93 research outputs found
Ankyrin G restricts ion channel diffusion at the axonal initial segment before the establishment of the diffusion barrier
Ion channel immobilization by ankyrin G is regulated by casein kinase 2 in immature hippocampal neurons
Specification of the NF-κB transcriptional response by p65 phosphorylation and TNF-induced nuclear translocation of IKKε
Here we investigated the regulation of NF-κB activity by post-translational modifications upon reconstitution of NF-κB p65-deficient cells with the wild-type protein or phosphorylation-defect mutants. Analysis of NF-κB target gene expression showed that p65 phosphorylations alone or in combination function to direct transcription in a highly target gene-specific fashion, a finding discussed here as the NF-κB barcode hypothesis. High-resolution microscopy and surface rendering revealed serine 536 phosphorylated p65 predominantly in the cytosol, while serine 468 phosphorylated p65 mainly localized in nuclear speckles. TNF stimulation resulted in the translocation of the cytosolic p65 kinase IKKε to the nucleus and also to promyelocytic leukemia (PML) nuclear bodies. This inducible IKKε translocation was dependent on p65 phosphorylation and was prevented by the oncogenic PML-RARα fusion protein. Chromatin immunoprecipitation experiments revealed the inducible association of IKKε to the control regions of several NF-κB target genes. In the nucleus, the kinase contributes to the expression of a subset of NF-κB-regulated genes, thus revealing a novel role of IKKε for the control of nuclear NF-κB activity
In vivo assembly of the axon initial segment in motor neurons
International audienceThe axon initial segment (AIS) is responsible for both the modulation of action potentials and the maintenance of neuronal polarity. Yet, the molecular mechanisms controlling its assembly are incompletely understood. Our study in single electroporated motor neurons in mouse embryos revealed that AnkyrinG (AnkG), the AIS master organizer, is undetectable in bipolar migrating motor neurons, but is already expressed at the beginning of axonogenesis at E9.5 and initially distributed homogeneously along the entire growing axon. Then, from E11.5, a stage when AnkG is already apposed to the membrane, as observed by electron microscopy, the protein progressively becomes restricted to the proximal axon. Analysis on the global motor neurons population indicated that Neurofascin follows an identical spatio-temporal distribution, whereas sodium channels and beta 4-spectrin only appear along AnkG(+) segments at E11.5. Early patch-clamp recordings of individual motor neurons indicated that at E12.5 these nascent AISs are already able to generate spikes. Using knock-out mice, we demonstrated that neither beta 4-spectrin nor Neurofascin control the distal-to-proximal restriction of AnkG
Precise measurement of the lifetime at Belle II
We measure the lifetime of the meson using a data sample of 207
fb collected by the Belle II experiment running at the SuperKEKB
asymmetric-energy collider. The lifetime is determined by fitting the
decay-time distribution of a sample of
decays. Our result is \tau^{}_{D^+_s} = (498.7\pm
1.7\,^{+1.1}_{-0.8}) fs, where the first uncertainty is statistical and the
second is systematic. This result is significantly more precise than previous
measurements.Comment: 7 pages, 4 figures, to be submitted to Physical Review Letter
First measurement of as an inclusive test of the anomaly
We measure the tau-to-light-lepton ratio of inclusive -meson branching
fractions , where indicates an electron or muon, and thereby test
the universality of charged-current weak interactions. We select events that
have one fully reconstructed meson and a charged lepton candidate from
of electron-positron collision data collected with the
Belle II detector. We find , in agreement with standard-model expectations. This
is the first direct measurement of
Tests of light-lepton universality in angular asymmetries of decays
We present the first comprehensive tests of light-lepton universality in the
angular distributions of semileptonic \Bz-meson decays to charged spin-1
charmed mesons. We measure five angular-asymmetry observables as functions of
the decay recoil that are sensitive to lepton-universality-violating
contributions. We use events where one neutral \B is fully reconstructed in
\PUpsilonFourS{} \to\B\overline{B} decays in data corresponding to \lumion
integrated luminosity from electron-positron collisions collected with the
\belletwo detector. We find no significant deviation from the standard model
expectations
Measurement of branching fractions and direct asymmetries for and decays at Belle II
We report measurements of the branching fractions and direct
asymmetries of the decays , , , and , and use these for testing the standard
model through an isospin-based sum rule. In addition, we measure the branching
fraction and direct asymmetry of the decay and
the branching fraction of the decay . The data are
collected with the Belle II detector from collisions at the
resonance produced by the SuperKEKB asymmetric-energy collider
and contain bottom-antibottom meson pairs. Signal yields are
determined in two-dimensional fits to background-discriminating variables, and
range from 500 to 3900 decays, depending on the channel. We obtain for the sum rule, in agreement with the standard model
expectation of zero and with a precision comparable to the best existing
determinations
Measurement of asymmetries and branching-fraction ratios for and with using Belle and Belle II data
We measure asymmetries and branching-fraction ratios for and decays with , where
is a superposition of and . We use the full data set of the
Belle experiment, containing pairs, and data from the
Belle~II experiment, containing pairs, both collected
in electron-positron collisions at the resonance. Our results
provide model-independent information on the unitarity triangle angle .Comment: 26 pages, 8 figure
Measurement of the -lepton mass with the Belle~II experiment
We present a measurement of the -lepton mass using a sample of about
175 million events collected with the Belle II
detector at the SuperKEKB collider at a center-of-mass energy of
. This sample corresponds to an integrated
luminosity of . We use the kinematic edge of the
pseudomass distribution in the decay and
measure the mass to be , where the first uncertainty is statistical and the second
systematic. This result is the most precise to date
Measurement of asymmetries in decays with Belle II
We present a measurement of time-dependent rate asymmetries in decays to search for non-standard-model physics in transitions. The data sample is collected with the Belle II
detector at the SuperKEKB asymmetric-energy collider in 2019-2022
and contains bottom-antibottom mesons from
resonance decays. We reconstruct signal events and
extract the charge-parity () violating parameters from a fit to the
distribution of the proper-decay-time difference of the two mesons. The
measured direct and mixing-induced asymmetries are
and , respectively, where the first
uncertainties are statistical and the second are systematic. The results are
compatible with the asymmetries observed in
transitions
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