RESUMEN
Receptor-interacting protein kinase-3 (RIP3 or RIPK3) is a central protein in necroptosis, but posttranslational processes that regulate RIP3 activity and stability remain poorly understood. Here, we identify pellino E3 ubiquitin protein ligase 1 (PELI1) as an E3 ligase that targets RIP3 for proteasome-dependent degradation. Phosphorylation of RIP3 on T182 leads to interaction with the forkhead-associated (FHA) domain of PELI1 and PELI1-mediated K48-linked polyubiquitylation of RIP3 on K363. This same phosphorylation event is also important for RIP3 kinase activity; thus, PELI1 preferentially targets kinase-active RIP3 for degradation. PELI1-mediated RIP3 degradation effectively prevents cell death triggered by RIP3 hyperactivation. Importantly, upregulated RIP3 expression in keratinocytes from toxic epidermal necrolysis (TEN) patients is correlated with low expression of PELI1, suggesting that loss of PELI1 may play a role in the pathogenesis of TEN. We propose that PELI1 may function to control inadvertent activation of RIP3, thus preventing aberrant cell death and maintaining cellular homeostasis.
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Queratinocitos/enzimología , Proteínas Nucleares/metabolismo , Complejo de la Endopetidasa Proteasomal/metabolismo , Proteína Serina-Treonina Quinasas de Interacción con Receptores/metabolismo , Síndrome de Stevens-Johnson/enzimología , Ubiquitina-Proteína Ligasas/metabolismo , Animales , Muerte Celular , Fibroblastos/enzimología , Fibroblastos/patología , Células HEK293 , Células HT29 , Células HeLa , Humanos , Queratinocitos/patología , Ratones , Proteínas Nucleares/genética , Fosforilación , Unión Proteica , Dominios y Motivos de Interacción de Proteínas , Proteolisis , Proteína Serina-Treonina Quinasas de Interacción con Receptores/genética , Transducción de Señal , Síndrome de Stevens-Johnson/genética , Síndrome de Stevens-Johnson/patología , Ubiquitina-Proteína Ligasas/genética , UbiquitinaciónRESUMEN
AIMS: Sirtuin 7 (SIRT7) plays an important role in tumor development, and has been characterized as a potent regulator of cellular stress. However, the effect of SIRT7 on sorafenib acquired resistance remains unclear and a possible anti-tumor mechanism beyond this process in HCC has not been clarified. We examined the therapeutic potential of SIRT7 and determined whether it functions synergistically with sorafenib to overcome chemoresistance. METHODS: Cancer Genome Atlas-liver HCC data and unbiased gene set enrichment analyses were used to identify SIRT7 as a potential effector molecule in sorafenib acquired resistance. Two types of SIRT7 chemical inhibitors were developed to evaluate its therapeutic properties when synergized with sorafenib. Mass spectrometry was performed to discover a direct target of SIRT7, DDX3X, and DDX3X deacetylation levels and protein stability were explored. Moreover, an in vivo xenograft model was used to confirm anti-tumor effect of SIRT7 and DDX3X chemical inhibitors combined with sorafenib. RESULTS: SIRT7 inhibition mediated DDX3X depletion can re-sensitize acquired sorafenib resistance by disrupting NLRP3 inflammasome assembly, finally suppressing hyperactive ERK1/2 signaling in response to NLRP3 inflammasome-mediated IL-1ß inhibition. CONCLUSIONS: SIRT7 is responsible for sorafenib acquired resistance, and its inhibition would be beneficial when combined with sorafenib by suppressing hyperactive pro-cell survival ERK1/2 signaling.
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Carcinoma Hepatocelular , Neoplasias Hepáticas , Sirtuinas , Humanos , Carcinoma Hepatocelular/tratamiento farmacológico , Carcinoma Hepatocelular/genética , Sorafenib/farmacología , Sorafenib/uso terapéutico , Neoplasias Hepáticas/tratamiento farmacológico , Neoplasias Hepáticas/genética , Inflamasomas/metabolismo , Inflamasomas/farmacología , Fosforilación , Proteína con Dominio Pirina 3 de la Familia NLR/genética , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Sistema de Señalización de MAP Quinasas , Resistencia a Antineoplásicos/genética , Línea Celular Tumoral , Proliferación Celular , ARN Helicasas DEAD-box/genética , ARN Helicasas DEAD-box/metabolismo , ARN Helicasas DEAD-box/farmacología , Sirtuinas/genética , Sirtuinas/metabolismo , Sirtuinas/farmacologíaRESUMEN
ZAP-70 is required for the initiation of T cell receptor (TCR) signaling, and Ssu72 is a phosphatase that regulates RNA polymerase II activity in the nucleus. However, the mechanism by which ZAP-70 regulates the fine-tuning of TCR signaling remains elusive. Here, we found that Ssu72 contributed to the fine-tuning of TCR signaling by acting as tyrosine phosphatase for ZAP-70. Affinity purification-mass spectrometry and an in vitro assay demonstrated specific interaction between Ssu72 and ZAP-70 in T cells. Upon TCR stimulation, Ssu72-deficient T cells increased the phosphorylation of ZAP-70 and downstream molecules and exhibited hyperresponsiveness, which was restored by reducing ZAP-70 phosphorylation. In vitro assay demonstrated that recombinant Ssu72 reduced tyrosine phosphorylation of ZAP-70 via phosphatase activity. Cd4-CreSsu72fl/fl mice showed a defect in the thymic development of invariant natural killer T cells and reductions in CD4+ and CD8+ T cell numbers in the periphery but more CD44hiCD62Llo memory T cells and fewer CD44loCD62Lhi naïve T cells, compared with wild-type mice. Furthermore, Cd4-CreSsu72fl/fl mice developed spontaneous inflammation at 6 mo. In conclusion, Ssu72 phosphatase regulates the fine-tuning of TCR signaling by binding to ZAP-70 and regulating its tyrosine phosphorylation, thereby preventing spontaneous inflammation.
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Linfocitos T CD8-positivos/inmunología , Inflamación/prevención & control , Células T de Memoria/inmunología , Fosfoproteínas Fosfatasas/fisiología , Receptores de Antígenos de Linfocitos T/metabolismo , Proteína Tirosina Quinasa ZAP-70/metabolismo , Animales , Comunicación Celular , Inflamación/etiología , Inflamación/metabolismo , Inflamación/patología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Fosforilación , Receptores de Antígenos de Linfocitos T/genética , Receptores de Antígenos de Linfocitos T/inmunología , Proteína Tirosina Quinasa ZAP-70/genéticaRESUMEN
Capacitors are essential components in modern electrical systems, functioning primarily to store electrical charges and regulate current flow. Capacitive sensors, developed in the 20th century, have become crucial in various applications, including touchscreens and smart devices, due to their ability to detect both metallic and non-metallic objects with high sensitivity and low energy consumption. The advancement of microelectromechanical systems (MEMS) and nanotechnology has significantly enhanced the capabilities of capacitive sensors, leading to unprecedented sensitivity, dynamic range, and cost-effectiveness. These sensors are integral to modern devices, enabling precise measurements of proximity, pressure, strain, and other parameters. This review provides a comprehensive overview of the development, fabrication, and integration of micro and nanostructured capacitive sensors. In terms of an electric field, the working and detection principles are discussed with analytical equations and our numerical results. The focus extends to novel fabrication methods using advanced materials to enhance sensitivities for various parameters, such as proximity, force, pressure, strain, temperature, humidity, and liquid sensing. Their applications are demonstrated in wearable devices, human-machine interfaces, biomedical sensing, health monitoring, robotics control, industrial monitoring, and molecular detection. By consolidating existing research, this review offers insights into the advancements and future directions of capacitive sensor technology.
RESUMEN
Hydrophobic interactions and hydrogen bonds are 2 types of noncovalent interactions that play distinct roles in the folding and structural stability of proteins. However, the specific roles of these interactions in hydrophobic or hydrophilic environments in α/ß-hydrolases are not fully understood. A hyperthermophilic esterase EstE1 in a dimer maintains the C-terminal ß8-α9 strand-helix via hydrophobic interactions (Phe276 and Leu299), constituting a closed dimer interface. Moreover, a mesophilic esterase rPPE in a monomer maintains the same strand-helix via a hydrogen bond (Tyr281 and Gln306). Unpaired polar residues (F276Y in EstE1 and Y281A/F and Q306A in rPPE) or reduced hydrophobic interactions (F276A/L299A in EstE1) between the ß8-α9 strand-helix decrease thermal stability. EstE1 (F276Y/L299Q) and rPPE WT, both with the ß8-α9 hydrogen bond, showed the same thermal stability as EstE1 WT and rPPE (Y281F/Q306L), which possess hydrophobic interactions instead. However, EstE1 (F276Y/L299Q) and rPPE WT exhibited higher enzymatic activity than EstE1 WT and rPPE (Y281F/Q306L), respectively. This suggests that α/ß-hydrolases favor the ß8-α9 hydrogen bond for catalytic activity in monomers or oligomers. Overall, these findings demonstrate how α/ß-hydrolases modulate hydrophobic interactions and hydrogen bonds to adapt to different environments. Both types of interactions contribute equally to thermal stability, but the hydrogen bond is preferred for catalytic activity. IMPORTANCE Esterases hydrolyze short to medium-chain monoesters and contain a catalytic His on a loop between the C-terminal ß8-strand and α9-helix. This study explores how hyperthermophilic esterase EstE1 and mesophilic esterase rPPE adapt to different temperatures by utilizing the ß8-α9 hydrogen bonds or hydrophobic interactions differently. EstE1 forms a hydrophobic dimer interface, while rPPE forms a monomer stabilized by a hydrogen bond. The study demonstrates that these enzymes stabilize ß8-α9 strand-helix differently but achieve similar thermal stability. While the ß8-α9 hydrogen bond or hydrophobic interactions contribute equally to thermal stability, the hydrogen bond provides higher activity due to increased catalytic His loop flexibility in both EstE1 and rPPE. These findings reveal how enzymes adapt to extreme environments while maintaining their functions and have implications for engineering enzymes with desired activities and stabilities.
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Proteínas Bacterianas , Esterasas , Esterasas/metabolismo , Proteínas Bacterianas/metabolismoRESUMEN
Pellino-1 plays a crucial role in cellular proliferation and regulates inflammatory processes. This study investigated Pellino-1 expression patterns and their relationship with CD4+ T-cell subsets in psoriasis patients. Group 1 comprised primarily biopsied psoriasis lesions from 378 patients, multiplex-immunostained for Pellino-1, CD4 and representative T helper (Th) cells (T-bet [Th1], GATA3 [Th2], and RORγt [Th17] and regulatory T cell [FoxP3] markers). Ki-67 labeling was evaluated in the epidermis. Group 2 comprised 43 Pellino-1-positive cases immunostained for Pellino-1 in both lesion and non-lesion skin biopsy samples. Five normal skin biopsies served as controls. Among 378 psoriasis cases, 293 (77.5%) were positive for Pellino-1 in the epidermis. Pellino-1-positivity was higher in psoriasis lesions than in non-lesions and normal skin (52.55% vs. 40.43% vs. 3.48%, p < 0.001; H-score, 72.08 vs. 47.55 vs. 4.40, p < 0.001, respectively). Pellino-1-positive cases also had a significantly higher Ki-67 labeling index (p < 0.001). Epidermal Pellino1-positivity was significantly associated with higher RORγt+ (p = 0.001) and FoxP3+ (p < 0.001) CD4+ T cell ratios but not T-bet+ and GATA3+ CD4+ T cell ratios. Among the CD4+ Pellino-1+ T-cell subsets, the CD4+ Pellino-1+ RORγt+ ratio was significantly associated with epidermal Pellinio-1 expression (p < 0.001). Pellino-1 expression is thus increased in psoriasis lesions and associated with increased epidermal proliferation and CD4+ T-cell subset infiltration, especially Th17 cells. This suggests that Pellino-1 could be a therapeutic target that simultaneously regulates psoriasis epidermal proliferation and immune interactions.
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Psoriasis , Células Th17 , Humanos , Miembro 3 del Grupo F de la Subfamilia 1 de Receptores Nucleares , Antígeno Ki-67/metabolismo , Epidermis/metabolismo , Psoriasis/tratamiento farmacológico , Proliferación Celular , Factores de Transcripción Forkhead/metabolismoRESUMEN
Roll-to-roll manufacturing systems have been widely adopted for their cost-effectiveness, eco-friendliness, and mass-production capabilities, utilizing thin and flexible substrates. However, in these systems, defects in the rotating components such as the rollers and bearings can result in severe defects in the functional layers. Therefore, the development of an intelligent diagnostic model is crucial for effectively identifying these rotating component defects. In this study, a quantitative feature-selection method, feature partial density, to develop high-efficiency diagnostic models was proposed. The feature combinations extracted from the measured signals were evaluated based on the partial density, which is the density of the remaining data excluding the highest class in overlapping regions and the Mahalanobis distance by class to assess the classification performance of the models. The validity of the proposed algorithm was verified through the construction of ranked model groups and comparison with existing feature-selection methods. The high-ranking group selected by the algorithm outperformed the other groups in terms of training time, accuracy, and positive predictive value. Moreover, the top feature combination demonstrated superior performance across all indicators compared to existing methods.
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Changes in the DNA damage response (DDR) and cellular metabolism are two important factors that allow cancer cells to proliferate. DDR is a set of events in which DNA damage is recognized, DNA repair factors are recruited to the site of damage, the lesion is repaired, and cellular responses associated with the damage are processed. In cancer, DDR is commonly dysregulated, and the enzymes associated with DDR are prone to changes in ubiquitination. Additionally, cellular metabolism, especially glycolysis, is upregulated in cancer cells, and enzymes in this metabolic pathway are modulated by ubiquitination. The ubiquitin-proteasome system (UPS), particularly E3 ligases, act as a bridge between cellular metabolism and DDR since they regulate the enzymes associated with the two processes. Hence, the E3 ligases with high substrate specificity are considered potential therapeutic targets for treating cancer. A number of small molecule inhibitors designed to target different components of the UPS have been developed, and several have been tested in clinical trials for human use. In this review, we discuss the role of ubiquitination on overall cellular metabolism and DDR and confirm the link between them through the E3 ligases NEDD4, APC/CCDH1, FBXW7, and Pellino1. In addition, we present an overview of the clinically important small molecule inhibitors and implications for their practical use.
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Neoplasias , Humanos , Ubiquitinación , Neoplasias/patología , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/metabolismo , Daño del ADN , Ubiquitina/metabolismo , Reparación del ADNRESUMEN
To improve the poor survival rate of lung cancer patients, we investigated the role of HDGF-related protein 3 (HRP-3) as a potential biomarker for lung cancer. The expression of endogenous HRP-3 in human lung cancer tissues and xenograft tumor models is indicative of its clinical relevance in lung cancer. Additionally, we demonstrated that HRP-3 directly binds to the E2F1 promoter on chromatin. Interestingly, HRP-3 depletion in A549 cells impedes the binding of HRP-3 to the E2F1 promoter; this in turn hampers the interaction between Histone H3/H4 and HDAC1/2 on the E2F1 promoter, while concomitantly inducing Histone H3/H4 acetylation around the E2F1 promoter. The enhanced Histone H3/H4 acetylation on the E2F1 promoter through HRP-3 depletion increases the transcription level of E2F1. Furthermore, the increased E2F1 transcription levels lead to the enhanced transcription of Cyclin E, known as the E2F1-responsive gene, thus inducing S-phase accumulation. Therefore, our study provides evidence for the utility of HRP-3 as a biomarker for the prognosis and treatment of lung cancer. Furthermore, we delineated the capacity of HRP-3 to regulate the E2F1 transcription level via histone deacetylation.
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Biomarcadores de Tumor/metabolismo , Ciclina E/metabolismo , Factor de Transcripción E2F1/genética , Histona Desacetilasas/metabolismo , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Neoplasias Pulmonares/patología , Células A549 , Animales , Línea Celular Tumoral , Regulación Neoplásica de la Expresión Génica , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Ratones , Trasplante de Neoplasias , Regiones Promotoras Genéticas , Transducción de SeñalRESUMEN
Recently, we reported that auditory fear conditioning leads to the presynaptic potentiation at lateral amygdala to basal amygdala (LA-BA) synapses that shares the mechanism with high-frequency stimulation (HFS)-induced long-term potentiation (LTP) ex vivo. In the present study, we further examined the molecular mechanisms underlying the HFS-induced presynaptic LTP. We found that a presynaptic elevation of Ca2+ was required for the LTP induction. Interestingly, the blockade of presynaptic but not postsynaptic HCN channels with ZD7288 completely abolished LTP induction. While ZD7288 did not alter basal synaptic transmission, the blocker fully reversed previously established LTP, indicating that HCN channels are also required for the maintenance of LTP. Indeed, HCN3 and HCN4 channels were preferentially localized in the presynaptic boutons of LA afferents. Furthermore, an inhibition of either GABAB receptors or GIRK channels eliminated the inhibitory effect of HCN blockade on the LTP induction. Collectively, we suggest that activation of presynaptic HCN channels may counteract membrane hyperpolarization during tetanic stimulation, and thereby contributes to the presynaptic LTP at LA-BA synapses.
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Complejo Nuclear Basolateral , Potenciación a Largo Plazo , Sinapsis , Transmisión Sináptica , Terminales PresinápticosRESUMEN
We investigate the enhancement in sensitivity when measuring a weak force through the optical response of an optomechanical oscillator driven by squeezed light. In the context of a quantum sensor based on cavity-optomechanics, the sensitivity scaling measured by the quantum Fisher information for a squeezed vacuum state pump is compared to that for a coherent state pump. We show that squeezed state inputs can produce noise levels below the standard quantum limit and even the Heisenberg limit in given regimes. This study shows that new pathways can be opened for enhanced quantum sensing with optomechanical systems conducive to measuring various physical quantities such as gravitational force, acceleration, and acoustics.
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Fault diagnosis systems are used to improve the productivity and reduce the costs of the manufacturing process. However, the feature variables in existing systems are extracted based on the classification performance of the final model, thereby limiting their applications to models with different conditions. This paper proposes an algorithm to improve the characteristics of feature variables by considering the cutting conditions. Regardless of the frequency band, the noise of the measurement data was reduced through an oversampling method, setting a window length through a cutter sampling frequency, and improving its sensitivity to shock signal. An experiment was subsequently performed to confirm the performance of the model. Using normal and wear tools on AI7075 and SM45C, the diagnosis accuracies were 97.1% and 95.6%, respectively, with a reduction of 85% and 83%, respectively, in the time required to develop a diagnosis model. Therefore, the proposed algorithm reduced the model computation time and developed a model with high accuracy by enhancing the characteristics of the feature variable. The results of this study can contribute significantly to the establishment of a high-precision monitoring system for various processing processes.
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Histone H2AX undergoes a phosphorylation switch from pTyr142 (H2AX-pY142) to pSer139 (γH2AX) in the DNA damage response (DDR); however, the functional role of H2AX-pY142 remains elusive. Here, we report a new layer of regulation involving transcription-coupled H2AX-pY142 in the DDR. We found that constitutive H2AX-pY142 generated by Williams-Beuren syndrome transcription factor (WSTF) interacts with RNA polymerase II (RNAPII) and is associated with RNAPII-mediated active transcription in proliferating cells. Also, removal of pre-existing H2AX-pY142 by ATM-dependent EYA1/3 phosphatases disrupts this association and requires for transcriptional silencing at transcribed active damage sites. The following recovery of H2AX-pY142 via translocation of WSTF to DNA lesions facilitates transcription-coupled homologous recombination (TC-HR) in the G1 phase, whereby RAD51 loading, but not RPA32, utilizes RNAPII-dependent active RNA transcripts as donor templates. We propose that the WSTF-H2AX-RNAPII axis regulates transcription and TC-HR repair to maintain genome integrity.
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Histonas/metabolismo , Reparación del ADN por Recombinación , Factores de Transcripción/metabolismo , Transcripción Genética , Línea Celular Tumoral , Proteínas de Unión al ADN/metabolismo , Fase G1/genética , Células HEK293 , Células HeLa , Histonas/química , Humanos , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Proteínas Nucleares/metabolismo , Fosforilación , Proteínas Tirosina Fosfatasas/metabolismo , ARN Polimerasa II/metabolismo , Tirosina/metabolismoRESUMEN
Gravure printing, which is a roll-to-roll printed electronics system suitable for high-speed patterning of functional layers have advantages of being applied to flexible webs in large areas. As each of the printing procedure from inking to doctoring followed by ink transferring and setting influences the quality of the pattern geometry, it is necessary to detect and diagnose factors causing the printing defects beforehand. Data acquisition with three triaxial acceleration sensors for fault diagnosis of four major defects such as doctor blade tilting fault was obtained. To improve the diagnosis performances, optimal sensor selection with Sensor Data Efficiency Evaluation, sensitivity evaluation for axis selection with Directional Nature of Fault and feature variable optimization with Feature Combination Matrix method was applied on the raw data to form a Smart Data. Each phase carried out on the raw data progressively enhanced the diagnosis results in contents of accuracy, positive predictive value, diagnosis processing time, and data capacity. In the case of doctor blade tilting fault, the diagnosis accuracy increased from 48% to 97% with decreasing processing time of 3640 s to 16 s and the data capacity of 100 Mb to 5 Mb depending on the input data between raw data and Smart Data.
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More than 70% of eukaryotic proteins are regulated by phosphorylation. However, the mechanism of dephosphorylation that counteracts phosphorylation is less studied. Phosphatases are classified into 104 distinct groups based on substrate-specific features and the sequence homologies in their catalytic domains. Among them, dual-specificity phosphatases (DUSPs) that dephosphorylate both phosphoserine/threonine and phosphotyrosine are important for cellular homeostasis. Ssu72 is a newly studied phosphatase with dual specificity that can dephosphorylate both phosphoserine/threonine and phosphotyrosine. It is important for cell-growth signaling, metabolism, and immune activation. Ssu72 was initially identified as a phosphatase for the Ser5 and Ser7 residues of the C-terminal domain of RNA polymerase II. It prefers the cis configuration of the serine-proline motif within its substrate and regulates Pin1, different from other phosphatases. It has recently been reported that Ssu72 can regulate sister chromatid cohesion and the separation of duplicated chromosomes during the cell cycle. Furthermore, Ssu72 appears to be involved in the regulation of T cell receptor signaling, telomere regulation, and even hepatocyte homeostasis in response to a variety of stress and damage signals. In this review, we aim to summarize various functions of the Ssu72 phosphatase, their implications in diseases, and potential therapeutic indications.
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Fosfoproteínas Fosfatasas/metabolismo , ARN Polimerasa II/metabolismo , Transducción de Señal , Animales , Cromátides/genética , Cromátides/metabolismo , Cromosomas Humanos/genética , Cromosomas Humanos/metabolismo , Humanos , Peptidilprolil Isomerasa de Interacción con NIMA/metabolismo , Fosfoproteínas Fosfatasas/genética , Dominios Proteicos , ARN Polimerasa II/genética , Receptores de Antígenos de Linfocitos T/genética , Receptores de Antígenos de Linfocitos T/metabolismoRESUMEN
Cold-adapted bacteria primarily have two glucose 6-phosphate dehydrogenase isozymes (G6PD, also known as zwf), zwf-1 for the Entner-Doudoroff pathway and zwf-2 for the oxidative pentose phosphate pathway. Although the roles of zwfs in carbon metabolism and antioxidant defense have been reported, the biochemical properties of zwfs at low and moderate temperatures have not been fully described. In this study, we cloned and characterized zwf-1 (Pmzwf-1) and zwf-2 (Pmzwf-2) from a cold-adapted bacterium Pseudomonas mandelii JR-1. Pmzwf-1 and Pmzwf-2 were expressed in Escherichia coli BL21 (DE3) as soluble tetrameric proteins. Both Pmzwf proteins were active at 4 °C, but Pmzwf-1 exhibited overall better biochemical properties than those of Pmzwf-2, including 10-30% higher specific activity at 4-40 °C as well as consistent conformational flexibility and thermal stability in the 4-40 °C range. Pmzwf-2 showed reduced thermal stability at moderate temperatures. Furthermore, the mRNA expression of Pmzwf-1 was higher than that of Pmzwf-2 at both 4 °C and 25 °C. These results indicate that Pmzwfs are cold-adapted enzymes, but Pmzwf-1 can function at both low to moderate temperatures while Pmzwf-2 is primarily functional at low temperatures. Our results suggest distinct temperature adaptations of two G6PD isozymes in P. mandelii JR-1, adaptations that are metabolic pathway dependent.
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Pseudomonas , Glucosa , Glucosafosfato Deshidrogenasa , Isoenzimas , FosfatosRESUMEN
The ventral subiculum (vSub) is the major output structure of the hippocampus and serves as a main limbic region in mediating the brain's response to stress. Previously, we reported that there are three subtypes of vSub neurons based on their firing patterns: regular-spiking (RS), weak-bursting (WB) and strong-bursting (SB) neurons and chronic social defeat stress (CSDS) increased SB neurons especially in the proximal vSub. Here, we found that neurons in the proximal vSub projected to the nucleus accumbens (NAc). CSDS significantly increased SB neurons but decreased RS neurons among the NAc-projecting vSub neuronal population. Interestingly, these changes were only apparent in mice susceptible to CSDS, but not in CSDS-resilient ones. Given that ventral hippocampal inputs to the NAc regulate susceptibility to CSDS, the bursting activity of NAc-projecting vSub neurons might be functionally relevant to behavioral susceptibility to CSDS.
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Potenciales de Acción , Neuronas/patología , Núcleo Accumbens/fisiopatología , Conducta Social , Estrés Psicológico/fisiopatología , Animales , Reacción de Prevención , Susceptibilidad a Enfermedades , Relaciones Interpersonales , Masculino , Ratones Endogámicos C57BLRESUMEN
The ventral subiculum (vSub), a representative output structure of the hippocampus, serves as a main limbic region in mediating the brain's response to stress. There are three subtypes of subicular pyramidal neurons based on their firing patterns: regular-spiking (RS), weak-bursting (WB) and strong-bursting (SB) neurons, located differently along proximal-distal axis. Here, we found that chronic social defeat stress (CSDS) in mice increased the population of SB neurons but decreased RS neurons in the proximal vSub. Specific blockers of T-type calcium channels inhibited the burst firings with a concomitant reduction of afterdepolarization, suggesting that T-type calcium channels underlie the burst-spiking activity. Consistently, CSDS increased both T-type calcium currents and expression of Cav3.1 proteins, a subtype of T-type calcium channels, in the proximal vSub. Therefore, we conclude that CSDS-induced enhancement of Cav3.1 expression increased bursting neuronal population in the vSub, which may contribute to stress-related behaviors.
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Potenciales de Acción/fisiología , Canales de Calcio Tipo T/metabolismo , Hipocampo/fisiopatología , Neuronas/fisiología , Conducta Social , Estrés Psicológico/metabolismo , Estrés Psicológico/fisiopatología , Potenciales de Acción/efectos de los fármacos , Animales , Bloqueadores de los Canales de Calcio/farmacología , Enfermedad Crónica , Hipocampo/efectos de los fármacos , Masculino , Ratones Endogámicos C57BL , Neuronas/efectos de los fármacosRESUMEN
An ionic interaction that holds an α-helix and a ß-strand on which catalytic Asp and His residues are located, respectively, is conserved in a hyperthermophilic esterase EstE1 (optimum temperature 70 °C) and a mesophilic esterase rPPE (optimum temperature 50 °C). We investigated the role of an ionic interaction between E258 and R275 in EstE1 and that between E263 and R280 in rPPE in active-site stability of serine esterases adapted to different temperatures. Ala substitutions caused a 5-10 °C decrease in the optimum temperature of both EstE1 and rPPE mutants. Surprisingly, disruption of the ionic interaction caused larger effects on the conformational flexibility of EstE1 mutants despite their rigid structures, whereas the disruption had fewer effects on the thermal stability of EstE1 mutants at 60-70 °C, as the structure of EstE1 was adapted to high temperatures. In contrast, mesophilic rPPE mutants showed dramatic decreases in thermal stability at 40-50 °C, but less changes in conformational flexibility because of their inherently flexible structures. The results of this study suggest that the ionic interaction between the α-helix with catalytic Asp and the ß-strand with catalytic His plays an important role in the active-site conformation of EstE1 and rPPE, with larger effects on the conformational flexibility of hyperthermophilic EstE1 and the thermal stability of mesophilic rPPE.
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Esterasas , Estructura Secundaria de Proteína , Pseudomonas , Proteínas Bacterianas/química , Proteínas Bacterianas/genética , Catálisis , Esterasas/química , Esterasas/genética , Pseudomonas/enzimología , Pseudomonas/genéticaRESUMEN
Glucose 6-phosphate dehydrogenase (G6PD) (EC 1.1.1.363) is a crucial regulatory enzyme in the oxidative pentose phosphate pathway that provides reductive potential in the form of NADPH, as well as carbon skeletons for the synthesis of macromolecules. In this study, we report the cloning, expression, and characterization of G6PD (SpG6PD1) from a lichen-associated psychrophilic bacterium Sphingomonas sp. PAMC 26621. SpG6PD1 was expressed in Escherichia coli as a soluble protein, having optimum activity at pH 7.5â»8.5 and 30 °C for NADP⺠and 20 °C for NADâº. SpG6PD1 utilized both NADP⺠and NADâº, with the preferential utilization of NADPâº. A high Km value for glucose 6-phosphate and low activation enthalpy (ΔH) compared with the values of mesophilic counterparts indicate the psychrophilic nature of SpG6PD1. Despite the secondary structure of SpG6PD1 being maintained between 4â»40 °C, its activity and tertiary structure were better preserved between 4â»20 °C. The results of this study indicate that the SpG6PD1 that has a flexible structure is most suited to a psychrophilic bacterium that is adapted to a permanently cold habitat.