Biology subjects

Kwon, Y. V.

Publications and source records attributed to Kwon, Y. V..

8 recordsLinked to original sources

bioRxiv2026

Comparison of Techniques for Isolating Small Extracellular Vesicles from Drosophila Larval Hemolymph

Extracellular vesicles (EVs) are membrane-delimited nanoparticles, secreted by virtually all tested cell types to mediate intercellular and interorgan communication by transporting biomolecules, such as proteins, nucleic acids, and lipids, to recipient cells. Many EV isolation techniques have been developed for mammalian EVs and exploit specific EV properties, such as size, density, and solubility. Although Drosophila has emerged as a simple yet robust animal model for studying fundamental EV biology in its native context, it remains unclear whether commonly used EV isolation techniques can be applied to hemolymph (Drosophila blood). In this study, we first provide an in-depth characterization of particles in hemolymph using two complementary particle analysis techniques: dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA). We then evaluate the performance of three commonly used small EV isolation methods--solvent precipitation, ultracentrifugation, and size-exclusion chromatography--for their ability to isolate small EVs from Drosophila larval hemolymph. All three methods can enrich small EVs from hemolymph to varying degrees, but none completely remove circulating proteins and lipoproteins. In particular, size-exclusion chromatography yields the purest small EV fractions, as evidenced by the enrichment of Drosophila orthologs of human small EV markers, including Tetraspanin 42Ee (Tsp42Ee), Tetraspanin 42Ed (Tsp42Ed), Tetraspanin 96F (Tsp96F), and Annexin B11 (AnxB11), although it produces the lowest protein yield. Altogether, our study provides practical guidance on both selecting an appropriate small EV isolation method and rigorously characterizing isolated small EV fractions according to specific research needs. More broadly, the knowledge gained from this study provides a framework for the isolation and characterization of small EVs in other insects, thereby facilitating future EV research across diverse insect species.

cell biology↗

bioRxiv2026

A Modular Platform for Purification of Organelle-associated Mitochondria Reveals Functional Specialization at Organelle Contact Sites

Mitochondria perform diverse metabolic and signaling functions, yet how these activities are spatially organized within the mitochondrial network of cells remains poorly understood. Organelle contact sites are spatially restricted hubs that regulate mitochondrial metabolism, signaling, and dynamics, and are therefore well positioned to influence mitochondrial specialization. Investigation of contact site-associated mitochondrial populations has been hindered by a lack of methods to isolate these subpopulations. Here, we develop Organelle Contact-dependent Affinity Purification (ORCA), a workflow for the isolation and analysis of subpopulations of intact mitochondria and associated proteins defined by their organelle contacts. ORCA revealed distinct proteomes for mitochondria associated with the endoplasmic reticulum, lysosomes, peroxisomes, and the Golgi apparatus, demonstrating that organelle contacts define biochemically specialized mitochondrial populations. Focused analysis of Golgi-associated mitochondria showed enrichment of mitochondrial ribosomes and increased mitochondrial translation, revealing an unexpected role for Golgi-mitochondria contacts in regulating mitochondrial protein homeostasis. ORCA also identified the previously uncharacterized Golgi protein KIAA0930/GMO1 as an evolutionarily conserved regulator of oxidative phosphorylation at Golgi-mitochondria contacts. Together, our findings establish ORCA as a broadly applicable approach for investigating the spatial organization of intracellular organelles and reveal organelle contacts as key determinants of mitochondrial specialization.

cell biology↗

bioRxiv2026

Mitochondrial metabolic remodeling drives innate immune activation in Drosophila hemocytes

Innate immune cells rapidly reprogram their metabolism upon activation, yet the metabolic basis of this flexibility in invertebrate systems remains largely unexplored. Here, we investigate the metabolic landscape of Drosophila larval hemocytes, functional analogs of vertebrate myeloid cells, across developmental stages, genotypes, and immune activation states, by combining metabolic flux measurements with single-cell transcriptomics. Under homeostatic conditions, hemocytes rely predominantly on mitochondrial oxidative phosphorylation for ATP production, with minimal glycolytic contribution. Immune activation, particularly lamellocyte differentiation, drives enhanced mitochondrial respiration and metabolic flexibility, accompanied by structural remodeling of the mitochondrial network. Mechanistically, functional lamellocytes require Drp1-mediated mitochondrial fission and utilize glucose and trehalose as primary carbon sources to sustain mitochondrial respiration, which is essential for effective immune responses. Overall, these findings establish that mitochondrial metabolic reprogramming is a conserved feature of innate immune activation in myeloid-like immune cells and reveal an evolutionarily ancient link between mitochondrial dynamics and immune cell activation, with implications for understanding metabolic regulation of innate immunity in invertebrate models and beyond.

developmental biology↗

bioRxiv2023

Comparative Interactome Analysis of α-arrestin Families in Human and Drosophila

The -arrestins form a large family of evolutionally conserved modulators that control diverse signaling pathways, including both G-protein-coupled receptor-(GPCR-) mediated and non-GPCR mediated pathways, across eukaryotes. However, unlike {beta}-arrestins, only a few -arrestin targets and functions have been characterized. Here, using affinity purification and mass spectrometry, we constructed interactomes for six human and twelve Drosophila -arrestins. The resulting high-confidence interactomes comprised 307 and 467 prey proteins in human and Drosophila, respectively. A comparative analysis of these interactomes predicted not only conserved binding partners, such as motor proteins, proteases, ubiquitin ligases, RNA splicing factors, and GTPase-activating proteins, but also those specific to mammals, such as histone modifiers and the subunits of V-type ATPase. Given the manifestation of the interaction between the human -arrestin, TXNIP, and the histone-modifying enzymes, including HDAC2, we undertook a global analysis of transcription signals and chromatin structures that were affected by TXNIP knockdown. We found that TXNIP activated targets by blocking HDAC2 recruitment to targets, a result that was validated by chromatin immunoprecipitation assays. Additionally, the interactome for an uncharacterized human -arrestin ARRDC5 uncovered multiple components in the V-type ATPase, which plays a key role in bone resorption by osteoclasts. Our study presents conserved and species-specific protein-protein interaction maps for -arrestins, which provide a valuable resource for interrogating their cellular functions for both basic and clinical research.

cell biology↗

bioRxiv2022

The native cell differentiation program aberrantly recapitulated in yki3S/A-induced intestinal hyperplasia drives invasiveness and cachexia-like wasting phenotypes

Many tumors recapitulate the developmental and differentiation program of their tissue of origin, a basis for tumor cell heterogeneity. Although stem-cell-like tumor cells are well-studied, the roles of tumor cells undergoing differentiation in inducing the phenotypes associated with advanced cancers remains to be elucidated. Here, we employ Drosophila genetics to demonstrate that the native differentiation program of intestinal stem cells plays a key role in determining an intestinal tumors capacity to invade and induce various non-tumor-autonomous phenotypes. The differentiation program that generates absorptive cells enterocytes is aberrantly recapitulated in the intestinal tumors generated through activation of the Yap1 ortholog Yorkie. Elimination of tumor cells in the enterocyte lineage allows stem cell-like tumor cells to grow but suppresses invasiveness and reshapes various phenotypes associated with cachexia-like wasting by altering the expression of tumor-derived factors. Our study provides insight into how a native differentiation program determines a tumors capacity to induce the phenotypes associated with advanced cancers and suggests that manipulating the differentiation programs co-opted in tumors might be a way to treat some complications of cancer, including cachexia.

developmental biology↗

bioRxiv2021

The roles of distinct Ca2+ signaling mediated by Piezo and inositol triphosphate receptor (IP3R) in the remodeling of E-cadherin during cell dissemination

Given the role of E-cadherin (E-cad) in holding epithelial cells together, the inverse relationship between E-cad levels and cell invasion has been perceived as a principle underlying the invasiveness of tumor cells. In contrast, our study employing the Drosophila model of cell dissemination demonstrates that E-cad is necessary for the invasiveness of Rasv12-transformed cells in vivo. Drosophila E-cad/{beta}-catenin disassembles at adherens junctions and assembles at invasive protrusions--the actin- and cortactin-rich invadopodia-like protrusions associated with breach of the extracellular matrix (ECM)--during cell dissemination. Loss of E-cad attenuates dissemination of Rasv12-transformed cells by impairing their ability to compromise the ECM. Strikingly, the remodeling of E-cad/{beta}-catenin subcellular distribution is controlled by two discrete intracellular calcium signaling pathways: Ca2+ release from endoplasmic reticulum via the inositol triphosphate receptor (IP3R) disassembles E-cad at adherens junctions while Ca2+ entry via the mechanosensitive channel Piezo assembles E-cad at invasive protrusions. Thus, our study provides molecular insights into the unconventional role of E-cad in cell invasion during cell dissemination in vivo and describes the discrete roles of intracellular calcium signaling in the remodeling of E-cad/{beta}-catenin subcellular localization.

cell biology↗

bioRxiv2021

Wear and Tear of the Intestinal Visceral Musculature by Intrinsic and Extrinsic Factors

The gut visceral musculature plays essential roles in not only moving substances through the lumen but also maintaining the function and physiology of the gut. Although the development of the visceral musculature has been studied in multiple model organisms, how it degenerates is poorly understood. Here, we employ the Drosophila midgut as a model to demonstrate that the visceral musculature is disrupted by intrinsic and extrinsic factors, such as aging, feeding, chemical-induced tissue damage, and oncogenic transformation in the epithelium. Notably, we define four prominent visceral musculature disruption phenotypes, which we refer as sprout, discontinuity, furcation, and crossover of the longitudinal muscle. Given that the occurrence of these phenotypes is increased during aging and under various stresses, we propose that these phenotypes can be used as quantitative readouts of deterioration of the visceral musculature. Intriguingly, administration of a tissue-damaging chemical dextran sulfate sodium (DSS) induced similar visceral musculature disruption phenotypes in zebrafish larvae, indicating that ingestion of a tissue-damaging chemical can disrupt the visceral musculature in a vertebrate as well. Our study provides insights into the deterioration of the gut visceral musculature and lays a groundwork for investigating the underlying mechanisms in Drosophila as well as other animals.

developmental biology↗

bioRxiv2020

Tumors Negate the Action of ImpL2 by Elevating Wingless

Tumors often secrete wasting factors associated with atrophy and degeneration of host tissues. If tumors were affected by the wasting factors, mechanisms allowing tumors to evade the adverse effects of the wasting factors must exist and impairing such mechanisms may attenuate tumors. We used Drosophila midgut tumor models to show that tumors upregulate Wingless (Wg) to oppose the growth-impeding effects caused by the wasting factor, ImpL2 (Insulin-like growth factor binding protein (IGFBP)-related protein). Growth of Yorkie (Yki)-induced tumors is dependent on Wg while either elimination of ImpL2 or elevation of Insulin/IGF signaling in tumors revokes this dependency. Notably, Wg augmentation could be a general mechanism for supporting the growth of tumors with elevated ImpL2 and exploited to attenuate muscle degeneration during wasting. Our study elucidates the mechanism by which tumors negate the action of ImpL2 and implies that targeting the Wnt/Wg pathway might be an efficient treatment strategy for cancers with elevated IGFBPs.

cancer biology↗