7 research outputs found
AMPA Receptors Commandeer an Ancient Cargo Exporter for Use as an Auxiliary Subunit for Signaling
Fast excitatory neurotransmission in the mammalian central nervous system is mainly mediated by ionotropic glutamate receptors of the AMPA subtype (AMPARs). AMPARs are protein complexes of the pore-lining α-subunits GluA1-4 and auxiliary ÎČ-subunits modulating their trafficking and gating. By a proteomic approach, two homologues of the cargo exporter cornichon, CNIH-2 and CNIH-3, have recently been identified as constituents of native AMPARs in mammalian brain. In heterologous reconstitution experiments, CNIH-2 promotes surface expression of GluAs and modulates their biophysical properties. However, its relevance in native AMPAR physiology remains controversial. Here, we have studied the role of CNIH-2 in GluA processing both in heterologous cells and primary rat neurons. Our data demonstrate that CNIH-2 serves an evolutionarily conserved role as a cargo exporter from the endoplasmic reticulum (ER). CNIH-2 cycles continuously between ER and Golgi complex to pick up cargo protein in the ER and then to mediate its preferential export in a coat protein complex (COP) II dependent manner. Interaction with GluA subunits breaks with this ancestral role of CNIH-2 confined to the early secretory pathway. While still taking advantage of being exported preferentially from the ER, GluAs recruit CNIH-2 to the cell surface. Thus, mammalian AMPARs commandeer CNIH-2 for use as a bona fide auxiliary subunit that is able to modify receptor signaling
The Cannabinoid Receptor CB1 Interacts with the WAVE1 Complex and Plays a Role in Actin Dynamics and Structural Plasticity in Neurons
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The Polarimetric and Helioseismic Imager on Solar Orbiter
This paper describes the Polarimetric and Helioseismic Imager on the Solar
Orbiter mission (SO/PHI), the first magnetograph and helioseismology instrument
to observe the Sun from outside the Sun-Earth line. It is the key instrument
meant to address the top-level science question: How does the solar dynamo work
and drive connections between the Sun and the heliosphere? SO/PHI will also
play an important role in answering the other top-level science questions of
Solar Orbiter, as well as hosting the potential of a rich return in further
science.
SO/PHI measures the Zeeman effect and the Doppler shift in the FeI 617.3nm
spectral line. To this end, the instrument carries out narrow-band imaging
spectro-polarimetry using a tunable LiNbO_3 Fabry-Perot etalon, while the
polarisation modulation is done with liquid crystal variable retarders (LCVRs).
The line and the nearby continuum are sampled at six wavelength points and the
data are recorded by a 2kx2k CMOS detector. To save valuable telemetry, the raw
data are reduced on board, including being inverted under the assumption of a
Milne-Eddington atmosphere, although simpler reduction methods are also
available on board. SO/PHI is composed of two telescopes; one, the Full Disc
Telescope (FDT), covers the full solar disc at all phases of the orbit, while
the other, the High Resolution Telescope (HRT), can resolve structures as small
as 200km on the Sun at closest perihelion. The high heat load generated through
proximity to the Sun is greatly reduced by the multilayer-coated entrance
windows to the two telescopes that allow less than 4% of the total sunlight to
enter the instrument, most of it in a narrow wavelength band around the chosen
spectral line
The Polarimetric and Helioseismic Imager on Solar Orbiter
Aims. This paper describes the Polarimetric and Helioseismic Imager on the Solar Orbiter mission (SO/PHI), the first magnetograph and helioseismology instrument to observe the Sun from outside the Sun-Earth line. It is the key instrument meant to address the top-level science question: How does the solar dynamo work and drive connections between the Sun and the heliosphere? SO/PHI will also play an important role in answering the other top-level science questions of Solar Orbiter, while hosting the potential of a rich return in further science.
Methods. SO/PHI measures the Zeeman effect and the Doppler shift in the FeâŻ