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Frontiers in Cellular and Infection... 2020Outer membrane vesicles (OMVs) are nanoscale proteoliposomes secreted from the cell envelope of all Gram-negative bacteria. Originally considered as an artifact of the... (Review)
Review
Outer membrane vesicles (OMVs) are nanoscale proteoliposomes secreted from the cell envelope of all Gram-negative bacteria. Originally considered as an artifact of the cell wall, OMVs are now recognized as a general secretion system, which serves to improve the fitness of bacteria and facilitate bacterial interactions in polymicrobial communities as well as interactions between the microbe and the host. In general, OMVs are released in increased amounts from pathogenic bacteria and have been found to harbor much of the contents of the parental bacterium. They mainly encompass components of the outer membrane and the periplasm including various virulence factors such as toxins, adhesins, and immunomodulatory molecules. Numerous studies have clearly shown that the delivery of toxins and other virulence factors via OMVs essentially influences their interactions with host cells. Here, we review the OMV-mediated intracellular deployment of toxins and other virulence factors with a special focus on intestinal pathogenic . Especially, OMVs ubiquitously produced and secreted by enterohemorrhagic (EHEC) appear as a highly advanced mechanism for secretion and simultaneous, coordinated and direct delivery of bacterial virulence factors into host cells. OMV-associated virulence factors are not only stabilized by the association with OMVs, but can also often target previously unknown target structures and perform novel activities. The toxins are released by OMVs in their active forms and are transported via cell sorting processes to their specific cell compartments, where they can develop their detrimental effects. OMVs can be considered as bacterial "long distance weapons" that attack host tissues and help bacterial pathogens to establish the colonization of their biological niche(s), impair host cell function, and modulate the defense of the host. Thus, OMVs contribute significantly to the virulence of the pathogenic bacteria.
Topics: Animals; Bacterial Outer Membrane; Bacterial Secretion Systems; Bacterial Toxins; Enterohemorrhagic Escherichia coli; Enterotoxigenic Escherichia coli; Enterotoxins; Escherichia coli Infections; Humans; Intestines; Protein Transport; Proteolipids; Stress, Physiological; Virulence; Virulence Factors
PubMed: 32211344
DOI: 10.3389/fcimb.2020.00091 -
International Journal of Molecular... Aug 2021The sarco-endoplasmic reticulum calcium ATPase (SERCA) is responsible for maintaining calcium homeostasis in all eukaryotic cells by actively transporting calcium from... (Review)
Review
The sarco-endoplasmic reticulum calcium ATPase (SERCA) is responsible for maintaining calcium homeostasis in all eukaryotic cells by actively transporting calcium from the cytosol into the sarco-endoplasmic reticulum (SR/ER) lumen. Calcium is an important signaling ion, and the activity of SERCA is critical for a variety of cellular processes such as muscle contraction, neuronal activity, and energy metabolism. SERCA is regulated by several small transmembrane peptide subunits that are collectively known as the "regulins". Phospholamban (PLN) and sarcolipin (SLN) are the original and most extensively studied members of the regulin family. PLN and SLN inhibit the calcium transport properties of SERCA and they are required for the proper functioning of cardiac and skeletal muscles, respectively. Myoregulin (MLN), dwarf open reading frame (DWORF), endoregulin (ELN), and another-regulin (ALN) are newly discovered tissue-specific regulators of SERCA. Herein, we compare the functional properties of the regulin family of SERCA transmembrane peptide subunits and consider their regulatory mechanisms in the context of the physiological and pathophysiological roles of these peptides. We present new functional data for human MLN, ELN, and ALN, demonstrating that they are inhibitors of SERCA with distinct functional consequences. Molecular modeling and molecular dynamics simulations of SERCA in complex with the transmembrane domains of MLN and ALN provide insights into how differential binding to the so-called inhibitory groove of SERCA-formed by transmembrane helices M2, M6, and M9-can result in distinct functional outcomes.
Topics: Animals; Calcium; Calcium-Binding Proteins; Humans; Models, Molecular; Muscle Proteins; Proteolipids; Sarcoplasmic Reticulum Calcium-Transporting ATPases
PubMed: 34445594
DOI: 10.3390/ijms22168891 -
Progress in Lipid Research Jan 2019To study membrane fusion mediated by synaptic proteins, proteoliposomes have been widely used for in vitro ensemble measurements with limited insights into the fusion... (Review)
Review
To study membrane fusion mediated by synaptic proteins, proteoliposomes have been widely used for in vitro ensemble measurements with limited insights into the fusion mechanism. Single-particle techniques have proven to be powerful in overcoming the limitations of traditional ensemble methods. Here, we summarize current single-particle methods in biophysical and biochemical studies of fusion mediated by soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) and other synaptic proteins, together with their advantages and limitations.
Topics: Fluorescence Resonance Energy Transfer; Membrane Fusion; Membrane Lipids; Microscopy, Fluorescence; Proteolipids; SNARE Proteins; Single Molecule Imaging; Synaptic Transmission; Synaptic Vesicles
PubMed: 30611882
DOI: 10.1016/j.plipres.2019.01.001 -
Bioengineered Jan 2018The need for cost-effectively produced and improved biocatalysts for industrial, pharmaceutical and environmental processes is steadily increasing. While enzyme... (Review)
Review
The need for cost-effectively produced and improved biocatalysts for industrial, pharmaceutical and environmental processes is steadily increasing. While enzyme properties themselves can be improved via protein engineering, immobilization by attachment to carrier materials remains a critical step for stabilization and process implementation. A new emerging immobilization approach, the in situ immobilization, enables simultaneous production of highly active enzymes and carrier materials using bioengineering/synthetic biology of microbial cells. In situ enzyme immobilization holds the promise of cost-effective production of highly functional immobilized biocatalysts for uses such as in bioremediation, drug synthesis, bioenergy and food processing.
Topics: Adsorption; Biocatalysis; Biodegradation, Environmental; Cross-Linking Reagents; Enzymes, Immobilized; Food Handling; Gene Expression; Inclusion Bodies; Magnetosomes; Polyhydroxyalkanoates; Protein Engineering; Proteolipids; Recombinant Fusion Proteins
PubMed: 28463573
DOI: 10.1080/21655979.2017.1325040 -
Nature Sep 2020Mutations in PLP1, the gene that encodes proteolipid protein (PLP), result in failure of myelination and neurological dysfunction in the X-chromosome-linked...
Mutations in PLP1, the gene that encodes proteolipid protein (PLP), result in failure of myelination and neurological dysfunction in the X-chromosome-linked leukodystrophy Pelizaeus-Merzbacher disease (PMD). Most PLP1 mutations, including point mutations and supernumerary copy variants, lead to severe and fatal disease. Patients who lack PLP1 expression, and Plp1-null mice, can display comparatively mild phenotypes, suggesting that PLP1 suppression might provide a general therapeutic strategy for PMD. Here we show, using CRISPR-Cas9 to suppress Plp1 expression in the jimpy (Plp1) point-mutation mouse model of severe PMD, increased myelination and restored nerve conduction velocity, motor function and lifespan of the mice to wild-type levels. To evaluate the translational potential of this strategy, we identified antisense oligonucleotides that stably decrease the levels of Plp1 mRNA and PLP protein throughout the neuraxis in vivo. Administration of a single dose of Plp1-targeting antisense oligonucleotides in postnatal jimpy mice fully restored oligodendrocyte numbers, increased myelination, improved motor performance, normalized respiratory function and extended lifespan up to an eight-month end point. These results suggest that PLP1 suppression could be developed as a treatment for PMD in humans. More broadly, we demonstrate that oligonucleotide-based therapeutic agents can be delivered to oligodendrocytes in vivo to modulate neurological function and lifespan, establishing a new pharmaceutical modality for myelin disorders.
Topics: Animals; CRISPR-Cas Systems; Disease Models, Animal; Female; Gene Editing; Hypoxia; Male; Mice; Mice, Mutant Strains; Motor Activity; Myelin Proteolipid Protein; Myelin Sheath; Oligodendroglia; Oligonucleotides, Antisense; Pelizaeus-Merzbacher Disease; Point Mutation; Respiratory Function Tests; Survival Analysis
PubMed: 32610343
DOI: 10.1038/s41586-020-2494-3 -
Theranostics 2021Estrogen-dependent cancers (e.g., breast, endometrial, and ovarian cancers) are among the leading causes of morbidity and mortality in women worldwide. Recently,...
Estrogen-dependent cancers (e.g., breast, endometrial, and ovarian cancers) are among the leading causes of morbidity and mortality in women worldwide. Recently, exosomes released by tumor-infiltrating CD8 T cells have been under the spotlight in the field of cancer immunotherapy. Our study aims at elucidating the underlying mechanisms of the crosstalk between estrogen signaling and CD8 T cells, and possible intervention values in uterine corpus endometrial cancer (UCEC). Micro RNA-seq was conducted to screen differentially expressed micro RNA in UCEC. Bioinformatic analysis was processed to predict the target of miR-765. RNA silencing or overexpressing and pharmacologic inhibitors were used to assess the functions of ERβ/miR-765/PLP2/Notch axis in UCEC cell proliferation and invasion and . imaging was performed to evaluate the metastasis of tumor in mice. Combined fluorescent hybridization for miR-765 and immunofluorescent labeling for CD8 was carried out to prove the co-localization between miR-765 and CD8 T cells. Exosomes derived from CD45ROCD8 T cells were isolated to detect the regulatory effects on UCEC. miR-765 is characterized as the most downregulated miRNA in UCEC, and there is a negative correlation between miR-765 and Proteolipid protein 2 (PLP2) in UCEC lesion. Estrogen significantly down-regulates miR-765 level, and facilitates the development of UCEC by estrogen receptor (ER) β. Mechanistically, this process is mediated through the miRNAs (e.g., miR-3584-5p, miR-7-5p, miR-150-5p, and miR-124-3p) cluster-controlled regulation of the PLP2, which further regulates Ki-67 and multiple epithelial-mesenchymal transition (EMT)-related molecules (e.g, E-cadherin and Vimentin) in a Notch signaling pathway-dependent manner. Interestingly, the selective ER degrader Fulvestrant alleviates estrogen-mediated miR-765/PLP2 expression regulation and UCEC development in ERβ-dependent and -independent manners. Additionally, CD45ROCD8 T cell-derived exosomes release more miR-765 than that from CD45ROCD8 T cells. In therapeutic studies, these exosomes limit estrogen-driven disease development via regulation of the miR-765/PLP2 axis. This observation reveals novel molecular mechanisms underlying estrogen signaling and CD8 T cell-released exosomes in UCEC development, and provides a potential therapeutic strategy for UCEC patients with aberrant ERβ/miR-765/PLP2/Notch signaling axis.
Topics: Adult; Animals; CD8-Positive T-Lymphocytes; Cadherins; Cell Proliferation; Cells, Cultured; Down-Regulation; Endometrial Neoplasms; Epithelial-Mesenchymal Transition; Estrogen Receptor beta; Estrogens; Exosomes; Female; Humans; Leukocyte Common Antigens; MARVEL Domain-Containing Proteins; Mice; Mice, Nude; MicroRNAs; Middle Aged; Proteolipids; RNA Interference; Receptors, Notch; Signal Transduction
PubMed: 33859750
DOI: 10.7150/thno.58337 -
Proceedings of the National Academy of... Nov 2017EmrE is a small multidrug resistance transporter found in that confers resistance to toxic polyaromatic cations due to its proton-coupled antiport of these substrates....
EmrE is a small multidrug resistance transporter found in that confers resistance to toxic polyaromatic cations due to its proton-coupled antiport of these substrates. Here we show that EmrE breaks the rules generally deemed essential for coupled antiport. NMR spectra reveal that EmrE can simultaneously bind and cotransport proton and drug. The functional consequence of this finding is an exceptionally promiscuous transporter: not only can EmrE export diverse drug substrates, it can couple antiport of a drug to either one or two protons, performing both electrogenic and electroneutral transport of a single substrate. We present a free-exchange model for EmrE antiport that is consistent with these results and recapitulates ∆pH-driven concentrative drug uptake. Kinetic modeling suggests that free exchange by EmrE sacrifices coupling efficiency but boosts initial transport speed and drug release rate, which may facilitate efficient multidrug efflux.
Topics: Antiporters; Binding Sites; Biological Transport; Dicyclohexylcarbodiimide; Drug Resistance, Multiple, Bacterial; Escherichia coli; Escherichia coli Proteins; Gene Expression; Hydrogen-Ion Concentration; Kinetics; Molecular Dynamics Simulation; Onium Compounds; Organophosphorus Compounds; Phosphatidylcholines; Phosphatidylglycerols; Protein Binding; Protein Interaction Domains and Motifs; Protein Structure, Secondary; Proteolipids; Protons; Recombinant Proteins; Substrate Specificity; Thermodynamics; Xenobiotics
PubMed: 29114048
DOI: 10.1073/pnas.1708671114 -
Biochimica Et Biophysica Acta Jan 2015The motional averaging of powder pattern line shapes is one of the most fundamental aspects of sold-state NMR. Since membrane proteins in liquid crystalline phospholipid... (Review)
Review
The motional averaging of powder pattern line shapes is one of the most fundamental aspects of sold-state NMR. Since membrane proteins in liquid crystalline phospholipid bilayers undergo fast rotational diffusion, all of the signals reflect the angles of the principal axes of their dipole-dipole and chemical shift tensors with respect to the axis defined by the bilayer normal. The frequency span and sign of the axially symmetric powder patterns that result from motional averaging about a common axis provide sufficient structural restraints for the calculation of the three-dimensional structure of a membrane protein in a phospholipid bilayer environment. The method is referred to as rotationally aligned (RA) solid-state NMR and demonstrated with results on full-length, unmodified membrane proteins with one, two, and seven trans-membrane helices. RA solid-state NMR is complementary to other solid-state NMR methods, in particular oriented sample (OS) solid-state NMR of stationary, aligned samples. Structural distortions of membrane proteins from the truncations of terminal residues and other sequence modifications, and the use of detergent micelles instead of phospholipid bilayers have also been demonstrated. Thus, it is highly advantageous to determine the structures of unmodified membrane proteins in liquid crystalline phospholipid bilayers under physiological conditions. RA solid-state NMR provides a general method for obtaining accurate and precise structures of membrane proteins under near-native conditions.
Topics: Amino Acid Sequence; Diffusion; Magnetic Resonance Spectroscopy; Membrane Proteins; Molecular Sequence Data; Protein Folding; Proteolipids; Rotation
PubMed: 24747039
DOI: 10.1016/j.bbamem.2014.04.002 -
ACS Applied Bio Materials Jan 2021Multiple sclerosis is complex and heterogeneous. Better tools are needed to be able to monitor this disease among individuals, but blood-based biomarkers are often too...
Multiple sclerosis is complex and heterogeneous. Better tools are needed to be able to monitor this disease among individuals, but blood-based biomarkers are often too rare to profile. In this work, we developed antigen-specific biomaterials to replicate the central nervous system niche where multiple sclerosis biomarkers are amplified. We incorporated mouse brain homogenate into a microporous gelatin methacrylate network. Homogenate-containing biomaterials differentially stimulated cells and led to the marked amplification of disease-relevant, antigen-specific B cells. These results demonstrate that biomaterials containing primary tissue homogenate retain antigen specificity and may be a useful tool for decoding human autoimmunity.
Topics: Animals; Antigens; Autoimmunity; B-Lymphocytes; B7-2 Antigen; Biocompatible Materials; Brain; Encephalomyelitis, Autoimmune, Experimental; Gelatin; Mice; Myelin Proteolipid Protein; Peptide Fragments; Spleen
PubMed: 35014289
DOI: 10.1021/acsabm.0c01048 -
Neuroscience Letters Mar 2019Hibernation in mammals is a whole-body phenotype that involves profound reductions in oxygen consumption, metabolic reactions, core body temperature, neural activity and... (Review)
Review
Hibernation in mammals is a whole-body phenotype that involves profound reductions in oxygen consumption, metabolic reactions, core body temperature, neural activity and heart rate. An important aspect of mammalian hibernation is the ability to reverse this state of hypothermic torpor by rewarming and subsequent arousal. Brown adipose tissue (BAT) and skeletal muscle shivering have been characterized as the predominant driving forces for thermogenesis during arousal. Conversely, the thermogenic contribution of these organs needs to be minimized as hibernating mammals enter torpor. Because skeletal muscle accounts for approximately 40% of the dry mass of the typical mammalian body, we aim to broaden the spotlight to include the importance of down-regulating skeletal muscle non-shivering thermogenesis during hibernation to allow for whole-body cooling and long-term maintenance of a depressed core body temperature when the animal is in torpor. This minireview will briefly describe the current understanding of thermoregulation in hibernating mammals and present new preliminary data on the importance of skeletal muscle and the micro-peptide sarcolipin as a major thermogenic target.
Topics: Animals; Down-Regulation; Hibernation; Hot Temperature; Humans; Hypothermia; Muscle Proteins; Muscle, Skeletal; Proteolipids
PubMed: 30528880
DOI: 10.1016/j.neulet.2018.11.059