RESUMO
Click chemistry, also known as "link chemistry," is an important molecular connection method that can achieve simple and efficient connections between specific small molecular groups at the molecular level. Click chemistry offers several advantages, including high efficiency, good selectivity, mild conditions, and few side reactions. These features make it a valuable tool for in-depth analysis of various protein posttranslational modifications (PTMs) caused by changes in cell metabolism during viral infection. This chapter considers the palmitoylation, carbonylation, and alkylation of STING and presents detailed information and experimental procedures for measuring PTMs using click chemistry.
Assuntos
Química Click , Processamento de Proteína Pós-Traducional , Química Click/métodos , Humanos , Alquilação , Lipoilação , Proteínas de Membrana/metabolismo , Proteínas de Membrana/química , Carbonilação ProteicaRESUMO
Palmitoylation, a lipid-based posttranslational protein modification, plays a crucial role in regulating various aspects of neuronal function through altering protein membrane-targeting, stabilities, and protein-protein interaction profiles. Disruption of palmitoylation has recently garnered attention as disease mechanism in neurodegeneration. Many proteins implicated in neurodegenerative diseases and associated neuronal dysfunction, including but not limited to amyloid precursor protein, ß-secretase (BACE1), postsynaptic density protein 95, Fyn, synaptotagmin-11, mutant huntingtin, and mutant superoxide dismutase 1, undergo palmitoylation, and recent evidence suggests that altered palmitoylation contributes to the pathological characteristics of these proteins and associated disruption of cellular processes. In addition, dysfunction of enzymes that catalyze palmitoylation and depalmitoylation has been connected to the development of neurological disorders. This review highlights some of the latest advances in our understanding of palmitoylation regulation in neurodegenerative diseases and explores potential therapeutic implications.
Assuntos
Lipoilação , Doenças Neurodegenerativas , Humanos , Doenças Neurodegenerativas/metabolismo , Doenças Neurodegenerativas/genética , Animais , Processamento de Proteína Pós-TraducionalRESUMO
Glutathione transferase P1 (GSTP1) is a multi-functional protein that protects cells from electrophiles by catalyzing their conjugation with glutathione, and contributes to the regulation of cell proliferation, apoptosis, and signalling. GSTP1, usually described as a cytosolic enzyme, can localize to other cell compartments and we have reported its strong association with the plasma membrane. In the current study, the hypothesis that GSTP1 is palmitoylated and this modification facilitates its dynamic localization and function was investigated. Palmitoylation is the reversible post-translational addition of a 16-C saturated fatty acid to proteins, most commonly on Cys residues through a thioester bond. GSTP1 in MCF7 cells was modified by palmitate, however, GSTP1 Cys to Ser mutants (individual and Cys-less) retained palmitoylation. Treatment of palmitoylated GSTP1 with 0.1 N NaOH, which cleaves ester bonds, did not remove palmitate. Purified GSTP1 was spontaneously palmitoylated in vitro and peptide sequencing revealed that Cys48 and Cys102 undergo S-palmitoylation, while Lys103 undergoes the rare N-palmitoylation. N-palmitoylation occurs via a stable NaOH-resistant amide bond. Analysis of subcellular fractions of MCF7-GSTP1 cells and a modified proximity ligation assay revealed that palmitoylated GSTP1 was present not only in the membrane fraction but also in the cytosol. GSTP1 isolated from E. coli, and MCF7 cells (grown under fatty acid free or regular conditions), associated with plasma membrane-enriched fractions and this association was not altered by palmitoyl CoA. Overall, GSTP1 is modified by palmitate, at multiple sites, including at least one non-Cys residue. These modifications could contribute to regulating the diverse functions of GSTP1.
Assuntos
Glutationa S-Transferase pi , Lipoilação , Palmitatos , Humanos , Glutationa S-Transferase pi/metabolismo , Glutationa S-Transferase pi/genética , Glutationa S-Transferase pi/química , Células MCF-7 , Palmitatos/metabolismo , Membrana Celular/metabolismo , Citosol/metabolismo , Cisteína/metabolismo , Processamento de Proteína Pós-Traducional , Ácido Palmítico/metabolismoRESUMO
Rap2b, a proto-oncogene upregulated in colorectal cancer (CRC), undergoes protein S-palmitoylation at specific C-terminus sites (C176/C177). These palmitoylation sites are crucial for Rap2b localization on the plasma membrane (PM), as mutation of C176 or C177 results in cytosolic relocation of Rap2b. Our study demonstrates that Rap2b influences cell migration and invasion in CRC cells, independent of proliferation, and this activity relies on its palmitoylation. We identify ABHD17a as the depalmitoylating enzyme for Rap2b, altering PM localization and inhibiting cell migration and invasion. EGFR/PI3K signaling regulates Rap2b palmitoylation, with PI3K phosphorylating ABHD17a to modulate its activity. These findings highlight the potential of targeting Rap2b palmitoylation as an intervention strategy. Blocking the C176/C177 sites using an interacting peptide attenuates Rap2b palmitoylation, disrupting PM localization, and suppressing CRC metastasis. This study offers insights into therapeutic approaches targeting Rap2b palmitoylation for the treatment of metastatic CRC, presenting opportunities to improve patient outcomes.
Assuntos
Membrana Celular , Neoplasias Colorretais , Lipoilação , Proteínas rap de Ligação ao GTP , Animais , Humanos , Camundongos , Linhagem Celular Tumoral , Membrana Celular/metabolismo , Movimento Celular , Proliferação de Células , Neoplasias Colorretais/patologia , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/genética , Receptores ErbB/metabolismo , Camundongos Nus , Metástase Neoplásica , Fosfatidilinositol 3-Quinases/metabolismo , Proto-Oncogene Mas , Proteínas rap de Ligação ao GTP/metabolismo , Proteínas rap de Ligação ao GTP/genética , Transdução de SinaisRESUMO
Innate immunity serves as the primary defense against viral and microbial infections in humans. The precise influence of cellular metabolites, especially fatty acids, on antiviral innate immunity remains largely elusive. Here, through screening a metabolite library, palmitic acid (PA) has been identified as a key modulator of antiviral infections in human cells. Mechanistically, PA induces mitochondrial antiviral signaling protein (MAVS) palmitoylation, aggregation, and subsequent activation, thereby enhancing the innate immune response. The palmitoyl-transferase ZDHHC24 catalyzes MAVS palmitoylation, thereby boosting the TBK1-IRF3-interferon (IFN) pathway, particularly under conditions of PA stimulation or high-fat-diet-fed mouse models, leading to antiviral immune responses. Additionally, APT2 de-palmitoylates MAVS, thus inhibiting antiviral signaling, suggesting that its inhibitors, such as ML349, effectively reverse MAVS activation in response to antiviral infections. These findings underscore the critical role of PA in regulating antiviral innate immunity through MAVS palmitoylation and provide strategies for enhancing PA intake or targeting APT2 for combating viral infections.
Assuntos
Aciltransferases , Proteínas Adaptadoras de Transdução de Sinal , Imunidade Inata , Fator Regulador 3 de Interferon , Lipoilação , Ácido Palmítico , Transdução de Sinais , Imunidade Inata/efeitos dos fármacos , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/imunologia , Humanos , Animais , Ácido Palmítico/farmacologia , Camundongos , Células HEK293 , Fator Regulador 3 de Interferon/metabolismo , Fator Regulador 3 de Interferon/genética , Fator Regulador 3 de Interferon/imunologia , Aciltransferases/genética , Aciltransferases/imunologia , Aciltransferases/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Serina-Treonina Quinases/genética , Camundongos Endogâmicos C57BL , Antivirais/farmacologia , Proteínas de Neoplasias , Peptídeos e Proteínas de Sinalização IntracelularRESUMO
The downregulation of Cadm4 (Cell adhesion molecular 4) is a prominent feature in demyelination diseases, yet, the underlying molecular mechanism remains elusive. Here, we reveal that Cadm4 undergoes specific palmitoylation at cysteine-347 (C347), which is crucial for its stable localization on the plasma membrane (PM). Mutation of C347 to alanine (C347A), blocking palmitoylation, causes Cadm4 internalization from the PM and subsequent degradation. In vivo experiments introducing the C347A mutation (Cadm4-KI) lead to severe myelin abnormalities in the central nervous system (CNS), characterized by loss, demyelination, and hypermyelination. We further identify ZDHHC3 (Zinc finger DHHC-type palmitoyltransferase 3) as the enzyme responsible for catalyzing Cadm4 palmitoylation. Depletion of ZDHHC3 reduces Cadm4 palmitoylation and diminishes its PM localization. Remarkably, genetic deletion of ZDHHC3 results in decreased Cadm4 palmitoylation and defects in CNS myelination, phenocopying the Cadm4-KI mouse model. Consequently, altered Cadm4 palmitoylation impairs neuronal transmission and cognitive behaviors in both Cadm4-KI and ZDHHC3 knockout mice. Importantly, attenuated ZDHHC3-Cadm4 signaling significantly influences neuroinflammation in diverse demyelination diseases. Mechanistically, we demonstrate the predominant expression of Cadm4 in the oligodendrocyte lineage and its potential role in modulating cell differentiation via the WNT-ß-Catenin pathway. Together, our findings propose that dysregulated ZDHHC3-Cadm4 signaling contributes to myelin abnormalities, suggesting a common pathological mechanism underlying demyelination diseases associated with neuroinflammation.
Assuntos
Aciltransferases , Sistema Nervoso Central , Lipoilação , Bainha de Mielina , Lipoilação/genética , Animais , Aciltransferases/genética , Camundongos , Humanos , Bainha de Mielina/genética , Bainha de Mielina/metabolismo , Bainha de Mielina/patologia , Sistema Nervoso Central/metabolismo , Sistema Nervoso Central/patologia , Moléculas de Adesão Celular/genética , Moléculas de Adesão Celular/metabolismo , Doenças Desmielinizantes/genética , Doenças Desmielinizantes/patologia , Doenças Desmielinizantes/metabolismo , Camundongos KnockoutRESUMO
Here, we present an optimized acyl-PEGyl exchange gel shift (APEGS) assay to monitor palmitoylation of high-molecular-weight proteins from primary neuronal cultures. We describe steps for culturing cortical neurons from rat embryos and expressing proteins of interest. We then detail procedures for employing a fatty acyl exchange technique wherein hydroxylamine is used to cleave palmitic acid from the palmitoyl-thioester bond, exposing cysteine residues that are subsequently labeled with methoxy polyethylene glycol maleimide (mPEG-MAL-10k). For complete details on the use and execution of this protocol, please refer to Yucel et al.1.
Assuntos
Lipoilação , Neurônios , Polietilenoglicóis , Animais , Ratos , Polietilenoglicóis/química , Polietilenoglicóis/metabolismo , Neurônios/metabolismo , Neurônios/citologia , Células Cultivadas , Ácido Palmítico/metabolismo , Ácido Palmítico/química , Peso MolecularRESUMO
Alzheimer's disease (AD) is the leading form of dementia, characterized by the accumulation and aggregation of amyloid in brain. Transient receptor potential vanilloid 2 (TRPV2) is an ion channel involved in diverse physiopathological processes, including microglial phagocytosis. Previous studies suggested that cannabidiol (CBD), an activator of TRPV2, improves microglial amyloid-ß (Aß) phagocytosis by TRPV2 modulation. However, the molecular mechanism of TRPV2 in microglial Aß phagocytosis remains unknown. In this study, we aimed to investigate the involvement of TRPV2 channel in microglial Aß phagocytosis and the underlying mechanisms. Utilizing human datasets, mouse primary neuron and microglia cultures, and AD model mice, to evaluate TRPV2 expression and microglial Aß phagocytosis in both in vivo and in vitro. TRPV2 was expressed in cortex, hippocampus, and microglia.Cannabidiol (CBD) could activate and sensitize TRPV2 channel. Short-term CBD (1 week) injection intraperitoneally (i.p.) reduced the expression of neuroinflammation and microglial phagocytic receptors, but long-term CBD (3 week) administration (i.p.) induced neuroinflammation and suppressed the expression of microglial phagocytic receptors in APP/PS1 mice. Furthermore, the hyper-sensitivity of TRPV2 channel was mediated by tyrosine phosphorylation at the molecular sites Tyr(338), Tyr(466), and Tyr(520) by protein tyrosine kinase JAK1, and these sites mutation reduced the microglial Aß phagocytosis partially dependence on its localization. While TRPV2 was palmitoylated at Cys 277 site and blocking TRPV2 palmitoylation improved microglial Aß phagocytosis. Moreover, it was demonstrated that TRPV2 palmitoylation was dynamically regulated by ZDHHC21. Overall, our findings elucidated the intricate interplay between TRPV2 channel regulated by tyrosine phosphorylation/dephosphorylation and cysteine palmitoylation/depalmitoylation, which had divergent effects on microglial Aß phagocytosis. These findings provide valuable insights into the underlying mechanisms linking microglial phagocytosis and TRPV2 sensitivity, and offer potential therapeutic strategies for managing AD.
Assuntos
Peptídeos beta-Amiloides , Lipoilação , Camundongos Transgênicos , Microglia , Fagocitose , Canais de Cátion TRPV , Tirosina , Animais , Camundongos , Microglia/metabolismo , Microglia/efeitos dos fármacos , Canais de Cátion TRPV/metabolismo , Peptídeos beta-Amiloides/metabolismo , Fagocitose/efeitos dos fármacos , Humanos , Fosforilação/efeitos dos fármacos , Tirosina/metabolismo , Lipoilação/efeitos dos fármacos , Células Cultivadas , Doença de Alzheimer/metabolismo , Canabidiol/farmacologia , Camundongos Endogâmicos C57BL , Canais de CálcioRESUMO
Adult mammary stem cells (aMaSCs) are vital to tissue expansion and remodeling during the process of postnatal mammary development. The protein C receptor (Procr) is one of the well-identified surface markers of multipotent aMaSCs. However, an understanding of the regulatory mechanisms governing Procr's protein stability remains incomplete. In this study, we identified Glycoprotein m6a (Gpm6a) as a critical protein for aMaSC activity modulation by using the Gpm6a knockout mouse model. Interestingly, we determined that Gpm6a depletion results in a reduction of Procr protein stability. Mechanistically, Gpm6a regulates Procr protein stability by mediating the formation of lipid rafts, a process requiring Zdhhc1 and Zdhhc2 to palmitate Gpm6a at Cys17,18 and Cys246 sites. Our findings highlight an important mechanism involving Zdhhc1- and Zdhhc2-mediated Gpm6a palmitoylation for the regulation of Procr stability, aMaSC activity, and postnatal mammary development.
Assuntos
Aciltransferases , Lipoilação , Glândulas Mamárias Animais , Animais , Aciltransferases/metabolismo , Aciltransferases/genética , Glândulas Mamárias Animais/metabolismo , Glândulas Mamárias Animais/citologia , Camundongos , Feminino , Camundongos Knockout , Humanos , Microdomínios da Membrana/metabolismo , Células-Tronco/metabolismo , Células-Tronco/citologia , Estabilidade ProteicaRESUMO
The NLRP3 inflammasome is dysregulated in autoinflammatory disorders caused by inherited mutations and contributes to the pathogenesis of several chronic inflammatory diseases. In this study, we discovered that disulfiram, a safe US Food and Drug Administration (FDA)-approved drug, specifically inhibits the NLRP3 inflammasome but not the NLRC4 or AIM2 inflammasomes. Disulfiram suppresses caspase-1 activation, ASC speck formation, and pyroptosis induced by several stimuli that activate NLRP3. Mechanistically, NLRP3 is palmitoylated at cysteine 126, a modification required for its localization to the trans-Golgi network and inflammasome activation, which was inhibited by disulfiram. Administration of disulfiram to animals inhibited the NLRP3, but not NLRC4, inflammasome in vivo. Our study uncovers a mechanism by which disulfiram targets NLRP3 and provides a rationale for using a safe FDA-approved drug for the treatment of NLRP3-associated inflammatory diseases.
Assuntos
Dissulfiram , Inflamassomos , Lipoilação , Proteína 3 que Contém Domínio de Pirina da Família NLR , United States Food and Drug Administration , Dissulfiram/farmacologia , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Inflamassomos/metabolismo , Animais , Humanos , Camundongos , Lipoilação/efeitos dos fármacos , Camundongos Endogâmicos C57BL , Estados Unidos , Caspase 1/metabolismo , Células HEK293 , Aprovação de Drogas , Piroptose/efeitos dos fármacosRESUMO
Gasdermin D (GSDMD) executes the cell death program of pyroptosis by assembling into oligomers that permeabilize the plasma membrane. Here, by single-molecule imaging, we elucidate the yet unclear mechanism of Gasdermin D pore assembly and the role of cysteine residues in GSDMD oligomerization. We show that GSDMD preassembles at the membrane into dimeric and trimeric building blocks that can either be inserted into the membrane, or further assemble into higher-order oligomers prior to insertion into the membrane. The GSDMD residues Cys39, Cys57, and Cys192 are the only relevant cysteines involved in GSDMD oligomerization. S-palmitoylation of Cys192, combined with the presence of negatively-charged lipids, controls GSDMD membrane targeting. Simultaneous Cys39/57/192-to-alanine (Ala) mutations, but not Ala mutations of Cys192 or the Cys39/57 pair individually, completely abolish GSDMD insertion into artificial membranes as well as into the plasma membrane. Finally, either Cys192 or the Cys39/Cys57 pair are sufficient to enable formation of GSDMD dimers/trimers, but they are all required for functional higher-order oligomer formation. Overall, our study unveils a cooperative role of Cys192 palmitoylation-mediated membrane binding and Cys39/57/192-mediated oligomerization in GSDMD pore assembly. This study supports a model in which Gasdermin D oligomerization relies on a two-step mechanism mediated by specific cysteine residues.
Assuntos
Membrana Celular , Cisteína , Lipoilação , Proteínas de Ligação a Fosfato , Proteínas de Ligação a Fosfato/metabolismo , Proteínas de Ligação a Fosfato/genética , Cisteína/metabolismo , Humanos , Membrana Celular/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/genética , Multimerização Proteica , Células HEK293 , Animais , GasderminasRESUMO
Autophagy is a highly conserved process from yeast to mammals in which intracellular materials are engulfed by a double-membrane organelle called autophagosome and degrading materials by fusing with the lysosome. The process of autophagy is regulated by sequential recruitment and function of autophagy-related (Atg) proteins. Genetic hierarchical analyses show that the ULK1 complex comprised of ULK1-FIP200-ATG13-ATG101 translocating from the cytosol to autophagosome formation sites as a most upstream ATG factor; this translocation is critical in autophagy initiation. However, how this translocation occurs remains unclear. Here, we show that ULK1 is palmitoylated by palmitoyltransferase ZDHHC13 and translocated to the autophagosome formation site upon autophagy induction. We find that the ULK1 palmitoylation is required for autophagy initiation. Moreover, the ULK1 palmitoylated enhances the phosphorylation of ATG14L, which is required for activating PI3-Kinase and producing phosphatidylinositol 3-phosphate, one of the autophagosome membrane's lipids. Our results reveal how the most upstream ULK1 complex translocates to the autophagosome formation sites during autophagy.
Assuntos
Aciltransferases , Autofagossomos , Proteína Homóloga à Proteína-1 Relacionada à Autofagia , Proteínas Relacionadas à Autofagia , Autofagia , Peptídeos e Proteínas de Sinalização Intracelular , Lipoilação , Proteína Homóloga à Proteína-1 Relacionada à Autofagia/metabolismo , Proteína Homóloga à Proteína-1 Relacionada à Autofagia/genética , Autofagia/fisiologia , Humanos , Proteínas Relacionadas à Autofagia/metabolismo , Proteínas Relacionadas à Autofagia/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/genética , Fosforilação , Aciltransferases/metabolismo , Aciltransferases/genética , Autofagossomos/metabolismo , Células HEK293 , Fosfatos de Fosfatidilinositol/metabolismo , Animais , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transporte Vesicular/metabolismo , Proteínas Adaptadoras de Transporte Vesicular/genética , Transporte Proteico , Proteínas de Transporte VesicularRESUMO
BACKGROUND: Breast cancer (BC) ranks as the third most fatal malignant tumor worldwide, with a strong reliance on fatty acid metabolism. CLDN6, a candidate BC suppressor gene, was previously identified as a regulator of fatty acid biosynthesis; however, the underlying mechanism remains elusive. In this research, we aim to clarify the specific mechanism through which CLDN6 modulates fatty acid anabolism and its impact on BC growth and metastasis. METHODS: Cell function assays, tumor xenograft mouse models, and lung metastasis mouse models were conducted to evaluate BC growth and metastasis. Human palmitic acid assay, triglyceride assay, Nile red staining, and oil red O staining were employed to investigate fatty acid anabolism. Reverse transcription polymerase chain reaction (RT-PCR), western blot, immunohistochemistry (IHC) assay, nuclear fractionation, immunofluorescence (IF), immunoprecipitation and acyl-biotin exchange (IP-ABE), chromatin immunoprecipitation (ChIP), dual luciferase reporter assay, and co-immunoprecipitation (Co-IP) were applied to elucidate the underlying molecular mechanism. Moreover, tissue microarrays of BC were analyzed to explore the clinical implications. RESULTS: We identified that CLDN6 inhibited BC growth and metastasis by impeding RAS palmitoylation both in vitro and in vivo. We proposed a unique theory suggesting that CLDN6 suppressed RAS palmitoylation through SREBP1-modulated de novo palmitic acid synthesis. Mechanistically, CLDN6 interacted with MAGI2 to prevent KLF5 from entering the nucleus, thereby restraining SREBF1 transcription. The downregulation of SREBP1 reduced de novo palmitic acid synthesis, hindering RAS palmitoylation and subsequent endosomal sorting complex required for transport (ESCRT)-mediated plasma membrane localization required for RAS oncogenic activation. Besides, targeting inhibition of RAS palmitoylation synergized with CLDN6 to repress BC progression. CONCLUSIONS: Our findings provide compelling evidence that CLDN6 suppresses the palmitic acid-induced RAS palmitoylation through the MAGI2/KLF5/SREBP1 axis, thereby impeding BC malignant progression. These results propose a new insight that monitoring CLDN6 expression alongside targeting inhibition of palmitic acid-mediated palmitoylation could be a viable strategy for treating oncogenic RAS-driven BC.
Assuntos
Neoplasias da Mama , Proliferação de Células , Claudinas , Lipoilação , Proteína de Ligação a Elemento Regulador de Esterol 1 , Animais , Feminino , Humanos , Camundongos , Neoplasias da Mama/patologia , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/genética , Claudinas/metabolismo , Claudinas/genética , Regulação Neoplásica da Expressão Gênica , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/secundário , Camundongos Nus , Metástase Neoplásica , Proteínas ras/metabolismo , Proteínas ras/genética , Proteína de Ligação a Elemento Regulador de Esterol 1/metabolismo , Proteína de Ligação a Elemento Regulador de Esterol 1/genéticaRESUMO
NLRP3 inflammasome activation, essential for cytokine secretion and pyroptosis in response to diverse stimuli, is closely associated with various diseases. Upon stimulation, NLRP3 undergoes subcellular membrane trafficking and conformational rearrangements, preparing itself for inflammasome assembly at the microtubule-organizing center (MTOC). Here, we elucidate an orchestrated mechanism underlying these ordered processes using human and murine cells. Specifically, NLRP3 undergoes palmitoylation at two sites by palmitoyl transferase zDHHC1, facilitating its trafficking between subcellular membranes, including the mitochondria, trans-Golgi network (TGN), and endosome. This dynamic trafficking culminates in the localization of NLRP3 to the MTOC, where LATS1/2, pre-recruited to MTOC during priming, phosphorylates NLRP3 to further facilitate its interaction with NIMA-related kinase 7 (NEK7), ultimately leading to full NLRP3 activation. Consistently, Zdhhc1-deficiency mitigated LPS-induced inflammation and conferred protection against mortality in mice. Altogether, our findings provide valuable insights into the regulation of NLRP3 membrane trafficking and inflammasome activation, governed by palmitoylation and phosphorylation events.
Assuntos
Inflamassomos , Lipoilação , Proteína 3 que Contém Domínio de Pirina da Família NLR , Transporte Proteico , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Inflamassomos/metabolismo , Inflamassomos/genética , Animais , Fosforilação , Humanos , Camundongos , Células HEK293 , Quinases Relacionadas a NIMA/metabolismo , Quinases Relacionadas a NIMA/genética , Aciltransferases/metabolismo , Aciltransferases/genética , Centro Organizador dos Microtúbulos/metabolismo , Camundongos Endogâmicos C57BL , Rede trans-Golgi/metabolismo , Camundongos Knockout , Endossomos/metabolismo , Mitocôndrias/metabolismoRESUMO
Cysteine palmitoylation or S-palmitoylation catalyzed by the ZDHHC family of acyltransferases regulates the biological function of numerous mammalian proteins as well as viral proteins. However, understanding of the role of S-palmitoylation in antiviral immunity against RNA viruses remains very limited. The adaptor protein MAVS forms functionally essential prion-like aggregates upon activation by viral RNA-sensing RIG-I-like receptors. Here, we identify that MAVS, a C-terminal tail-anchored mitochondrial outer membrane protein, is S-palmitoylated by ZDHHC7 at Cys508, a residue adjacent to the tail-anchor transmembrane helix. Using superresolution microscopy and other biochemical techniques, we found that the mitochondrial localization of MAVS at resting state mainly depends on its transmembrane tail-anchor, without regulation by Cys508 S-palmitoylation. However, upon viral infection, MAVS S-palmitoylation stabilizes its aggregation on the mitochondrial outer membrane and thus promotes subsequent propagation of antiviral signaling. We further show that inhibition of MAVS S-palmitoylation increases the host susceptibility to RNA virus infection, highlighting the importance of S-palmitoylation in the antiviral innate immunity. Also, our results indicate ZDHHC7 as a potential therapeutic target for MAVS-related autoimmune diseases.
Assuntos
Aciltransferases , Proteínas Adaptadoras de Transdução de Sinal , Imunidade Inata , Lipoilação , Membranas Mitocondriais , Humanos , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Membranas Mitocondriais/metabolismo , Aciltransferases/metabolismo , Células HEK293 , Mitocôndrias/metabolismo , Animais , Cisteína/metabolismo , Transdução de Sinais/imunologia , Agregados ProteicosRESUMO
RAS GTPases associate with the biological membrane where they function as molecular switches to regulate cell growth. Recent studies indicate that RAS proteins oligomerize on membranes, and disrupting these assemblies represents an alternative therapeutic strategy. However, conflicting reports on RAS assemblies, ranging in size from dimers to nanoclusters, have brought to the fore key questions regarding the stoichiometry and parameters that influence oligomerization. Here, we probe three isoforms of RAS [Kirsten Rat Sarcoma viral oncogene (KRAS), Harvey Rat Sarcoma viral oncogene (HRAS), and Neuroblastoma oncogene (NRAS)] directly from membranes using mass spectrometry. We show that KRAS on membranes in the inactive state (GDP-bound) is monomeric but forms dimers in the active state (GTP-bound). We demonstrate that the small molecule BI2852 can induce dimerization of KRAS, whereas the binding of effector proteins disrupts dimerization. We also show that RAS dimerization is dependent on lipid composition and reveal that oligomerization of NRAS is regulated by palmitoylation. By monitoring the intrinsic GTPase activity of RAS, we capture the emergence of a dimer containing either mixed nucleotides or GDP on membranes. We find that the interaction of RAS with the catalytic domain of Son of Sevenless (SOScat) is influenced by membrane composition. We also capture the activation and monomer to dimer conversion of KRAS by SOScat. These results not only reveal the stoichiometry of RAS assemblies on membranes but also uncover the impact of critical factors on oligomerization, encompassing regulation by nucleotides, lipids, and palmitoylation.
Assuntos
Membrana Celular , Multimerização Proteica , Proteínas Proto-Oncogênicas p21(ras) , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteínas Proto-Oncogênicas p21(ras)/química , Humanos , Membrana Celular/metabolismo , Proteínas de Membrana/metabolismo , Proteínas de Membrana/química , Proteínas de Membrana/genética , GTP Fosfo-Hidrolases/metabolismo , GTP Fosfo-Hidrolases/química , GTP Fosfo-Hidrolases/genética , Lipoilação , Proteínas ras/metabolismo , Proteínas ras/química , Guanosina Trifosfato/metabolismo , Guanosina Difosfato/metabolismoRESUMO
Cells may undergo senescence in response to DNA damage, which is associated with cell cycle arrest, altered gene expression and altered cell morphology. Protein palmitoylation is one of the mechanisms by which the DNA damage response is regulated. Therefore, we hypothesized that protein palmitoylation played a role in regulation of the senescent phenotype. Here, we showed that treatment of senescent human vascular smooth muscle cells (VSMCs) with 2-bromopalmitate (2-BP), an inhibitor of protein acyltransferases, is associated with changes in different aspects of the senescent phenotype, including the resumption of cell proliferation, a decrease in DNA damage markers and the downregulation of senescence-associated ß-galactosidase activity. The effects were dose dependent and associated with significantly decreased total protein palmitoylation level. We also showed that the senescence-modifying properties of 2-BP were at least partially mediated by the downregulation of elements of DNA damage-related molecular pathways, such as phosphorylated p53. Our data suggest that cell senescence may be regulated by palmitoylation, which provides a new perspective on the role of this posttranslational modification in age-related diseases.
Assuntos
Senescência Celular , Dano ao DNA , Lipoilação , Palmitatos , Humanos , Senescência Celular/efeitos dos fármacos , Palmitatos/farmacologia , Lipoilação/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Fenótipo , Músculo Liso Vascular/efeitos dos fármacos , Músculo Liso Vascular/citologia , Músculo Liso Vascular/metabolismo , Miócitos de Músculo Liso/efeitos dos fármacos , Miócitos de Músculo Liso/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Células Cultivadas , beta-Galactosidase/metabolismoRESUMO
The Hippo tumor suppressor pathway controls transcription by regulating nuclear abundance of YAP and TAZ, which activate transcription with the TEAD1-TEAD4 DNA-binding proteins. Recently, several small-molecule inhibitors of YAP and TEADs have been reported, with some entering clinical trials for different cancers with Hippo pathway deregulation, most notably, mesothelioma. Using genome-wide CRISPR/Cas9 screens we reveal that mutations in genes from the Hippo, MAPK, and JAK-STAT signaling pathways all modulate the response of mesothelioma cell lines to TEAD palmitoylation inhibitors. By exploring gene expression programs of mutant cells, we find that MAPK pathway hyperactivation confers resistance to TEAD inhibition by reinstating expression of a subset of YAP/TAZ target genes. Consistent with this, combined inhibition of TEAD and the MAPK kinase MEK, synergistically blocks proliferation of multiple mesothelioma and lung cancer cell lines and more potently reduces the growth of patient-derived lung cancer xenografts in vivo. Collectively, we reveal mechanisms by which cells can overcome small-molecule inhibition of TEAD palmitoylation and potential strategies to enhance the anti-tumor activity of emerging Hippo pathway targeted therapies.
Assuntos
Proteínas de Ligação a DNA , Fatores de Transcrição de Domínio TEA , Fatores de Transcrição , Humanos , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Linhagem Celular Tumoral , Animais , Proteínas de Ligação a DNA/metabolismo , Proteínas de Ligação a DNA/genética , Via de Sinalização Hippo , Camundongos , Resistencia a Medicamentos Antineoplásicos/genética , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Lipoilação , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Transcrição Gênica/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto , Bibliotecas de Moléculas Pequenas/farmacologia , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , MutaçãoRESUMO
S-palmitoylation is a reversible and dynamic process that involves the addition of long-chain fatty acids to proteins. This protein modification regulates various aspects of protein function, including subcellular localization, stability, conformation, and biomolecular interactions. The zinc finger DHHC (ZDHHC) domain-containing protein family is the main group of enzymes responsible for catalyzing protein S-palmitoylation, and 23 members have been identified in mammalian cells. Many proteins that undergo S-palmitoylation have been linked to disease pathogenesis and progression, suggesting that the development of effective inhibitors is a promising therapeutic strategy. Reducing the protein S-palmitoylation level can target either the PATs directly or their substrates. However, there are rare clinically effective S-palmitoylation inhibitors. This review aims to provide an overview of the S-palmitoylation field, including the catalytic mechanism of ZDHHC, S-palmitoylation detection methods, and the functional impact of protein S-palmitoylation. Additionally, this review focuses on current strategies for expanding the chemical toolbox to develop novel and effective inhibitors that can reduce the level of S-palmitoylation of the target protein.
Assuntos
Lipoilação , Humanos , Aciltransferases/antagonistas & inibidores , Aciltransferases/metabolismo , Animais , Inibidores Enzimáticos/farmacologia , Inibidores Enzimáticos/química , Descoberta de Drogas/métodos , Processamento de Proteína Pós-TraducionalRESUMO
Palmitoylation is a type of lipid modification that plays an important role in various aspects of neuronal function. Over the past few decades, several studies have shown that the palmitoylation of synaptic proteins is involved in neurotransmission and synaptic functions. Palmitoyl acyltransferases (PATs), which belong to the DHHC family, are major players in the regulation of palmitoylation. Dysregulated palmitoylation of synaptic proteins and mutated/dysregulated DHHC proteins are associated with several neurodegenerative diseases, such as Alzheimer's disease (AD), Huntington's disease (HD), and Parkinson's disease (PD). In this review, we summarize the recent discoveries on the subcellular distribution of DHHC proteins and analyze their expression patterns in different brain cells. In particular, this review discusses how palmitoylation of synaptic proteins regulates synaptic vesicle exocytotic fusion and the localization, clustering, and transport of several postsynaptic receptors, as well as the role of palmitoylation of other proteins in regulating synaptic proteins. Additionally, some of the specific known associations of these factors with neurodegenerative disorders are explored, with a few suggestions for the development of therapeutic strategies. Finally, this review provides possible directions for future research to reveal detailed and specific mechanisms underlying the roles of synaptic protein palmitoylation.