RESUMEN
Itch is an unpleasant sensation that evokes a desire to scratch. The skin barrier is constantly exposed to microbes and their products. However, the role of microbes in itch generation is unknown. Here, we show that Staphylococcus aureus, a bacterial pathogen associated with itchy skin diseases, directly activates pruriceptor sensory neurons to drive itch. Epicutaneous S. aureus exposure causes robust itch and scratch-induced damage. By testing multiple isogenic bacterial mutants for virulence factors, we identify the S. aureus serine protease V8 as a critical mediator in evoking spontaneous itch and alloknesis. V8 cleaves proteinase-activated receptor 1 (PAR1) on mouse and human sensory neurons. Targeting PAR1 through genetic deficiency, small interfering RNA (siRNA) knockdown, or pharmacological blockade decreases itch and skin damage caused by V8 and S. aureus exposure. Thus, we identify a mechanism of action for a pruritogenic bacterial factor and demonstrate the potential of inhibiting V8-PAR1 signaling to treat itch.
Asunto(s)
Péptido Hidrolasas , Prurito , Receptor PAR-1 , Infecciones Estafilocócicas , Staphylococcus aureus , Animales , Humanos , Ratones , Péptido Hidrolasas/metabolismo , Prurito/microbiología , Receptor PAR-1/metabolismo , Staphylococcus aureus/enzimología , Staphylococcus aureus/patogenicidad , Staphylococcus aureus/fisiología , Infecciones Estafilocócicas/microbiología , Infecciones Estafilocócicas/patologíaRESUMEN
It is unknown whether pangolins, the most trafficked mammals, play a role in the zoonotic transmission of bat coronaviruses. We report the circulation of a novel MERS-like coronavirus in Malayan pangolins, named Manis javanica HKU4-related coronavirus (MjHKU4r-CoV). Among 86 animals, four tested positive by pan-CoV PCR, and seven tested seropositive (11 and 12.8%). Four nearly identical (99.9%) genome sequences were obtained, and one virus was isolated (MjHKU4r-CoV-1). This virus utilizes human dipeptidyl peptidase-4 (hDPP4) as a receptor and host proteases for cell infection, which is enhanced by a furin cleavage site that is absent in all known bat HKU4r-CoVs. The MjHKU4r-CoV-1 spike shows higher binding affinity for hDPP4, and MjHKU4r-CoV-1 has a wider host range than bat HKU4-CoV. MjHKU4r-CoV-1 is infectious and pathogenic in human airways and intestinal organs and in hDPP4-transgenic mice. Our study highlights the importance of pangolins as reservoir hosts of coronaviruses poised for human disease emergence.
Asunto(s)
Infecciones por Coronavirus , Coronavirus , Dipeptidil Peptidasa 4 , Pangolines , Animales , Humanos , Ratones , Quirópteros , Infecciones por Coronavirus/veterinaria , Infecciones por Coronavirus/virología , Dipeptidil Peptidasa 4/genética , Dipeptidil Peptidasa 4/metabolismo , Endopeptidasas/metabolismo , Coronavirus del Síndrome Respiratorio de Oriente Medio/genética , Coronavirus del Síndrome Respiratorio de Oriente Medio/metabolismo , Péptido Hidrolasas/metabolismo , Receptores Virales/metabolismo , Internalización del Virus , Coronavirus/fisiologíaRESUMEN
Mitochondria are essential metabolic hubs that dynamically adapt to physiological demands. More than 40 proteases residing in different compartments of mitochondria, termed mitoproteases, preserve mitochondrial proteostasis and are emerging as central regulators of mitochondrial plasticity. These multifaceted enzymes limit the accumulation of short-lived, regulatory proteins within mitochondria, modulate the activity of mitochondrial proteins by protein processing, and mediate the degradation of damaged proteins. Various signaling cascades coordinate the activity of mitoproteases to preserve mitochondrial homeostasis and ensure cell survival. Loss of mitoproteases severely impairs the functional integrity of mitochondria, is associated with aging, and causes pleiotropic diseases. Understanding the dual function of mitoproteases as regulatory and quality control enzymes will help unravel the role of mitochondrial plasticity in aging and disease.
Asunto(s)
Envejecimiento/genética , Mitocondrias/genética , Proteínas Mitocondriales/química , Neoplasias/genética , Enfermedades Neurodegenerativas/genética , Péptido Hidrolasas/química , Envejecimiento/metabolismo , Animales , Apoptosis/genética , Regulación de la Expresión Génica , Homeostasis/genética , Humanos , Metabolismo de los Lípidos/genética , Mitocondrias/enzimología , Dinámicas Mitocondriales/genética , Proteínas Mitocondriales/genética , Proteínas Mitocondriales/metabolismo , Mitofagia/genética , Neoplasias/enzimología , Neoplasias/patología , Enfermedades Neurodegenerativas/enzimología , Enfermedades Neurodegenerativas/patología , Péptido Hidrolasas/genética , Péptido Hidrolasas/metabolismo , Fosfolípidos/metabolismo , Proteolisis , Proteostasis/genéticaRESUMEN
Interleukin-33 (IL-33), an epithelial cell-derived cytokine that responds rapidly to environmental insult, has a critical role in initiating airway inflammatory diseases. However, the molecular mechanism underlying IL-33 secretion following allergen exposure is not clear. Here, we found that two cell events were fundamental for IL-33 secretion after exposure to allergens. First, stress granule assembly activated by allergens licensed the nuclear-cytoplasmic transport of IL-33, but not the secretion of IL-33. Second, a neo-form murine amino-terminal p40 fragment gasdermin D (Gsdmd), whose generation was independent of inflammatory caspase-1 and caspase-11, dominated cytosolic secretion of IL-33 by forming pores in the cell membrane. Either the blockade of stress granule assembly or the abolishment of p40 production through amino acid mutation of residues 309-313 (ELRQQ) could efficiently prevent the release of IL-33 in murine epithelial cells. Our findings indicated that targeting stress granule disassembly and Gsdmd fragmentation could reduce IL-33-dependent allergic airway inflammation.
Asunto(s)
Alérgenos , Interleucina-33 , Proteínas de Unión a Fosfato/metabolismo , Proteínas Citotóxicas Formadoras de Poros/metabolismo , Animales , Caspasa 1/metabolismo , Inflamación , Interleucina-1beta/metabolismo , Interleucina-33/genética , Interleucina-33/metabolismo , Péptidos y Proteínas de Señalización Intracelular/genética , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Ratones , Péptido Hidrolasas/metabolismo , Gránulos de EstrésRESUMEN
Arc/Arg3.1 is required for synaptic plasticity and cognition, and mutations in this gene are linked to autism and schizophrenia. Arc bears a domain resembling retroviral/retrotransposon Gag-like proteins, which multimerize into a capsid that packages viral RNA. The significance of such a domain in a plasticity molecule is uncertain. Here, we report that the Drosophila Arc1 protein forms capsid-like structures that bind darc1 mRNA in neurons and is loaded into extracellular vesicles that are transferred from motorneurons to muscles. This loading and transfer depends on the darc1-mRNA 3' untranslated region, which contains retrotransposon-like sequences. Disrupting transfer blocks synaptic plasticity, suggesting that transfer of dArc1 complexed with its mRNA is required for this function. Notably, cultured cells also release extracellular vesicles containing the Gag region of the Copia retrotransposon complexed with its own mRNA. Taken together, our results point to a trans-synaptic mRNA transport mechanism involving retrovirus-like capsids and extracellular vesicles.
Asunto(s)
Proteínas del Citoesqueleto/metabolismo , Productos del Gen gag/genética , Cuerpos Multivesiculares/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Terminales Presinápticos/metabolismo , ARN Mensajero/metabolismo , Animales , Transporte Biológico , Células Cultivadas , Proteínas del Citoesqueleto/química , Proteínas del Citoesqueleto/genética , Drosophila , Proteínas de Drosophila/genética , Proteínas de Drosophila/metabolismo , Productos del Gen gag/química , Proteínas del Tejido Nervioso/química , Proteínas del Tejido Nervioso/genética , Unión Neuromuscular/metabolismo , Plasticidad Neuronal , Péptido Hidrolasas/genética , Péptido Hidrolasas/metabolismo , Terminales Presinápticos/fisiología , Unión Proteica , Dominios Proteicos , Retroelementos/genéticaRESUMEN
Alzheimer's disease (AD)-linked mutations in Presenilins (PSEN) and the amyloid precursor protein (APP) lead to production of longer amyloidogenic Aß peptides. The shift in Aß length is fundamental to the disease; however, the underlying mechanism remains elusive. Here, we show that substrate shortening progressively destabilizes the consecutive enzyme-substrate (E-S) complexes that characterize the sequential γ-secretase processing of APP. Remarkably, pathogenic PSEN or APP mutations further destabilize labile E-S complexes and thereby promote generation of longer Aß peptides. Similarly, destabilization of wild-type E-S complexes by temperature, compounds, or detergent promotes release of amyloidogenic Aß. In contrast, E-Aßn stabilizers increase γ-secretase processivity. Our work presents a unifying model for how PSEN or APP mutations enhance amyloidogenic Aß production, suggests that environmental factors may increase AD risk, and provides the theoretical basis for the development of γ-secretase/substrate stabilizing compounds for the prevention of AD.
Asunto(s)
Enfermedad de Alzheimer/enzimología , Enfermedad de Alzheimer/genética , Precursor de Proteína beta-Amiloide/metabolismo , Proteínas de la Membrana/metabolismo , Péptido Hidrolasas/metabolismo , Presenilina-1/metabolismo , Precursor de Proteína beta-Amiloide/química , Animales , Encéfalo/metabolismo , Encéfalo/patología , Línea Celular , Endopeptidasas , Estabilidad de Enzimas , Femenino , Células HEK293 , Humanos , Proteínas de la Membrana/química , Proteínas de la Membrana/genética , Ratones , Modelos Moleculares , Mutación , Péptido Hidrolasas/química , Péptido Hidrolasas/genética , Presenilina-1/química , Presenilina-1/genéticaRESUMEN
Cellular proteostasis requires transport of polypeptides across membranes. Although defective transport processes trigger cytosolic rescue and quality control mechanisms that clear translocases and membranes from unproductive cargo, proteins that are synthesized within mitochondria are not accessible to these mechanisms. Mitochondrial-encoded proteins are inserted cotranslationally into the inner membrane by the conserved insertase OXA1L. Here, we identify TMEM126A as a OXA1L-interacting protein. TMEM126A associates with mitochondrial ribosomes and translation products. Loss of TMEM126A leads to the destabilization of mitochondrial translation products, triggering an inner membrane quality control process, in which newly synthesized proteins are degraded by the mitochondrial iAAA protease. Our data reveal that TMEM126A cooperates with OXA1L in protein insertion into the membrane. Upon loss of TMEM126A, the cargo-blocked OXA1L insertase complexes undergo proteolytic clearance by the iAAA protease machinery together with its cargo.
Asunto(s)
Mitocondrias , Membranas Mitocondriales , Mitocondrias/genética , Mitocondrias/metabolismo , Membranas Mitocondriales/metabolismo , Proteínas Mitocondriales/metabolismo , Biosíntesis de Proteínas , Ribosomas/metabolismo , Péptido Hidrolasas/metabolismoRESUMEN
Intramembrane proteases hydrolyze peptide bonds within the cell membrane as the decision-making step of various signaling pathways or during general proteostasis. Although initially thought to be rare, fourteen proteases from four superfamilies are now known to be distributed among nearly every membrane compartment of a human cell. Each protease is endowed with specific enzymatic properties that determine both substrate choice and outcome.
Asunto(s)
Membrana Celular/metabolismo , Péptido Hidrolasas/análisis , Proteolisis , Animales , Membrana Celular/enzimología , Humanos , Péptido Hidrolasas/metabolismoRESUMEN
Proteases are signaling molecules that specifically control cellular functions by cleaving protease-activated receptors (PARs). The four known PARs are members of the large family of G protein-coupled receptors. These transmembrane receptors control most physiological and pathological processes and are the target of a large proportion of therapeutic drugs. Signaling proteases include enzymes from the circulation; from immune, inflammatory epithelial, and cancer cells; as well as from commensal and pathogenic bacteria. Advances in our understanding of the structure and function of PARs provide insights into how diverse proteases activate these receptors to regulate physiological and pathological processes in most tissues and organ systems. The realization that proteases and PARs are key mediators of disease, coupled with advances in understanding the atomic level structure of PARs and their mechanisms of signaling in subcellular microdomains, has spurred the development of antagonists, some of which have advanced to the clinic. Herein we review the discovery, structure, and function of this receptor system, highlight the contribution of PARs to homeostatic control, and discuss the potential of PAR antagonists for the treatment of major diseases.
Asunto(s)
Receptores Proteinasa-Activados , Transducción de Señal , Humanos , Transducción de Señal/fisiología , Receptores Acoplados a Proteínas G , Péptido Hidrolasas/metabolismo , HomeostasisRESUMEN
In the type III-E CRISPR-Cas system, a Cas effector (gRAMP) is associated with a TPR-CHAT to form Craspase (CRISPR-guided caspase). However, both the structural features of gRAMP and the immunity mechanism remain unknown for this system. Here, we report structures of gRAMP-crRNA and gRAMP:cRNA:target RNA as well as structures of Craspase and Craspase complexed with cognate target RNA (CTR) or non-cognate target RNA (NTR). Importantly, the 3' anti-tag region of NTR and CTR binds at two distinct channels in Craspase, and CTR with a non-complementary 3' anti-tag induces a marked conformational change of the TPR-CHAT, which allosterically activates its protease activity to cleave an ancillary protein Csx30. This cleavage then triggers an abortive infection as the antiviral strategy of the type III-E system. Together, our study provides crucial insights into both the catalytic mechanism of the gRAMP and the immunity mechanism of the type III-E system.
Asunto(s)
Proteínas Asociadas a CRISPR , Proteínas Asociadas a CRISPR/genética , ARN/metabolismo , Antivirales , Sistemas CRISPR-Cas , Péptido Hidrolasas/genética , Péptido Hidrolasas/metabolismoRESUMEN
The mTOR complex 1 (mTORC1) is an essential metabolic hub that coordinates cellular metabolism with the availability of nutrients, including amino acids. Sestrin2 has been identified as a cytosolic leucine sensor that transmits leucine status signals to mTORC1. In this study, we identify an E3 ubiquitin ligase RING finger protein 167 (RNF167) and a deubiquitinase STAMBPL1 that function in concert to control the polyubiquitination level of Sestrin2 in response to leucine availability. Ubiquitination of Sestrin2 promotes its interaction with GATOR2 and inhibits mTORC1 signaling. Bioinformatic analysis reveals decreased RNF167 expression and increased STAMBPL1 expression in gastric and colorectal tumors. Knockout of STAMBPL1 or correction of the heterozygous STAMBPL1 mutation in a human colon cancer cell line suppresses xenograft tumor growth. Lastly, a cell-permeable peptide that blocks the STAMBPL1-Sestrin2 interaction inhibits mTORC1 and provides a potential option for cancer therapy.
Asunto(s)
Neoplasias Colorrectales/enzimología , Péptido Hidrolasas/metabolismo , Neoplasias Gástricas/enzimología , Serina-Treonina Quinasas TOR/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Animales , Células CACO-2 , Proliferación Celular , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/patología , Progresión de la Enfermedad , Regulación Neoplásica de la Expresión Génica , Células HCT116 , Células HEK293 , Humanos , Leucina/metabolismo , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Ratones Endogámicos BALB C , Ratones Desnudos , Mutación , Proteínas Nucleares/metabolismo , Péptido Hidrolasas/genética , Transducción de Señal , Neoplasias Gástricas/genética , Neoplasias Gástricas/patología , Carga Tumoral , Ubiquitina-Proteína Ligasas/genética , UbiquitinaciónRESUMEN
Inflammation observed in SARS-CoV-2-infected patients suggests that inflammasomes, proinflammatory intracellular complexes, regulate various steps of infection. Lung epithelial cells express inflammasome-forming sensors and constitute the primary entry door of SARS-CoV-2. Here, we describe that the NLRP1 inflammasome detects SARS-CoV-2 infection in human lung epithelial cells. Specifically, human NLRP1 is cleaved at the Q333 site by multiple coronavirus 3CL proteases, which triggers inflammasome assembly and cell death and limits the production of infectious viral particles. Analysis of NLRP1-associated pathways unveils that 3CL proteases also inactivate the pyroptosis executioner Gasdermin D (GSDMD). Subsequently, caspase-3 and GSDME promote alternative cell pyroptosis. Finally, analysis of pyroptosis markers in plasma from COVID-19 patients with characterized severe pneumonia due to autoantibodies against, or inborn errors of, type I interferons (IFNs) highlights GSDME/caspase-3 as potential markers of disease severity. Overall, our findings identify NLRP1 as a sensor of SARS-CoV-2 infection in lung epithelia.
Asunto(s)
COVID-19 , Proteasas 3C de Coronavirus , Células Epiteliales , Inflamasomas , Proteínas NLR , SARS-CoV-2 , COVID-19/genética , COVID-19/metabolismo , COVID-19/virología , Caspasa 3/metabolismo , Proteasas 3C de Coronavirus/genética , Proteasas 3C de Coronavirus/metabolismo , Células Epiteliales/metabolismo , Humanos , Inflamasomas/genética , Inflamasomas/metabolismo , Pulmón/metabolismo , Pulmón/virología , Proteínas NLR/genética , Proteínas NLR/metabolismo , Péptido Hidrolasas/genética , Péptido Hidrolasas/metabolismo , Proteínas de Unión a Fosfato/genética , Proteínas de Unión a Fosfato/metabolismo , Proteínas Citotóxicas Formadoras de Poros/genética , Proteínas Citotóxicas Formadoras de Poros/metabolismo , Piroptosis , SARS-CoV-2/enzimología , SARS-CoV-2/genética , SARS-CoV-2/metabolismo , SARS-CoV-2/patogenicidadRESUMEN
The signal peptidase complex (SPC) is an essential membrane complex in the endoplasmic reticulum (ER), where it removes signal peptides (SPs) from a large variety of secretory pre-proteins with exquisite specificity. Although the determinants of this process have been established empirically, the molecular details of SP recognition and removal remain elusive. Here, we show that the human SPC exists in two functional paralogs with distinct proteolytic subunits. We determined the atomic structures of both paralogs using electron cryo-microscopy and structural proteomics. The active site is formed by a catalytic triad and abuts the ER membrane, where a transmembrane window collectively formed by all subunits locally thins the bilayer. Molecular dynamics simulations indicate that this unique architecture generates specificity for SPs based on the length of their hydrophobic segments.
Asunto(s)
Retículo Endoplásmico/enzimología , Péptido Hidrolasas/metabolismo , Señales de Clasificación de Proteína , Serina Endopeptidasas/metabolismo , Células A549 , Dominio Catalítico , Microscopía por Crioelectrón , Células HEK293 , Células Hep G2 , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Glicoproteínas de Membrana/química , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Proteínas Asociadas a Microtúbulos/genética , Proteínas Asociadas a Microtúbulos/metabolismo , Simulación de Dinámica Molecular , Péptido Hidrolasas/química , Péptido Hidrolasas/genética , Proteómica , Serina Endopeptidasas/química , Serina Endopeptidasas/genética , Relación Estructura-Actividad , Especificidad por Sustrato , Espectrometría de Masas en Tándem , Células U937RESUMEN
Hydrolase enzymes, including proteases, are encoded by 2-3% of the genes in the human genome and 14% of these enzymes are active drug targets1. However, the activities and substrate specificities of many proteases-especially those embedded in membranes-and other hydrolases remain unknown. Here we report a strategy for creating mechanism-based, light-activated protease and hydrolase substrate traps in complex mixtures and live mammalian cells. The traps capture substrates of hydrolases, which normally use a serine or cysteine nucleophile. Replacing the catalytic nucleophile with genetically encoded 2,3-diaminopropionic acid allows the first step reaction to form an acyl-enzyme intermediate in which a substrate fragment is covalently linked to the enzyme through a stable amide bond2; this enables stringent purification and identification of substrates. We identify new substrates for proteases, including an intramembrane mammalian rhomboid protease RHBDL4 (refs. 3,4). We demonstrate that RHBDL4 can shed luminal fragments of endoplasmic reticulum-resident type I transmembrane proteins to the extracellular space, as well as promoting non-canonical secretion of endogenous soluble endoplasmic reticulum-resident chaperones. We also discover that the putative serine hydrolase retinoblastoma binding protein 9 (ref. 5) is an aminopeptidase with a preference for removing aromatic amino acids in human cells. Our results exemplify a powerful paradigm for identifying the substrates and activities of hydrolase enzymes.
Asunto(s)
Péptido Hidrolasas , Serina Endopeptidasas , Animales , Proteínas de Ciclo Celular , Humanos , Péptidos y Proteínas de Señalización Intracelular , Mamíferos/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas de Neoplasias , Péptido Hidrolasas/metabolismo , Serina/metabolismo , Especificidad por SustratoRESUMEN
The ubiquitin E3 ligase substrate adapter cereblon (CRBN) is a target of thalidomide and lenalidomide1, therapeutic agents used in the treatment of haematopoietic malignancies2-4 and as ligands for targeted protein degradation5-7. These agents are proposed to mimic a naturally occurring degron; however, the structural motif recognized by the thalidomide-binding domain of CRBN remains unknown. Here we report that C-terminal cyclic imides, post-translational modifications that arise from intramolecular cyclization of glutamine or asparagine residues, are physiological degrons on substrates for CRBN. Dipeptides bearing the C-terminal cyclic imide degron substitute for thalidomide when embedded within bifunctional chemical degraders. Addition of the degron to the C terminus of proteins induces CRBN-dependent ubiquitination and degradation in vitro and in cells. C-terminal cyclic imides form adventitiously on physiologically relevant timescales throughout the human proteome to afford a degron that is endogenously recognized and removed by CRBN. The discovery of the C-terminal cyclic imide degron defines a regulatory process that may affect the physiological function and therapeutic engagement of CRBN.
Asunto(s)
Imidas , Proteolisis , Complejos de Ubiquitina-Proteína Ligasa , Humanos , Asparagina/química , Dipéptidos/farmacología , Glutamina/química , Imidas/química , Imidas/metabolismo , Lenalidomida/farmacología , Ligandos , Péptido Hidrolasas/metabolismo , Proteolisis/efectos de los fármacos , Proteoma/metabolismo , Talidomida/farmacología , Ubiquitinación/efectos de los fármacos , Secuencias de Aminoácidos , CiclizaciónRESUMEN
There are many large protein complexes involved in transcription in a chromatin context. However, recent studies on the SAGA coactivator complex are generating new paradigms for how the components of these complexes function, both independently and in concert. This review highlights the initial discovery of the canonical SAGA complex 23 years ago, our evolving understanding of its modular structure and the relevance of its modular nature for its coactivator function in gene regulation.
Asunto(s)
Regulación de la Expresión Génica/fisiología , Transactivadores/química , Transactivadores/metabolismo , Animales , Histona Acetiltransferasas/metabolismo , Complejos Multiproteicos/metabolismo , Péptido Hidrolasas/metabolismo , Subunidades de Proteína , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/metabolismo , Relación Estructura-Actividad , Factores Asociados con la Proteína de Unión a TATA/metabolismoRESUMEN
The COP9 signalosome (CSN) is a universal regulator of Cullin-RING ubiquitin ligases (CRLs) - a family of modular enzymes that control various cellular processes via timely degradation of key signaling proteins. The CSN, with its eight-subunit architecture, employs multisite binding of CRLs and inactivates CRLs by removing a small ubiquitin-like modifier named neural precursor cell-expressed, developmentally downregulated 8 (Nedd8). Besides the active site of the catalytic subunit CSN5, two allosteric sites are present in the CSN, one of which recognizes the substrate recognition module and the presence of CRL substrates, and the other of which can 'glue' the CSN-CRL complex by recruitment of inositol hexakisphosphate. In this review, we present recent findings on the versatile regulation of CSN-CRL complexes.
Asunto(s)
Proteínas Cullin , Complejos Multiproteicos , Complejos Multiproteicos/química , Proteínas Cullin/metabolismo , Complejo del Señalosoma COP9/metabolismo , Ubiquitina , Dominio Catalítico , Péptido Hidrolasas/metabolismo , Ubiquitina-Proteína Ligasas/metabolismoRESUMEN
Recent advances in mitochondrial biology have revealed the high diversity and complexity of proteolytic enzymes that regulate mitochondrial function. We have classified mitochondrial proteases, or mitoproteases, on the basis of their function and location, and defined the human mitochondrial degradome as the complete set of mitoproteases that are encoded by the human genome. In addition to their nonspecific degradative functions, mitoproteases perform highly regulated proteolytic reactions that are important in mitochondrial function, integrity and homeostasis. These include protein synthesis, quality control, mitochondrial biogenesis and dynamics, mitophagy and apoptosis. Impaired or dysregulated function of mitoproteases is associated with ageing and with many pathological conditions such as neurodegenerative disorders, metabolic syndromes and cancer. A better understanding of the mitochondrial proteolytic landscape and its modulation may contribute to improving human lifespan and 'healthspan'.
Asunto(s)
Envejecimiento/metabolismo , Síndrome Metabólico/enzimología , Mitocondrias/enzimología , Proteínas Mitocondriales/metabolismo , Proteínas de Neoplasias/metabolismo , Neoplasias/enzimología , Enfermedades Neurodegenerativas/enzimología , Péptido Hidrolasas/metabolismo , Envejecimiento/genética , Envejecimiento/patología , Animales , Genoma Humano , Humanos , Síndrome Metabólico/genética , Síndrome Metabólico/patología , Mitocondrias/genética , Mitocondrias/patología , Proteínas Mitocondriales/genética , Proteínas de Neoplasias/genética , Neoplasias/genética , Neoplasias/patología , Enfermedades Neurodegenerativas/genética , Enfermedades Neurodegenerativas/patología , Péptido Hidrolasas/genética , ProteolisisRESUMEN
Staphylococcus aureus skin colonization and eosinophil infiltration are associated with many inflammatory skin disorders, including atopic dermatitis, bullous pemphigoid, Netherton's syndrome, and prurigo nodularis. However, whether there is a relationship between S. aureus and eosinophils and how this interaction influences skin inflammation is largely undefined. We show in a preclinical mouse model that S. aureus epicutaneous exposure induced eosinophil-recruiting chemokines and eosinophil infiltration into the skin. Remarkably, we found that eosinophils had a comparable contribution to the skin inflammation as T cells, in a manner dependent on eosinophil-derived IL-17A and IL-17F production. Importantly, IL-36R signaling induced CCL7-mediated eosinophil recruitment to the inflamed skin. Last, S. aureus proteases induced IL-36α expression in keratinocytes, which promoted infiltration of IL-17-producing eosinophils. Collectively, we uncovered a mechanism for S. aureus proteases to trigger eosinophil-mediated skin inflammation, which has implications in the pathogenesis of inflammatory skin diseases.
Asunto(s)
Dermatitis Atópica , Eosinofilia , Infecciones Estafilocócicas , Animales , Ratones , Eosinófilos/metabolismo , Staphylococcus aureus/metabolismo , Péptido Hidrolasas/metabolismo , Piel/metabolismo , Dermatitis Atópica/metabolismo , Infecciones Estafilocócicas/metabolismo , Celulitis (Flemón)/metabolismo , Celulitis (Flemón)/patología , Inflamación/metabolismoRESUMEN
The ClpP serine peptidase is a tetradecameric degradation molecular machine involved in many physiological processes. It becomes a competent ATP-dependent protease when coupled with Clp-ATPases. Small chemical compounds, acyldepsipeptides (ADEPs), are known to cause the dysregulation and activation of ClpP without ATPases and have potential as novel antibiotics. Previously, structural studies of ClpP from various species revealed its structural details, conformational changes, and activation mechanism. Although product release through side exit pores has been proposed, the detailed driving force for product release remains elusive. Herein, we report crystal structures of ClpP from Bacillus subtilis (BsClpP) in unforeseen ADEP-bound states. Cryo-electron microscopy structures of BsClpP revealed various conformational states under different pH conditions. To understand the conformational change required for product release, we investigated the relationship between substrate hydrolysis and the pH-lowering process. The production of hydrolyzed peptides from acidic and basic substrates by proteinase K and BsClpP lowered the pH values. Our data, together with those of previous findings, provide insight into the molecular mechanism of product release by the ClpP self-compartmentalizing protease.