor was a promiscuous enzyme that evolved through a more specific last common ancestor into a specific human Abl. In contrast, the parallel pathway to human Src involved a loss of substrate specificity, leading to general promiscuity. These results add a new facet to our understanding of the evolution of signaling pathways, with both subfunctionalization and neofunctionalization along the evolutionary trajectories.

biochemistry↗

bioRxiv2019

Global proteomic profiling of primary macrophages during M. tuberculosis infection identifies TAX1BP1 as a mediator of autophagy targeting

Macrophages are highly plastic cells that adopt diverse functional capabilities and play critical roles in immunity, cancer, and tissue homeostasis, but how these different cell fates and activities are triggered in response to their environmental cues is not well understood. We used new proteomic tools to identify protein post-translational modifications (PTMs) that control antibacterial responses of macrophages. Here, we report an unbiased and global analysis of the changes in host protein abundance, phosphorylation, and ubiquitylation, during the first 24-hours of Mycobacterium tuberculosis (Mtb) infection of primary macrophages. We discovered 1379 proteins with changes in their phosphorylation state and 591 proteins with changes in their ubiquitylation in response to Mtb infection. We identified pathways regulated by phosphorylation and ubiquitylation that werent reflected by changes in protein abundance, indicating that the activity of these pathways was regulated. These include pathways known to be regulated by ubiquitylation and phosphorylation (e.g. autophagy) as well as pathways that were not known to be regulated during Mtb infection (e.g. nucleocytoplasmic transport and mRNA metabolism). We identified an enrichment in phosphorylation of autophagy receptors (TAX1BP1, p62, optineurin, BNIP3L), several of which were not previously implicated in the host response to Mtb infection. We found that p62 deficiency blocks ubiquitylation and TAX1BP1 deficiency enhances ubiquitylation, suggesting p62 ubiquitylation acts as an amplification loop by promoting downstream adaptor recruitment and serves as a platform for recruitment of ubiquitin. Our results show that TAX1BP1 mediates clearance of ubiquitylated Mtb and targets the bacteria to LC3-positive phagophores. Taken together, our proteomic profiling is likely a valuable resource for initiating mechanistic studies of macrophage biology.

microbiology↗