Transmembrane Signaling Research Articles

Mechanistic Insights Into Redox Damage of the Podocyte in Hypertension.

Podocytes are specialized cells within the glomerular filtration barrier, which are crucial for maintaining glomerular structural integrity and convective ultrafiltration. Podocytes exhibit a unique arborized morphology with foot processes interfacing by slit diaphragms, ladder-like, multimolecular sieves, which provide size and charge selectivity for ultrafiltration and transmembrane signaling. Podocyte dysfunction, resulting from oxidative stress, dysregulated prosurvival signaling, or structural damage, can drive the development of proteinuria and glomerulosclerosis in hypertensive nephropathy. Functionally, podocyte injury leads to actin cytoskeleton rearrangement, foot process effacement, dysregulated slit diaphragm protein expression, and impaired ultrafiltration. Notably, the renin-angiotensin system plays a pivotal role in podocyte function, with beneficial AT2R (angiotensin receptor 2)-mediated nitric oxide (NO) signaling to counteract AT1R (angiotensin receptor 1)-driven calcium (Ca2+) influx and oxidative stress. Disruption of this balance contributes significantly to podocyte dysfunction and drives albuminuria, a marker of kidney damage and overall disease progression. Oxidative stress can also lead to sustained ion channel-mediated Ca2+ influx and precipitate cytoskeletal disorganization. The complex interplay between GPCR signaling, ion channel activation, and redox injury pathways underscores the need for additional research aimed at identifying targeted therapies to protect podocytes and preserve glomerular function. Earlier detection of albuminuria and podocyte injury through routine noninvasive diagnostics will also be critical in populations at the highest risk for the development of hypertensive kidney disease. In this review, we highlight the established mechanisms of oxidative stress-mediated podocyte damage in proteinuric kidney diseases, with an emphasis on a hypertensive renal injury. We will also consider emerging therapies that have the potential to selectively protect podocytes from redox-related injury.

Oriented triplex DNA as a synthetic receptor for transmembrane signal transduction.

Signal transduction across biological membranes enables cells to detect and respond to diverse chemical or physical signals, and replicating these complex biological processes through synthetic methods is of significant interest in synthetic biology. Here we present an artificial signal transduction system using oriented cholesterol-tagged triplex DNA (TD) as synthetic receptors to transmit and amplify signals across lipid bilayer membranes through H+-mediated TD conformational transitions from duplex to triplex. An auxiliary sequence, complementary to the third strand of the TD, ensures a controlled and preferred outward orientation of cholesterol-tagged TD on membranes. Upon external H+ stimuli, the conformational change triggers the translocation of the third strand from the outer to the inner membrane leaflet, resulting in effective transmembrane signal transduction. This mechanism enables fluorescence resonance energy transfer (FRET), selective photocleavage, catalytic signal amplification, and logic gate modulation within vesicles. Our findings demonstrate that these TD-based receptors mimic the functional dynamics of natural G protein-coupled receptors (GPCRs), providing a foundation for advanced applications in biosensing, cell signaling modulation, and targeted drug delivery systems.

N-glycosylation facilitates the activation of a plant cell-surface receptor.

Plant receptor kinases (RKs) are critical for transmembrane signalling involved in various biological processes including plant immunity. MALE DISCOVERER1-INTERACTING RECEPTOR-LIKE KINASE 2 (MIK2) is a unique RK that recognizes a family of immunomodulatory peptides called SERINE-RICH ENDOGENOUS PEPTIDEs (SCOOPs) and activates pattern-triggered immunity responses. However, the precise mechanisms underlying SCOOP recognition and activation of MIK2 remain poorly understood. Here we present the cryogenic electron microscopy structure of a ternary complex consisting of the extracellular leucine-rich repeat (LRR) of MIK2 (MIK2LRR), SCOOP12 and the extracellular LRR of the co-receptor BAK1 (BAK1LRR) at a resolution of 3.34 Å. The structure reveals that a DNHH motif in MIK2LRR plays a critical role in specifically recognizing the highly conserved SxS motif of SCOOP12. Furthermore, the structure demonstrates that N-glycans at MIK2LRRAsn410 directly interact with the N-terminal capping region of BAK1LRR. Mutation of the glycosylation site, MIK2LRRN410D, completely abolishes the SCOOP12-independent interaction between MIK2LRR and BAK1LRR and substantially impairs the assembly of the MIK2LRR-SCOOP12-BAK1LRR complex. Supporting the biological relevance of N410-glycosylation, MIK2N410D substantially compromises SCOOP12-triggered immune responses in plants. Collectively, these findings elucidate the mechanism underlying the loose specificity of SCOOP recognition by MIK2 and reveal an unprecedented mechanism by which N-glycosylation modification of LRR-RK promotes receptor activation.

TYROBP promotes the spread of pancreatic cancer by causing M2 TAM polarization.

M2-polarized tumor-associated macrophages (M2 TAMs) are known to promote cancer progression, and exosomes are crucial mediators of communication within the tumor microenvironment (TME). However, the specific role of exosomes derived from M2 TAMs in pancreatic cancer (PC) progression remains poorly understood. Tyrosine kinase binding protein (TYROBP, also known as DAP12 for DNAX activating protein-12) is a transmembrane signal transduction polypeptide that interacts with immune cell receptors, influencing cellular functions via signal transduction pathways. TYROBP is prominently found in M2 TAMs exosomes, facilitating its transfer to PC cells and suggesting a potential role in PC pathogenesis. This study initially confirmed the presence of TYROBP in M2 TAMs exosomes and its transfer to PC cells via exosomes. The impact of TYROBP on PC proliferation, apoptosis, migration, and invasion was investigated. Special attention was given to TYROBP's influence on PC metastasis and its underlying mechanisms, focusing particularly on the CD44/AKT/ERK signaling pathway. TYROBP expression in PC cells did not significantly affect tumor cell proliferation or apoptosis but demonstrated a notable inhibitory effect on migration and invasion, which was mediated through the CD44/AKT/ERK pathway. Both in vivo and in vitro experiments consistently showed that TYROBP enhanced PC metastasis. This study elucidates that TYROBP plays a direct role in promoting PC metastasis through its association with M2 TAMs polarization. Therefore, TYROBP represents a potential novel therapeutic target for interventions aimed at combatting PC progression.

Structural basis for the transmembrane signaling and antidepressant-induced activation of the receptor tyrosine kinase TrkB.

Neurotrophin receptors of the Trk family are involved in the regulation of brain development and neuroplasticity, and therefore can serve as targets for anti-cancer and stroke-recovery drugs, antidepressants, and many others. The structures of Trk protein domains in various states upon activation need to be elucidated to allow rational drug design. However, little is known about the conformations of the transmembrane and juxtamembrane domains of Trk receptors. In the present study, we employ NMR spectroscopy to solve the structure of the TrkB dimeric transmembrane domain in the lipid environment. We verify the structure using mutagenesis and confirm that the conformation corresponds to the active state of the receptor. Subsequent study of TrkB interaction with the antidepressant drug fluoxetine, and the antipsychotic drug chlorpromazine, provides a clear self-consistent model, describing the mechanism by which fluoxetine activates the receptor by binding to its transmembrane domain.

Structural Basis for Chemerin Recognition and Signaling Through Its Receptors

Chemerin is a chemotactic adipokine that participates in a multitude of physiological processes, including adipogenesis, leukocyte chemotaxis, and neuroinflammation. Chemerin exerts biological functions through binding to one or more of its G protein-coupled receptors (GPCRs), namely chemokine-like receptor 1 (CMKLR1), G protein-coupled receptor 1 (GPR1), and CC-motif receptor-like 2 (CCRL2). Of these receptors, CMKLR1 and GPR1 have been confirmed as signaling receptors of chemerin, whereas CCRL2 serves as a chemerin-binding protein without transmembrane signaling. High-resolution structures of two chemerin receptors are now available thanks to recent advancements in structure biology. This review focuses on the structural perspectives of the chemerin receptors with an emphasis on the structure–activity correlation, including key components of the two receptors for ligand recognition and conformational changes induced by chemerin and its derivative peptides for G protein activation. There are also comparisons between the two chemerin receptors and selected GPCRs with peptide ligands for better appreciation of the shared and distinct features of the chemerin receptors in ligand recognition and transmembrane signaling, and in the evolution of this subclass of GPCRs.

Suppression of epithelial proliferation and tumourigenesis by immunoglobulin A.

Immunoglobulin A (IgA) is the most abundant antibody isotype produced across mammals and plays a specialized role in mucosal homeostasis 1 . Constantly secreted into the lumen of the intestine, IgA binds commensal microbiota to regulate their colonization and function 2,3 with unclear implications for health. IgA deficiency is common in humans but is difficult to study due to its complex aetiology and comorbidities 4-8 . Using genetically and environmentally controlled mice, here we show that IgA-deficient animals have increased susceptibility to endogenous colorectal tumours. Cellular and molecular analyses revealed that, in the absence of IgA, colonic epithelial cells induce antibacterial factors and accelerate cell cycling in response to the microbiota. Oral treatment with IgA was sufficient to both reduce steady-state proliferation and protect mice from tumours, but this function was due to antibody structure rather than binding specificity. In both organoid and monolayer culture systems, IgA directly suppressed epithelial growth. Co-immunoprecipitation mass spectrometry and a targeted CRISPR screen identified DMBT1 as an IgA-binding epithelial surface protein required for IgA-mediated suppression of proliferation. Together, IgA and DMBT1 regulate Notch signalling and tune the normal cycling of absorptive colonocyte progenitors. In mice, deleting the transmembrane and cytoplasmic signalling portions of DMBT1 or blocking Notch signalling was sufficient to reverse both the increased proliferation and tumour susceptibility of IgA knockouts. These experiments establish a homeostatic function for IgA in tempering physiological epithelial responses to microbiota to maintain mucosal health.

Computational Evaluation of Bioactive Compounds in Vernonia Amygdalina as a Novel Therapeutics for Acute Myeloid Leukemia: Targeting the Hedgehog Pathway

AbstractThe drug resistance challenges in acute myeloid leukemia have been linked the hedgehog (HH) signaling pathway activation by many studies. Furthermore, studies have shown that the components of the HH pathway, including 12‐pass transmembrane receptor Patched (PTCH), the 7‐pass transmembrane signal transduction protein Smoothened (SMO), and all three GLI transcription factors, are expressed in AML. Thus, pharmacological inhibition of SMO in the HH signaling in these cells has anti‐leukemic effects. However, the first SMO inhibitor specific to AML (Glasdegib) has been approved based on improved overall survival rates, but alternative approaches are still required. Thus we employed druglikeness screening, molecular docking, molecular dynamics simulation, non‐equilibrium free energy and in silico pharmacokinetics profiling on bioactive compounds from Vernonia amygdalina against SMO protein target. From 30 bioactive compounds in V. amygdalina, 13 had drug‐like potential, 5 had binding energy between −9.2 to −9.9 kcal/mol. Cryptolepine, neocryptolepine and isocryptolepine with the least BE showed good stability, dynamics over 300 ns of MD run and higher binding affinities via the Jarzynski's identity. Hence, these bioactive compounds may serve as potential drugs for the treatment of acute myeloid leukemia by targeting the SMO protein after wet lab experiments.

Identification of immunogenic antigens and evaluation of vaccine candidates against Clostridium perfringens

Necrotic enteritis (NE) caused by Clostridium perfringens (C. perfringens) has resulted in significant losses for the poultry industry worldwide. Currently, there is no widely promoted vaccine for NE. In this study, immunoprecipitation (IP) was employed to isolate immunogenic proteins of C. perfringens, and 118 potential candidate antigens were identified through liquid chromatography-mass spectrometry/mass spectrometry (LC–MS/MS). From these, three candidate antigen proteins were selected based on their predicted antigenicity, hydrophilicity, stability, and transmembrane signalling properties: ArcB (an ornithine aminotransferase), TmpC (a probable membrane lipoprotein), and EntB (a possible enterotoxin). These three proteins were successfully produced in large quantities using Escherichia coli (E. coli), with confirmed good solubility. Both in vitro and in vivo research demonstrated that these antigens possess strong immunogenicity, eliciting robust antigen-specific humoral and cellular immune responses in chickens and mitigating NE symptoms caused by C. perfringens. The candidate antigens identified through immunoproteomics hold potential as subunit vaccines against C. perfringens infection.

The Prevalence and Molecular Characterization of Bovine Leukemia Virus among Dairy Cattle in Henan Province, China.

Enzootic bovine leukosis, a neoplastic disease caused by the bovine leukemia virus (BLV), was the primary cancer affecting cattle in China before 1985. Although its prevalence decreased significantly between 1986 and 2000, enzootic bovine leukosis has been re-emerging since 2000. This re-emergence has been largely overlooked, possibly due to the latent nature of BLV infection or the perceived lack of sufficient evidence. This study investigated the molecular epidemiology of BLV infections in dairy cattle in Henan province, Central China. Blood samples from 668 dairy cattle across nine farms were tested using nested polymerase chain reaction assays targeting the partial envelope (env) gene (gp51 fragment). Twenty-three samples tested positive (animal-level prevalence of 3.4%; 95% confidence interval: 2.2, 5.1). The full-length env gene sequences from these positive samples were obtained and phylogenetically analyzed, along with previously reported sequences from the GenBank database. The sequences from positive samples were clustered into four genotypes (1, 4, 6, and 7). The geographical annotation of the maximum clade credibility trees suggested that the two genotype 1 strains in Henan might have originated from Japan, while the genotype 7 strain is likely to have originated from Moldova. Subsequent Bayesian stochastic search variable selection analysis further indicated a strong geographical association between the Henan strains and Japan, as well as Moldova. The estimated substitution rate for the env gene ranged from 4.39 × 10-4 to 2.38 × 10-3 substitutions per site per year. Additionally, codons 291, 326, 385, and 480 were identified as positively selected sites, potentially associated with membrane fusion, epitope peptide vaccine design, and transmembrane signal transduction. These findings contribute to the broader understanding of BLV epidemiology in Chinese dairy cattle and highlight the need for measures to mitigate further BLV transmission within and between cattle herds in China.

Resting human trabecular meshwork cells experience tonic cation influx.

The trabecular meshwork (TM) regulates intraocular pressure (IOP) by converting biochemical and biomechanical stimuli into intracellular signals. Recent electrophysiological studies demonstrated that this process is mediated by pressure sensing ion channels in the TM plasma membrane while the molecular and functional properties of channels that underpin ionic homeostasis in resting cells remain largely unknown. Here, we demonstrate that the TM resting potential is subserved by a powerful cationic conductance that disappears following Na+ removal and substitution with choline or NMDG+. Its insensitivity to TTX, verapamil, phenamil methanesulfonate and amiloride indicates it does not involve voltage-operated Na+, Ca2+ and epithelial Na+ (ENaC) channels or Na+/H+ exchange while a modest hyperpolarization induced by SEA-0440 indicates residual contribution from reversed Na+/Ca2+ exchange. Tonic cationic influx was inhibited by Gd3+ and Ruthenium Red but not GsMTx4, indicating involvement of TRP-like but not Piezo channels. Transcriptional analysis detected expression of most TRP genes, with the canonical transcriptome pool dominated by TRPC1 followed by the expression ofTRPV1, TRPC3 and TRPC5. TRPC3 antagonist Pyr3 and TRPC1,4,5 antagonist Pico1,4,5 did not affect the standing current, whereas the TRPC blocker SKF96365 promoted rather than suppressed, Na+ influx. TM cells thus maintain the resting membrane potential, control Na+ homeostasis, and balance K+ efflux through a novel constitutive monovalent cation leak current with properties not unlike those of TRP channels. Yet to be identified at the molecular level, this novel channel sets the homeostatic steady-state and controls the magnitude of pressure-induced transmembrane signals.

New insights into the role of myo-inositol in regulating the skin immune response of grass carp (Ctenopharyngodon idella)

Myo-inositol (MI) is a crucial constituent of the cell membrane and has a pivotal role to play in transmembrane signal transduction, ion channel regulation, and cell transport. Fish skin is a vital mucosal immune organ, and there are few studies that have examined the effect of MI on fish skin.Therefore, the purpose of this study was to investigate the role of dietary MI in regulating the skin immune response of grass carp (Ctenopharyngodon idella). A total of 540 fish (221.33 ± 0.84 g) were fed six diets containing graded levels of MI (27.0, 137.9, 286.8, 438.6, 587.7, and 737.3 mg/kg) for 10 weeks. When the growth test was complete, a 14-day challenge was conducted with Aeromonas hydrophila in each group. Our results indicated that the most effective MI concentrations (approximately 438.6–737.3 mg/kg diet) resulted in the following outcomes: (1) MI reduced the morbidity of grass carp skin and increased the thickness of the dense dermis layer. (2) MI enhanced the physical barrier function of the skin, maybe via increasing antioxidant capacity, inhibiting apoptosis, and improving tight junction-related signaling pathways (nuclear factor erythroid 2-related factor 2, p38 mitogen-activated protein kinase, and myosin light chain kinase). (3) MI enhanced skin immune barrier function, possibly via regulating anti-inflammatory and pro-inflammatory cytokines, as well as the target of rapamycin (TOR) and nuclear factor kappa B (NFκB) pathways. This study led to the following conclusion based on its findings: the MI supplementation strengthened the fish skin barrier function and protected it against Aeromonas hydrophila. The dietary MI requirement in on-growing grass carp was estimated to be 370.90 mg/kg by a broken-line method analysis of skin morbidity.

(Invited) Cardiac Engineering: Optical Mapping in Cellular Communication

Microfluidic platforms have emerged as valuable tools for replicating the adverse effects of chemotherapy drugs on cardiac and non-cardiac cells in vitro. However, these systems currently fall short of comprehensively capturing the intricate nature of human responses to chemotherapy, necessitating further validation to enhance model accuracy. While innovative chip systems provide insightful means for screening cardiac toxicity, they encounter challenges in addressing individual variations in drug responses and the influence of patient-specific factors.A novel cardiac chip incorporating intracellular electrophysiological techniques was developed to monitor acute hypoxia-induced responses in cardiac cells. Despite its promising potential, the model exhibits limitations inherent to its simplified two-dimensional microfluidic system, warranting additional validation and optimization efforts to enhance physiological relevance and facilitate applications in clinical translation.Moreover, previous research has proposed the formation of functional connections between human neurons and myocardial cells in a microfluidic chip. However, this study primarily focused on one-way connections between neurons and myocardial cells, overlooking the complexities of bidirectional neuro-muscular connections. Consequently, further research is imperative to deepen our understanding of the intricate interactions between neurons and myocardial cells.Optical mapping techniques assessed transmembrane voltage, mitochondrial activity, and calcium signals during electric pacing. These comprehensive assessments aim to advance our understanding of cardiac electrophysiology under drug exposure, providing crucial insights into the intricate responses of cardiac cells to chemotherapy. This research has significant implications for enhancing our understanding of cardiac safety in the context of chemotherapy.

Metabolic engineering of Pseudomonas bharatica CSV86T to degrade Carbaryl (1-naphthyl-N-methylcarbamate) via the salicylate-catechol route.

Pseudomonas bharatica CSV86T displays the unique property of preferential utilization of aromatic compounds over simple carbon sources like glucose and glycerol and their co-metabolism with organic acids. Well-characterized growth conditions, aromatic compound metabolic pathways and their regulation, genome sequence, and advantageous eco-physiological traits (indole acetic acid production, alginate production, fusaric acid resistance, organic sulfur utilization, and siderophore production) make it an ideal host for metabolic engineering. Strain CSV86T was engineered for Carbaryl (1-naphthyl-N-methylcarbamate) degradation via salicylate-catechol route by expression of a Carbaryl hydrolase (CH) and a 1-naphthol 2-hydroxylase (1NH). Additionally, the engineered strain exhibited faster growth on Carbaryl upon expression of the McbT protein (encoded by the mcbT gene, a part of Carbaryl degradation upper operon of Pseudomonas sp. C5pp). Bioinformatic analyses predict McbT to be an outer membrane protein, and Carbaryl-dependent expression suggests its probable role in Carbaryl uptake. Enzyme activity and protein analyses suggested periplasmic localization of CH (carrying transmembrane domain plus signal peptide sequence at the N-terminus) and 1NH, enabling compartmentalization of the pathway. Enzyme activity, whole-cell oxygen uptake, spent media analyses, and qPCR results suggest that the engineered strain preferentially utilizes Carbaryl over glucose. The plasmid-encoded degradation property was stable for 75-90 generations even in the absence of selection pressure (kanamycin or Carbaryl). These results indicate the utility of P. bharatica CSV86T as a potential host for engineering various aromatic compound degradation pathways.IMPORTANCEThe current study describes engineering of Carbaryl metabolic pathway in Pseudomonas bharatica CSV86T. Carbaryl, a naphthalene-derived carbamate pesticide, is known to act as an endocrine disruptor, mutagen, cytotoxin, and carcinogen. Removal of xenobiotics from the environment using bioremediation faces challenges, such as slow degradation rates, instability of the degradation phenotype, and presence of simple carbon sources in the environment. The engineered CSV86-MEC2 overcomes these disadvantages as Carbaryl was degraded preferentially over glucose. Furthermore, the plasmid-borne degradation phenotype is stable, and presence of glucose and organic acids does not repress Carbaryl metabolism in the strain. The study suggests the role of outer membrane protein McbT in Carbaryl transport. This work highlights the suitability of P. bharatica CSV86T as an ideal host for engineering aromatic pollutant degradation pathways.

Unraveling clonal CD8 T cell expansion and identification of essential factors in γ-herpesvirus-induced lymphomagenesis

Alcelaphine gammaherpesvirus 1 (AlHV-1) asymptomatically persists in its natural host, the wildebeest. However, cross-species transmission to cattle results in the induction of an acute and lethal peripheral T cell lymphoma-like disease (PTCL), named malignant catarrhal fever (MCF). Our previous findings demonstrated an essential role for viral genome maintenance in infected CD8+ T lymphocytes but the exact mechanism(s) leading to lymphoproliferation and MCF remained unknown. To decipher how AlHV-1 dysregulates T lymphocytes, we first examined the global phenotypic changes in circulating CD8+ T cells after experimental infection of calves. T cell receptor repertoire together with transcriptomics and epigenomics analyses demonstrated an oligoclonal expansion of infected CD8+ T cells displaying effector and exhaustion gene signatures, including GZMA, GNLY, PD-1, and TOX2 expression. Then, among viral genes expressed in infected CD8+ T cells, we uncovered A10 that encodes a transmembrane signaling protein displaying multiple tyrosine residues, with predicted ITAM and SH3 motifs. Impaired A10 expression did not affect AlHV-1 replication in vitro but rendered AlHV-1 unable to induce MCF. Furthermore, A10 was phosphorylated in T lymphocytes in vitro and affected T cell signaling. Finally, while AlHV-1 mutants expressing mutated forms of A10 devoid of ITAM or SH3 motifs (or both) were able to induce MCF, a recombinant virus expressing a mutated form of A10 unable to phosphorylate its tyrosine residues resulted in the lack of MCF and protected against a wild-type virus challenge. Thus, we could characterize the nature of this γ-herpesvirus-induced PTCL-like disease and identify an essential mechanism explaining its development.

Allosteric activation of the co-receptor BAK1 by the EFR receptor kinase initiates immune signaling.

Transmembrane signaling by plant receptor kinases (RKs) has long been thought to involve reciprocal trans-phosphorylation of their intracellular kinase domains. The fact that many of these are pseudokinase domains, however, suggests that additional mechanisms must govern RK signaling activation. Non-catalytic signaling mechanisms of protein kinase domains have been described in metazoans, but information is scarce for plants. Recently, a non-catalytic function was reported for the leucine-rich repeat (LRR)-RK subfamily XIIa member EFR (elongation factor Tu receptor) and phosphorylation-dependent conformational changes were proposed to regulate signaling of RKs with non-RD kinase domains. Here, using EFR as a model, we describe a non-catalytic activation mechanism for LRR-RKs with non-RD kinase domains. EFR is an active kinase, but a kinase-dead variant retains the ability to enhance catalytic activity of its co-receptor kinase BAK1/SERK3 (brassinosteroid insensitive 1-associated kinase 1/somatic embryogenesis receptor kinase 3). Applying hydrogen-deuterium exchange mass spectrometry (HDX-MS) analysis and designing homology-based intragenic suppressor mutations, we provide evidence that the EFR kinase domain must adopt its active conformation in order to activate BAK1 allosterically, likely by supporting αC-helix positioning in BAK1. Our results suggest a conformational toggle model for signaling, in which BAK1 first phosphorylates EFR in the activation loop to stabilize its active conformation, allowing EFR in turn to allosterically activate BAK1.

Comparative transcriptomics provides insight into molecular mechanisms of zinc tolerance in the ectomycorrhizal fungus Suillus luteus.

Zinc (Zn) is a major soil contaminant and high Zn levels can disrupt growth, survival, and reproduction of fungi. Some fungal species evolved Zn tolerance through cell processes mitigating Zn toxicity, though the genes and detailed mechanisms underlying mycorrhizal fungal Zn tolerance remain unexplored. To fill this gap in knowledge, we investigated the gene expression of Zn tolerance in the ectomycorrhizal fungus Suillus luteus. We found that Zn tolerance in this species is mainly a constitutive trait that can also be environmentally dependent. Zinc tolerance in S. luteus is associated with differences in expression of genes involved in metal exclusion and immobilization, as well as recognition and mitigation of metal-induced oxidative stress. Differentially expressed genes were predicted to be involved in transmembrane transport, metal chelation, oxidoreductase activity, and signal transduction. Some of these genes were previously reported as candidates for S. luteus Zn tolerance, while others are reported here for the first time. Our results contribute to understanding the mechanisms of fungal metal tolerance and pave the way for further research on the role of fungal metal tolerance in mycorrhizal associations.

Characterization of the GGP gene family in potato (Solanum tuberosum L.) and Pepper (Capsicum annuum L.) and its expression analysis under hormonal and abiotic stresses

GDP-l-galactose phosphorylase (GGP) is a key rate-limiting enzyme in plant ascorbic acid synthesis, which plays an important role in plant growth and development as well as stress response. However, the presence of GGP and its function in potato and pepper are not known. In this study, we first identified two GGP genes in each potato and pepper genomes using a genome-wide search approach. We then analyzed their physicochemical properties, conserved domains, protein structures and phylogenetic relationships. Phylogenetic tree analysis revealed that members of the potato and pepper GGP gene families are related to eggplant (Solanum melongena L.), Arabidopsis (Arabidopsis thaliana L.), tobacco (Nicotiana tabacum L.) and tomato (Solanum lycopersicum L.), with tomato being the most closely related. The promoter sequences mainly contain homeopathic elements such as light-responsive, hormone-responsive and stress-responsive, with light-responsive elements being the most abundant. By analyzing the structure of the genes, it was found that there is no transmembrane structure or signal peptide in the GGP gene family of potatoes and peppers, and that all of its members are hydrophilic proteins. The expression profiles of different tissues show that StGGP1 has the highest expression levels in leaves, StGGP2 has the highest expression levels in stamens, and CaGGPs have the highest expression levels in the early stages of fruit development (Dev1). It was found that StGGPs and CaGGPs genes showed different response to phytohormones and abiotic stresses. Abscisic acid (ABA) treatment induced the most significant change in the expression of StGGPs, while the expression of CaGGPs showed the most pronounced change under methyl jasmonate (MeJA) treatment. StGGPs responded mainly to dark treatment, whereas CaGGPs responded mainly to NaCl stress. These results provide an important basis for a detailed study about the functions of GGP homologous genes in potato and pepper in response to abiotic stresses.

Expression of CD6 in Aggressive NK/T-cell Neoplasms and Assessment as a Potential Therapeutic Target: A Bone Marrow Pathology Group Study

BackgroundAggressive NK/T-Cell neoplasms are rare hematological malignancies characterized by the abnormal proliferation of NK or NK-like T (NK/T) cells. CD6 is a transmembrane signal transducing receptor involved in lymphocyte activation and differentiation. This study aimed to investigate the CD6 expression in these malignancies and explore the potential of targeting CD6 in these diseases. Materials and MethodsWe conducted a retrospective study with totally 41 cases to investigate the expression of CD6 by immunohistochemistry, including aggressive NK-cell leukemia/lymphoma (ANKLL: N = 10) and extranodal NK/T-cell lymphoma (ENKTL: N = 31). A novel ANKLL model was applied for proof-of-concept functional studies of a CD6 antibody-drug-conjugate (CD6-ADC) both in vitro and in animal trial. ResultsCD6 was expressed in 68.3% (28/41) of cases (70% (7/10) of ANKLL and 67.7% (21/31) of ENKTL). The median overall survival (OS) for ANKLL and ENTKL cases was 1 and 12 months, respectively, with no significant difference in OS based on CD6 expression (p > 0.05, Kaplan-Meier with log-rank test). In vitro exposure of the CCANKL cell line, derived from an ANKL patient, to an anti-CD6ADC resulted in dose dependent induction of apoptosis. Furthermore, CCANKL engraftment in NSG mice could be blocked by treatment with the anti-CD6 ADC. ConclusionTo date, this is the first report to explore the expression of CD6 in ANKLL and ENKTL and confirms its expression in the majority of cases. The in vitro and in vivo data support further investigation of CD6 as a potential therapeutic target in these aggressive NK/T-cell malignancies.

Engineering Mesoscale T Cell Receptor Clustering by Plug-and-Play Nanotools.

Tcell receptor (TCR) clustering and formation of an immune synapse are crucial for TCR signaling. However, limited information is available about these dynamic assemblies and their connection to transmembrane signaling. Here, we controlled TCR clustering via plug-and-play nanotools based on an engineered irreversible conjugation pair and a peptide-loaded major histocompatibility complex (pMHC) molecule to compare receptor assembly in a ligand (pMHC)-induced or ligand-independent manner. A streptavidin-binding peptide displayed in both tools enabled their anchoring in streptavidin-pre-structured matrices. Strikingly, pMHC-induced clustering in the confined regions exhibited higher density and dynamics than the ligand-free approach, indicating that the size and architecture of the pMHC ligand influences TCR assembly. Our approach enables the control of membrane receptor clustering with high specificity and provide the possibility to explore different modalities of receptor activation. This article is protected by copyright. All rights reserved.