2,918 research outputs found
Very large G protein-coupled receptor 1 regulates myelin-associated glycoprotein via Gαs/Gαq-mediated protein kinases A/C.
VLGR1 (very large G protein-coupled receptor 1), also known as MASS1 (monogenic audiogenic seizure susceptible 1), is an orphan G protein-coupled receptor that contains a large extracellular N terminus with 35 calcium-binding domains. A truncating mutation in the Mass1 gene causes autosomal recessive, sound-induced seizures in the Frings mouse. However, the function of MASS1 and the mechanism underlying Frings mouse epilepsy are not known. Here, we found that MASS1 protein is enriched in the myelinated regions of the superior and inferior colliculi, critical areas for the initiation and propagation of audiogenic seizures. Using a panel of myelin antibodies, we discovered that myelin-associated glycoprotein (MAG) expression is dramatically decreased in Frings mice. MASS1 inhibits the ubiquitylation of MAG, thus enhancing the stability of this protein, and the calcium-binding domains of MASS1 are essential for this regulation. Furthermore, MASS1 interacts with Gαs/Gαq and activates PKA and PKC in response to extracellular calcium. Suppression of signaling by MASS1 RNAi or a specific inhibitor abrogates MAG up-regulation. We postulate that MASS1 senses extracellular calcium and activates cytosolic PKA/PKC pathways to regulate myelination by means of MAG protein stability in myelin-forming cells of the auditory pathway. Further work is required to determine whether MAG dysregulation is a cause or consequence of audiogenic epilepsy and whether there are other pathways regulated by MASS1
Effects of English Teaching with Interactive Whiteboards in the Elementary English Classrooms
The purpose of the study was to probe the effectiveness of English language teaching through Interactive Whiteboards (IWBs). Three specific factors were probed: (a) the results from immediate test and retention test; (b) students’ perceptions related to the utilization of IWBs; (c) the advantages and disadvantages of the technology-supported instruction. Forty-three students from Grade 3 students in Sahes Elementary School in Taiwan were engaged in either technology-supported group or none technology-supported group. The results revealed that the experimental group through technology-supported instruction significantly outperformed the control group on students’ immediate test and retention test. Moreover, students’ perceptions related to the IWBs indicated that most of them enjoying learning English in the technology-supported classrooms. Finally, the results also showed the advantages and disadvantages through the IWBs instructions. The study revealed that teaching through technology was an effective way to help students in English learning
Ab initio study of the giant ferroelectric distortion and pressure induced spin-state transition in BiCoO3
Using configuration-state-constrained electronic structure calculations based
on the generalized gradient approximation plus Hubbard U method, we sought the
origin of the giant tetragonal ferroelectric distortion in the ambient phase of
the potentially multiferroic material BiCoO3 and identified the nature of the
pressure induced spin-state transition. Our results show that a strong Bi-O
covalency drives the giant ferroelectric distortion, which is further
stabilized by an xy-type orbital ordering of the high-spin (HS) Co3+ ions. For
the orthorhombic phase under 5.8 GPa, we find that a mixed HS and low-spin (LS)
state is more stable than both LS and intermediate-spin (IS) states, and that
the former well accounts for the available experimental results. Thus, we
identify that the pressure induced spin-state transition is via a mixed HS+LS
state, and we predict that the HS-to-LS transition would be complete upon a
large volume decrease of about 20%.Comment: 6 pages, 6 figures, 2 table
MicroRNA-23a promotes myelination in the central nervous system.
Demyelinating disorders including leukodystrophies are devastating conditions that are still in need of better understanding, and both oligodendrocyte differentiation and myelin synthesis pathways are potential avenues for developing treatment. Overexpression of lamin B1 leads to leukodystrophy characterized by demyelination of the central nervous system, and microRNA-23 (miR-23) was found to suppress lamin B1 and enhance oligodendrocyte differentiation in vitro. Here, we demonstrated that miR-23a-overexpressing mice have increased myelin thickness, providing in vivo evidence that miR-23a enhances both oligodendrocyte differentiation and myelin synthesis. Using this mouse model, we explored possible miR-23a targets and revealed that the phosphatase and tensin homologue/phosphatidylinositol trisphosphate kinase/Akt/mammalian target of rapamycin pathway is modulated by miR-23a. Additionally, a long noncoding RNA, 2700046G09Rik, was identified as a miR-23a target and modulates phosphatase and tensin homologue itself in a miR-23a-dependent manner. The data presented here imply a unique role for miR-23a in the coordination of proteins and noncoding RNAs in generating and maintaining healthy myelin
A generic theory for Majorana zero modes in 2D superconductors
It is well known that non-Abelian Majorana zero modes (MZM) harbor at vortex
cores in a topological superconductor, which can be
realized in a 2D spin-orbit coupled system with a single Fermi surface and by
proximity coupling to an -wave superconductor. Here we show that existence
of non-Abelian MZMs is unrelated to the bulk topology of a 2D superconductor,
and propose that such exotic modes can be resulted in much broader range of
superconductors, being topological or trivial. For a generic 2D system with
multiple Fermi surfaces and gapped out by superconducting pairings, we show
that at least a single MZM survives if there are only odd number of Fermi
surfaces of which the corresponding superconducting orders have vortices, and
such MZM is protected by an emergent Chern-Simons invariant, irrespective of
the bulk topology of the superconductor. This result may enrich new
experimental schemes for realizing non-Aelian MZMs. In particular, we propose a
minimal scheme to realize the MZMs in a 2D superconducting Dirac semimetal with
trivial bulk topology, which can be well achieved based on the recent cold atom
experiments.Comment: 5 pages, 3 figures, plus Supplementary Materia
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