Graphene Quantum Dots Attenuate TDP-43 Proteinopathy in Amyotrophic Lateral Sclerosis.

Aberrant phase separation- and stress granule (SG)-mediated cytosolic aggregation of TDP-43 in motor neurons is the hallmark of amyotrophic lateral sclerosis (ALS). In this study, we found that graphene quantum dots (GQDs) potentially modulate TDP-43 aggregation during SG dynamics and phase separation. The intrinsically disordered region in the C-terminus of TDP-43 exhibited amyloid fibril formation; however, GQDs inhibited the formation of amyloid fibrils through direct intermolecular interactions with TDP-43.

[Biological phase separation in neuromuscular diseases].

Biological phase separation refers to the liquid-liquid phase separation of biomolecules such as proteins in cells. Phase separation is driven by low-complexity domains of phase-separating proteins and strictly controlled by regulatory factors. Phase separation has also been found to be disrupted by genetic abnormalities.

Mutation-driven evolution of antibacterial function in an ancestral antifungal scaffold: Significance for peptide engineering.

Mutation-driven evolution of novel function on an old gene has been documented in many development- and adaptive immunity-related genes but is poorly understood in immune effector molecules. Drosomycin-type antifungal peptides (DTAFPs) are a family of defensin-type effectors found in plants and ecdysozoans. Their primitive function was to control fungal infection and then co-opted for fighting against bacterial infection in plants, insects, and nematodes.

-Derived Proline:Arginine Poly-Dipeptides Modulate Cytoskeleton and Mechanical Stress Response.

Proline:arginine (PR) poly-dipeptides from the GGGGCC repeat expansion in have cytotoxicity and bind intermediate filaments (IFs). However, it remains unknown how PR poly-dipeptides affect cytoskeletal organization and focal adhesion (FA) formation. Here, we show that changes to the cytoskeleton and FA by PR poly-dipeptides result in the alteration of cell stiffness and mechanical stress response.

Red-Beet Betalain Pigments Inhibit Amyloid-β Aggregation and Toxicity in Amyloid-β Expressing Caenorhabditis elegans.

Betalain pigments are mainly produced by plants belonging to the order of Caryophyllales. Betalains exhibit strong antioxidant activity and responds to environmental stimuli and stress in plants. Recent reports of antioxidant, anti-inflammatory and anti-cancer properties of betalain pigments have piqued interest in understanding their biological functions.

Simple But Efficacious Enrichment of Integral Membrane Proteins and Their Interactions for In-Depth Membrane Proteomics.

Membrane proteins play essential roles in various cellular processes, such as nutrient transport, bioenergetic processes, cell adhesion, and signal transduction. Proteomics is one of the key approaches to exploring membrane proteins comprehensively. Bottom-up proteomics using LC-MS/MS has been widely used in membrane proteomics.

Quick and Mild Isolation of Intact Lysosomes Using Magnetic-Plasmonic Hybrid Nanoparticles.

Rapid and efficient isolation of intact lysosomes is necessary to study their functions and metabolites by proteomic analysis. We developed a swift and robust nanoparticle-based magnetic separation method in which magnetic-plasmonic hybrid nanoparticles (MPNPs) conjugated with amino dextran (aDxt) were targeted to the lumen of lysosomes the endocytosis pathway. For well-directed magnetic separation of the lysosomes, it is important to trace the intracellular trafficking of the aDxt-conjugated MPNPs (aDxt-MPNPs) in the endocytosis pathway.

Fungal effector SIB1 of Colletotrichum orbiculare has unique structural features and can suppress plant immunity in Nicotiana benthamiana.

Fungal plant pathogens secrete virulence-related proteins, called effectors, to establish host infection; however, the details are not fully understood yet. Functional screening of effector candidates using Agrobacterium-mediated transient expression assay in Nicotiana benthamiana identified two virulence-related effectors, named SIB1 and SIB2 (Suppression of Immunity in N. benthamiana), of an anthracnose fungus Colletotrichum orbiculare, which infects both cucurbits and N.

Evolution-Based Protein Engineering for Antifungal Peptide Improvement.

Antimicrobial peptides (AMPs) have been considered as the alternatives to antibiotics because of their less susceptibility to microbial resistance. However, compared with conventional antibiotics they show relatively low activity and the consequent high cost and nonspecific cytotoxicity, hindering their clinical application. What's more, engineering of AMPs is a great challenge due to the inherent complexity in their sequence, structure, and function relationships.

Structure and antimicrobial activity of NCR169, a nodule-specific cysteine-rich peptide of Medicago truncatula.

A model legume, Medicago truncatula, has over 600 nodule-specific cysteine-rich (NCR) peptides required for symbiosis with rhizobia. Among them, NCR169, an essential factor for establishing symbiosis, has four cysteine residues that are indispensable for its function. However, knowledge of NCR169 structure and mechanism of action is still lacking.

Production of ORF8 protein from SARS-CoV-2 using an inducible virus-mediated expression system in suspension-cultured tobacco BY-2 cells.

Production of ORF8 protein from SARS-CoV-2 in tobacco BY-2 cells.

Met872 is the key residue determining the novel binominal binding of metabotropic glutamate receptor 7 to calmodulin.

Two mGluR7-derived peptides corresponding to residues 856 to 879 and 856 to 875 are known to bind to Ca-saturated calmodulin (Ca/CaM), and their binding manners are thought to differ. Met872 function is believed as one of the anchor residues for CaM-binding only in the shorter peptide. To uncover the role of Met872 in CaM-binding, we prepared a mutant of the long peptide, mGluR7 (M872A), in which Met872 was replaced with Ala.

Ca-dependent interaction between calmodulin and CoDN3, an effector of Colletotrichum orbiculare.

Nuclear magnetic resonance (NMR) data directly indicated a Ca-dependent interaction between calmodulin (CaM) and CoDN3, a small effector of the plant pathogenic fungus Colletotrichum orbiculare, which is the causal agent of cucumber anthracnose. The overall conformation of CoDN3 is intrinsically disordered, and the CaM-binding site spans residues 34-53 of its C-terminal region. Experiments employing a chemically synthesized peptide corresponding to the CaM-binding site indicated that the CaM-binding region of CoDN3 in the Ca-bound CaM complex takes an α-helical conformation.

Isolation of amaranthin synthetase from Chenopodium quinoa and construction of an amaranthin production system using suspension-cultured tobacco BY-2 cells.

Betalains are plant pigments primarily produced by plants of the order Caryophyllales. Because betalain possesses anti-inflammatory and anticancer activities, it may be useful as a pharmaceutical agent and dietary supplement. Recent studies have identified the genes involved in the betalain biosynthesis of betanin.

Impairment of the carnitine/organic cation transporter 1-ergothioneine axis is mediated by intestinal transporter dysfunction in chronic kidney disease.

Carnitine/organic cation transporter 1 (OCTN1) is a specific transporter of the food-derived antioxidant ergothioneine. Ergothioneine is absorbed by intestinal OCTN1, distributed through the bloodstream, and incorporated into each organ by OCTN1. OCTN1 expression is upregulated in injured tissues, and promotes ergothioneine uptake to reduce further damage caused by oxidative stress.

Utilization of Liver Microsomes to Estimate Hepatic Intrinsic Clearance of Monoamine Oxidase Substrate Drugs in Humans.

Purpose: Monoamine oxidases (MAOs) are non-CYP enzymes that contribute to systemic elimination of therapeutic agents, and localized on mitochondrial membranes. The aim of the present study was to validate quantitative estimation of metabolic clearance of MAO substrate drugs using human liver microsomes (HLMs).

Methods: Three MAO substrate drugs, sumatriptan, rizatriptan and phenylephrine, as well as four CYP substrates were selected, and their disappearance during incubation with HLMs or mitochondria (HLMt) was measured.

Increased Dynamics of Tricarboxylic Acid Cycle and Glutamate Synthesis in Obese Adipose Tissue: IN VIVO METABOLIC TURNOVER ANALYSIS.

Obesity is closely associated with various metabolic disorders. However, little is known about abnormalities in the metabolic change of obese adipose tissue. Here we use static metabolic analysis and metabolic turnover analysis to assess metabolic dynamics in obese mice.

Molecular architecture of the stria vascularis membrane transport system, which is essential for physiological functions of the mammalian cochlea.

Stria vascularis of the mammalian cochlea transports K(+) to establish the electrochemical property in the endolymph crucial for hearing. This epithelial tissue also transports various small molecules. To clarify the profile of proteins participating in the transport system in the stria vascularis, membrane components purified from the stria of adult rats were analysed by liquid chromatography tandem mass spectrometry.

Unique structural changes in calcium-bound calmodulin upon interaction with protein 4.1R FERM domain: novel insights into the calcium-dependent regulation of 4.1R FERM domain binding to membrane proteins by calmodulin.

Calmodulin (CaM) binds to the FERM domain of 80 kDa erythrocyte protein 4.1R (R30) independently of Ca(2+) but, paradoxically, regulates R30 binding to transmembrane proteins in a Ca(2+)-dependent manner. We have previously mapped a Ca(2+)-independent CaM-binding site, pep11 (A(264)KKLWKVCVEHHTFFR), in 4.

Novel mechanism of regulation of protein 4.1G binding properties through Ca2+/calmodulin-mediated structural changes.

Protein 4.1G (4.1G) is a widely expressed member of the protein 4.

Hypervalent nonbonded interactions of a divalent sulfur atom. Implications in protein architecture and the functions.

In organic molecules a divalent sulfur atom sometimes adopts weak coordination to a proximate heteroatom (X). Such hypervalent nonbonded S···X interactions can control the molecular structure and chemical reactivity of organic molecules, as well as their assembly and packing in the solid state. In the last decade, similar hypervalent interactions have been demonstrated by statistical database analysis to be present in protein structures.

Conformation of the calmodulin-binding domain of metabotropic glutamate receptor subtype 7 and its interaction with calmodulin.

Calmodulin (CaM), a Ca(2+)-binding protein, is a well-known regulator of various cellular functions. One of the targets of CaM is metabotropic glutamate receptor 7 (mGluR7), which serves as a low-pass filter for glutamate in the pre-synaptic terminal to regulate neurotransmission. Surface plasmon resonance (SPR), circular dichroism (CD) spectroscopy and nuclear magnetic spectroscopy (NMR) were performed to study the structure of the peptides corresponding to the CaM-binding domain of mGluR7 and their interaction with CaM.

Expression and purification of metabotropic glutamate receptor 7 peptides.

Metabotropic glutamate receptors (mGluRs) influence a variety of second-messenger systems and ion channels. The C-terminal region of group III mGluRs interacts with the Ca(2+)-binding protein calmodulin (CaM). We intend to study the interaction between Ca(2+)/CaM and the CaM-binding motifs within mGluR(7), which is a group III mGluR.

Phosphorylation-induced conformational switching of CPI-17 produces a potent myosin phosphatase inhibitor.

Phosphorylation of endogenous inhibitor proteins for type-1 Ser/Thr phosphatase (PP1) provides a mechanism for reciprocal coordination of kinase and phosphatase activities. A myosin phosphatase inhibitor protein CPI-17 is phosphorylated at Thr38 through G-protein-mediated signals, resulting in a >1000-fold increase in inhibitory potency. We show here the solution NMR structure of phospho-T38-CPI-17 with rmsd of 0.