RESUMEN
Left unchecked, plant-parasitic nematodes have the potential to devastate crops globally. Highly effective but non-selective nematicides are justifiably being phased-out, leaving farmers with limited options for managing nematode infestation. Here, we report our discovery of a 1,3,4-oxadiazole thioether scaffold called Cyprocide that selectively kills nematodes including diverse species of plant-parasitic nematodes. Cyprocide is bioactivated into a lethal reactive electrophilic metabolite by specific nematode cytochrome P450 enzymes. Cyprocide fails to kill organisms beyond nematodes, suggesting that the targeted lethality of this pro-nematicide derives from P450 substrate selectivity. Our findings demonstrate that Cyprocide is a selective nematicidal scaffold with broad-spectrum activity that holds the potential to help safeguard our global food supply.
Asunto(s)
Antinematodos , Sistema Enzimático del Citocromo P-450 , Nematodos , Animales , Sistema Enzimático del Citocromo P-450/metabolismo , Nematodos/efectos de los fármacos , Antinematodos/farmacología , Sulfuros/farmacología , Sulfuros/químicaRESUMEN
Soil-transmitted helminths (STHs) are major pathogens infecting over a billion people. There are few classes of anthelmintics and there is an urgent need for new drugs. Many STHs use an unusual form of anaerobic metabolism to survive the hypoxic conditions of the host gut. This requires rhodoquinone (RQ), a quinone electron carrier. RQ is not made or used by vertebrate hosts making it an excellent therapeutic target. Here we screen 480 structural families of natural products to find compounds that kill Caenorhabditis elegans specifically when they require RQ-dependent metabolism. We identify several classes of compounds including a family of species-selective inhibitors of mitochondrial respiratory complex I. These identified complex I inhibitors have a benzimidazole core and we determine key structural requirements for activity by screening 1,280 related compounds. Finally, we show several of these compounds kill adult STHs. We suggest these species-selective complex I inhibitors are potential anthelmintics.
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Antihelmínticos , Caenorhabditis elegans , Complejo I de Transporte de Electrón , Ubiquinona/análogos & derivados , Animales , Antihelmínticos/farmacología , Antihelmínticos/química , Complejo I de Transporte de Electrón/antagonistas & inhibidores , Complejo I de Transporte de Electrón/metabolismo , Caenorhabditis elegans/metabolismo , Bencimidazoles/farmacología , Bencimidazoles/química , Especificidad de la Especie , Quinonas/química , Quinonas/farmacología , Quinonas/metabolismo , Productos Biológicos/farmacología , Productos Biológicos/químicaRESUMEN
Ferroptosis is a form of regulated cell death with roles in degenerative diseases and cancer. Excessive iron-catalyzed peroxidation of membrane phospholipids, especially those containing the polyunsaturated fatty acid arachidonic acid (AA), is central in driving ferroptosis. Here, we reveal that an understudied Golgi-resident scaffold protein, MMD, promotes susceptibility to ferroptosis in ovarian and renal carcinoma cells in an ACSL4- and MBOAT7-dependent manner. Mechanistically, MMD physically interacts with both ACSL4 and MBOAT7, two enzymes that catalyze sequential steps to incorporate AA in phosphatidylinositol (PI) lipids. Thus, MMD increases the flux of AA into PI, resulting in heightened cellular levels of AA-PI and other AA-containing phospholipid species. This molecular mechanism points to a pro-ferroptotic role for MBOAT7 and AA-PI, with potential therapeutic implications, and reveals that MMD is an important regulator of cellular lipid metabolism.
Asunto(s)
Ferroptosis , Fosfatidilinositoles , Línea Celular , Ácidos Grasos Insaturados , Fosfatidilinositoles/metabolismo , Fosfolípidos/metabolismo , HumanosRESUMEN
Niemann-Pick type C (NP-C) disease is a rare lysosomal storage disease caused by mutations in NPC1 (95% cases) or NPC2 (5% cases). These proteins function together in cholesterol egress from the lysosome, whereby upon mutation, cholesterol and other lipids accumulate causing major pathologies. However, it is not fully understood how cholesterol is transported from NPC1 residing at the lysosomal membrane to the endoplasmic reticulum (ER) and plasma membrane. The yeast ortholog of NPC1, Niemann-Pick type C-related protein-1 (Ncr1), functions similarly to NPC1; when transfected into a mammalian cell lacking NPC1, Ncr1 rescues the diagnostic hallmarks of cholesterol and sphingolipid accumulation. Here, we aimed to identify and characterize protein-protein interactions (PPIs) with the yeast Ncr1 protein. A genome-wide split-ubiquitin membrane yeast two-hybrid (MYTH) protein interaction screen identified 11 ER membrane-localized, full-length proteins interacting with Ncr1 at the lysosomal/vacuolar membrane. These highlight the importance of ER-vacuole membrane interface and include PPIs with the Cyb5/Cbr1 electron transfer system, the ceramide synthase complex, and the Sec61/Sbh1 protein translocation complex. These PPIs were not detected in a sterol auxotrophy condition and thus depend on normal sterol metabolism. To provide biological context for the Ncr1-Cyb5 PPI, a yeast strain lacking this PPI (via gene deletions) exhibited altered levels of sterols and sphingolipids including increased levels of glucosylceramide that mimic NP-C disease. Overall, the results herein provide new physical and genetic interaction models to further use the yeast model of NP-C disease to better understand human NP-C disease.
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Enfermedad de Niemann-Pick Tipo C , Saccharomyces cerevisiae , Animales , Humanos , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Enfermedad de Niemann-Pick Tipo C/tratamiento farmacológico , Enfermedad de Niemann-Pick Tipo C/genética , Enfermedad de Niemann-Pick Tipo C/metabolismo , Receptor 1 Gatillante de la Citotoxidad Natural/metabolismo , Proteínas/genética , Colesterol , Esteroles/metabolismo , MamíferosRESUMEN
Parasitic nematodes are a major threat to global food security, particularly as the world amasses 10 billion people amid limited arable land1-4. Most traditional nematicides have been banned owing to poor nematode selectivity, leaving farmers with inadequate means of pest control4-12. Here we use the model nematode Caenorhabditis elegans to identify a family of selective imidazothiazole nematicides, called selectivins, that undergo cytochrome-p450-mediated bioactivation in nematodes. At low parts-per-million concentrations, selectivins perform comparably well with commercial nematicides to control root infection by Meloidogyne incognita, a highly destructive plant-parasitic nematode. Tests against numerous phylogenetically diverse non-target systems demonstrate that selectivins are more nematode-selective than most marketed nematicides. Selectivins are first-in-class bioactivated nematode controls that provide efficacy and nematode selectivity.
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Antinematodos , Tylenchoidea , Animales , Humanos , Antinematodos/química , Antinematodos/metabolismo , Antinematodos/farmacología , Caenorhabditis elegans/efectos de los fármacos , Caenorhabditis elegans/metabolismo , Tylenchoidea/efectos de los fármacos , Tylenchoidea/metabolismo , Tiazoles/química , Tiazoles/metabolismo , Tiazoles/farmacología , Sistema Enzimático del Citocromo P-450/efectos de los fármacos , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/parasitología , Enfermedades de las Plantas , Especificidad de la Especie , Especificidad por SustratoRESUMEN
SARS-CoV-2 virus spike (S) protein is an envelope protein responsible for binding to the ACE2 receptor, driving subsequent entry into host cells. The existence of multiple disulfide bonds in the S protein makes it potentially susceptible to reductive cleavage. Using a tri-part split luciferase-based binding assay, we evaluated the impacts of chemical reduction on S proteins from different virus variants and found that those from the Omicron family are highly vulnerable to reduction. Through manipulation of different Omicron mutations, we found that alterations in the receptor binding module (RBM) are the major determinants of this vulnerability. Specifically we discovered that Omicron mutations facilitate the cleavage of C480-C488 and C379-C432 disulfides, which consequently impairs binding activity and protein stability. The vulnerability of Omicron S proteins suggests a mechanism that can be harnessed to treat specific SARS-CoV-2 strains.
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Glicoproteína de la Espiga del Coronavirus , Humanos , Bioensayo , Mutación , Unión Proteica , SARS-CoV-2/genética , Glicoproteína de la Espiga del Coronavirus/química , Glicoproteína de la Espiga del Coronavirus/genética , Oxidación-Reducción , Estabilidad ProteicaRESUMEN
Met is an oncogene aberrantly activated in multiple cancers. Therefore, to better understand Met biology and its role in disease we applied the Mammalian Membrane Two-Hybrid (MaMTH) to generate a targeted interactome map of its interactions with human SH2/PTB-domain-containing proteins. We identified thirty interaction partners, including sixteen that were previously unreported. Non-small cell lung cancer (NSCLC)-focused functional characterization of a Met-interacting protein, BLNK, revealed that BLNK is a positive regulator of Met signaling, and modulates localization, including ligand-dependent trafficking of Met in NSCLC cell lines. Furthermore, the interaction between Met and GRB2 is increased in the presence of BLNK, and the constitutive interaction between BLNK and GRB2 is increased in the presence of active Met. Tumor phenotypical assays uncovered roles for BLNK in anchorage-independent growth and chemotaxis of NSCLC cell lines. Cumulatively, this study provides a Met-interactome and delineates a role for BLNK in regulating Met biology in NSCLC context.
RESUMEN
Nematode parasites of humans, livestock and crops dramatically impact human health and welfare. Alarmingly, parasitic nematodes of animals have rapidly evolved resistance to anthelmintic drugs, and traditional nematicides that protect crops are facing increasing restrictions because of poor phylogenetic selectivity. Here, we exploit multiple motor outputs of the model nematode C. elegans towards nematicide discovery. This work yielded multiple compounds that selectively kill and/or immobilize diverse nematode parasites. We focus on one compound that induces violent convulsions and paralysis that we call nementin. We find that nementin stimulates neuronal dense core vesicle release, which in turn enhances cholinergic signaling. Consequently, nementin synergistically enhances the potency of widely-used non-selective acetylcholinesterase (AChE) inhibitors, but in a nematode-selective manner. Nementin therefore has the potential to reduce the environmental impact of toxic AChE inhibitors that are used to control nematode infections and infestations.
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Caenorhabditis elegans , Nematodos , Acetilcolinesterasa , Animales , Antinematodos/farmacología , Humanos , Neurotransmisores , FilogeniaRESUMEN
The COVID-19 pandemic triggered the development of numerous diagnostic tools to monitor infection and to determine immune response. Although assays to measure binding antibodies against SARS-CoV-2 are widely available, more specific tests measuring neutralization activities of antibodies are immediately needed to quantify the extent and duration of protection that results from infection or vaccination. We previously developed a 'Serological Assay based on a Tri-part split-NanoLuc® (SATiN)' to detect antibodies that bind to the spike (S) protein of SARS-CoV-2. Here, we expand on our previous work and describe a reconfigured version of the SATiN assay, called Neutralization SATiN (Neu-SATiN), which measures neutralization activity of antibodies directly from convalescent or vaccinated sera. The results obtained with our assay and other neutralization assays are comparable but with significantly shorter preparation and run time for Neu-SATiN. As the assay is modular, we further demonstrate that Neu-SATiN enables rapid assessment of the effectiveness of vaccines and level of protection against existing SARS-CoV-2 variants of concern and can therefore be readily adapted for emerging variants.
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COVID-19 , SARS-CoV-2 , Anticuerpos Antivirales , Humanos , Luciferasas , Glicoproteínas de Membrana/metabolismo , Pruebas de Neutralización , Pandemias , Glicoproteína de la Espiga del Coronavirus , Proteínas del Envoltorio ViralRESUMEN
Receptor tyrosine kinases (RTKs) are recognized as targets of precision medicine in human cancer upon their gene amplification or constitutive activation, resulting in increased downstream signal complexity including heterotypic crosstalk with other RTKs. The Met RTK exhibits such reciprocal crosstalk with several members of the human EGFR (HER) family of RTKs when amplified in cancer cells. We show that Met signaling converges on HER3-tyrosine phosphorylation across a panel of seven MET-amplified cancer cell lines and that HER3 is required for cancer cell expansion and oncogenic capacity in vitro and in vivo. Gene expression analysis of HER3-depleted cells identified MPZL3, encoding a single-pass transmembrane protein, as HER3-dependent effector in multiple MET-amplified cancer cell lines. MPZL3 interacts with HER3 and MPZL3 loss phenocopies HER3 loss in MET-amplified cells, while MPZL3 overexpression can partially rescue proliferation upon HER3 depletion. Together, these data support an oncogenic role for a HER3-MPZL3 axis in MET-amplified cancers.
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Proteínas de la Membrana/metabolismo , Proteínas Proto-Oncogénicas c-met/metabolismo , Receptor ErbB-3/metabolismo , Animales , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Línea Celular Tumoral , Proliferación Celular , Regulación Neoplásica de la Expresión Génica , Humanos , Proteínas de la Membrana/antagonistas & inhibidores , Proteínas de la Membrana/genética , Ratones , Ratones Endogámicos NOD , Inestabilidad de Microsatélites , Fosforilación , Isoformas de Proteínas/antagonistas & inhibidores , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Proteínas Proto-Oncogénicas c-met/genética , Interferencia de ARN , ARN Interferente Pequeño/metabolismo , Receptor ErbB-2/genética , Receptor ErbB-2/metabolismo , Receptor ErbB-3/antagonistas & inhibidores , Receptor ErbB-3/genética , Transducción de Señal/genética , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/patología , Trasplante HeterólogoRESUMEN
Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) is a chloride and bicarbonate channel in secretory epithelia with a critical role in maintaining fluid homeostasis. Mutations in CFTR are associated with Cystic Fibrosis (CF), the most common lethal autosomal recessive disorder in Caucasians. While remarkable treatment advances have been made recently in the form of modulator drugs directly rescuing CFTR dysfunction, there is still considerable scope for improvement of therapeutic effectiveness. Here, we report the application of a high-throughput screening variant of the Mammalian Membrane Two-Hybrid (MaMTH-HTS) to map the protein-protein interactions of wild-type (wt) and mutant CFTR (F508del), in an effort to better understand CF cellular effects and identify new drug targets for patient-specific treatments. Combined with functional validation in multiple disease models, we have uncovered candidate proteins with potential roles in CFTR function/CF pathophysiology, including Fibrinogen Like 2 (FGL2), which we demonstrate in patient-derived intestinal organoids has a significant effect on CFTR functional expression.
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Regulador de Conductancia de Transmembrana de Fibrosis Quística , Fibrosis Quística , Animales , Membrana Celular/metabolismo , Fibrosis Quística/tratamiento farmacológico , Fibrosis Quística/genética , Fibrosis Quística/metabolismo , Regulador de Conductancia de Transmembrana de Fibrosis Quística/genética , Regulador de Conductancia de Transmembrana de Fibrosis Quística/metabolismo , Fibrinógeno/genética , Fibrinógeno/metabolismo , Fibrinógeno/farmacología , Ensayos Analíticos de Alto Rendimiento , Humanos , Mamíferos , MutaciónRESUMEN
KRAS is one of the most frequently mutated oncogenes in human cancers. Despite nearly 40 years of research, KRAS remains largely undruggable, in part due to an incomplete understanding of its biology. Recently, KRAS dimerization was discovered to play an important role in its signalling function. The KRAS D154Q mutant was described as a dimer-deficient variant that can be used to study the effect of dimerization in KRAS oncogenicity. However, we show here that KRAS D154Q homo- and heterodimerized with KRAS WT using three separate protein-protein interaction assays, and that oncogenic KRAS dimerization was not negatively impacted by the presence of a secondary D154Q mutation. In conclusion, we advise caution in using this variant to study the purpose of dimerization in KRAS oncogenic behaviour.
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Mutación , Proteínas Proto-Oncogénicas p21(ras)/química , Proteínas Proto-Oncogénicas p21(ras)/genética , Línea Celular Tumoral , Dimerización , Humanos , Inmunoprecipitación , Neoplasias/terapia , Transducción de SeñalRESUMEN
In recent years, the research community has, with comprehensive systems biology approaches and related technologies, gained insight into the vast complexity of numerous cancers. These approaches allow an in-depth exploration that cannot be achieved solely using conventional low-throughput methods, which do not closely mimic the natural cellular environment. In this review, we discuss recent integrative multiple omics approaches for understanding and modulating previously identified 'undruggable' targets such as members of the RAS family, MYC, TP53, and various E3 ligases and deubiquitinases. We describe how these technologies have revolutionized drug discovery by overcoming an array of biological and technological challenges and how, in the future, they will be pivotal in assessing cancer states in individual patients, allowing for the prediction and application of personalized disease treatments.
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Neoplasias , Biología de Sistemas , Descubrimiento de Drogas , Humanos , Neoplasias/tratamiento farmacológico , Neoplasias/metabolismo , Ubiquitina-Proteína LigasasRESUMEN
Protein-protein interactions (PPIs) play essential roles in Anaplastic Lymphoma Kinase (ALK) signaling. Systematic characterization of ALK interactors helps elucidate novel ALK signaling mechanisms and may aid in the identification of novel therapeutics targeting related diseases. In this study, we used the Mammalian Membrane Two-Hybrid (MaMTH) system to map the phospho-dependent ALK interactome. By screening a library of 86 SH2 domain-containing full length proteins, 30 novel ALK interactors were identified. Many of their interactions are correlated to ALK phosphorylation activity: oncogenic ALK mutations potentiate the interactions and ALK inhibitors attenuate the interactions. Among the novel interactors, NCK2 was further verified in neuroblastoma cells using co-immunoprecipitation. Modulation of ALK activity by addition of inhibitors lead to concomitant changes in the tyrosine phosphorylation status of NCK2 in neuroblastoma cells, strongly supporting the functionality of the ALK/NCK2 interaction. Our study provides a resource list of potential novel ALK signaling components for further study.
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Quinasa de Linfoma Anaplásico/metabolismo , Proteínas Portadoras/metabolismo , Mapeo de Interacción de Proteínas , Transducción de Señal , Línea Celular Tumoral , Humanos , Fosforilación , Unión Proteica , Dominios y Motivos de Interacción de Proteínas , Mapeo de Interacción de Proteínas/métodosRESUMEN
Activating mutations in the epidermal growth factor receptor (EGFR) are common driver mutations in non-small cell lung cancer (NSCLC). First, second and third generation EGFR tyrosine kinase inhibitors (TKIs) are effective at inhibiting mutant EGFR NSCLC, however, acquired resistance is a major issue, leading to disease relapse. Here, we characterize a small molecule, EMI66, an analog of a small molecule which we previously identified to inhibit mutant EGFR signalling via a novel mechanism of action. We show that EMI66 attenuates receptor tyrosine kinase (RTK) expression and signalling and alters the electrophoretic mobility of Coatomer Protein Complex Beta 2 (COPB2) protein in mutant EGFR NSCLC cells. Moreover, we demonstrate that EMI66 can alter the subcellular localization of EGFR and COPB2 within the early secretory pathway. Furthermore, we find that COPB2 knockdown reduces the growth of mutant EGFR lung cancer cells, alters the post-translational processing of RTKs, and alters the endoplasmic reticulum (ER) stress response pathway. Lastly, we show that EMI66 treatment also alters the ER stress response pathway and inhibits the growth of mutant EGFR lung cancer cells and organoids. Our results demonstrate that targeting of COPB2 with EMI66 presents a viable approach to attenuate mutant EGFR signalling and growth in NSCLC.
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Proteína Coatómero/genética , Proteína Coatómero/metabolismo , Descubrimiento de Drogas , Estrés del Retículo Endoplásmico/efectos de los fármacos , Estrés del Retículo Endoplásmico/genética , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Proteínas Tirosina Quinasas Receptoras/genética , Descubrimiento de Drogas/métodos , Ensayos de Selección de Medicamentos Antitumorales , Receptores ErbB/antagonistas & inhibidores , Receptores ErbB/genética , Receptores ErbB/metabolismo , Humanos , Mutación , Inhibidores de Proteínas Quinasas/farmacología , Procesamiento Proteico-Postraduccional , Proteínas Tirosina Quinasas Receptoras/metabolismo , Transducción de Señal/efectos de los fármacosRESUMEN
Receptor tyrosine kinases (RTKs) are transmembrane receptors of great clinical interest due to their role in disease, notably cancer. Since their discovery, several mechanisms of RTK dysregulation have been identified, resulting in multiple cancer types displaying 'oncogenic addiction' to RTKs. As a result, RTKs have represented a major class for targeted therapeutics over the past two decades, with numerous small molecule-based tyrosine kinase inhibitor (TKI) therapeutics having been developed and clinically approved for several cancers. However, many of the current RTK inhibitor treatments eventually result in the rapid development of acquired resistance and subsequent tumor relapse. Recent technological advances and tools are being generated for the identification of novel RTK small molecule therapeutics. These newer technologies will be important for the identification of diverse types of RTK inhibitors, targeting both the receptors themselves as well as key cellular factors that play important roles in the RTK signaling cascade.
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Neoplasias/tratamiento farmacológico , Neoplasias/metabolismo , Oncogenes/efectos de los fármacos , Inhibidores de Proteínas Quinasas/farmacología , Tirosina/metabolismo , Animales , Humanos , Terapia Molecular Dirigida/métodosRESUMEN
Functional analysis of the Mtl1 protein in Saccharomyces cerevisiae has revealed that this transmembrane sensor endows yeast cells with resistance to oxidative stress through a signaling mechanism called the cell wall integrity pathway (CWI). We observed upregulation of multiple heat shock proteins (HSPs), proteins associated with the formation of stress granules, and the phosphatase subunit of trehalose 6-phosphate synthase which suggests that mtl1Δ strains undergo intrinsic activation of a non-lethal heat stress response. Furthermore, quantitative global proteomic analysis conducted on TMT-labeled proteins combined with metabolome analysis revealed that mtl1Δ strains exhibit decreased levels of metabolites of carboxylic acid metabolism, decreased expression of anabolic enzymes and increased expression of catabolic enzymes involved in the metabolism of amino acids, with enhanced expression of mitochondrial respirasome proteins. These observations support the idea that Mtl1 protein controls the suppression of a non-lethal heat stress response under normal conditions while it plays an important role in metabolic regulatory mechanisms linked to TORC1 signaling that are required to maintain cellular homeostasis and optimal mitochondrial function.
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Mecanotransducción Celular , Receptores de Superficie Celular/genética , Receptores de Superficie Celular/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/fisiología , Cromatografía Liquida , Biología Computacional/métodos , Curaduría de Datos , Perfilación de la Expresión Génica/métodos , Metabolómica/métodos , Mapeo de Interacción de Proteínas , Mapas de Interacción de Proteínas , Proteogenómica/métodos , Espectrometría de Masas en TándemRESUMEN
Better diagnostic tools are needed to combat the ongoing COVID-19 pandemic. Here, to meet this urgent demand, we report a homogeneous immunoassay to detect IgG antibodies against SARS-CoV-2. This serological assay, called SATiN, is based on a tri-part Nanoluciferase (tNLuc) approach, in which the spike protein of SARS-CoV-2 and protein G, fused respectively to two different tNLuc tags, are used as antibody probes. Target engagement of the probes allows reconstitution of a functional luciferase in the presence of the third tNLuc component. The assay is performed directly in the liquid phase of patient sera and enables rapid, quantitative and low-cost detection. We show that SATiN has a similar sensitivity to ELISA, and its readouts are consistent with various neutralizing antibody assays. This proof-of-principle study suggests potential applications in diagnostics, as well as disease and vaccination management.
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Anticuerpos Antivirales/sangre , Prueba de COVID-19/métodos , COVID-19/diagnóstico , Inmunoensayo/métodos , Luciferasas/metabolismo , SARS-CoV-2/inmunología , SARS-CoV-2/aislamiento & purificación , Anticuerpos Neutralizantes/sangre , Anticuerpos Antivirales/inmunología , COVID-19/sangre , COVID-19/virología , Ensayo de Inmunoadsorción Enzimática , Células HEK293 , Humanos , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , Glicoproteína de la Espiga del Coronavirus/inmunologíaRESUMEN
OBJECTIVE: Autophagy is a physiological self-eating process that can promote cell survival or activate cell death in eukaryotic cells. In skeletal muscle, it is important for maintaining muscle mass and function that is critical to sustain mobility and regulate metabolism. The UV radiation resistance-associated gene (UVRAG) regulates the early stages of autophagy and autophagosome maturation and plays a key role in endosomal trafficking. This study investigated the essential in vivo role of UVRAG in skeletal muscle biology. METHODS: To determine the role of UVRAG in skeletal muscle in vivo, we generated muscle-specific UVRAG knockout mice using the Cre-loxP system driven by Myf6 promoter that is exclusively expressed in skeletal muscle. Myf6-Cre+ UVRAGfl/fl (M-UVRAG-/-) mice were compared to littermate Myf6-Cre+ UVRAG+/+ (M-UVRAG+/+) controls under basal conditions on a normal chow diet. Body composition, muscle function, and mitochondria morphology were assessed in muscles of the WT and KO mice at 24 weeks of age. RESULTS: M-UVRAG-/- mice developed accelerated sarcopenia and impaired muscle function compared to M-UVRAG+/+ littermates at 24 weeks of age. Interestingly, these mice displayed improved glucose tolerance and increased energy expenditure likely related to upregulated Fgf21, a marker of muscle dysfunction. Skeletal muscle of the M-UVRAG-/- mice showed altered mitochondrial morphology with increased mitochondrial fission and EGFR accumulation reflecting defects in endosomal trafficking. To determine whether increased EGFR signaling had a causal role in muscle dysfunction, the mice were treated with an EGFR inhibitor, gefitinib, which partially restored markers of muscle and mitochondrial deregulation. Conversely, constitutively active EGFR transgenic expression in UVRAG-deficient muscle led to further detrimental effects with non-overlapping distinct defects in muscle function, with EGFR activation affecting the muscle fiber type whereas UVRAG deficiency impaired mitochondrial homeostasis. CONCLUSIONS: Our results show that both UVRAG and EGFR signaling are critical for maintaining muscle mass and function with distinct mechanisms in the differentiation pathway.