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@ARTICLE{Brievac:155270,
author = {Briševac, Dušica and Scholz, Ralf and Du, Dan and
Elagabani, Mohammad Nael and Köhr, Georg and Kornau,
Hans-Christian},
title = {{T}he small {GTP}ase {A}rf6 is dysregulated in a mouse
model for fragile {X} syndrome},
journal = {Journal of neurochemistry},
volume = {157},
number = {3},
issn = {1471-4159},
address = {Oxford},
publisher = {Wiley-Blackwell},
reportid = {DZNE-2021-00550},
pages = {666 - 683},
year = {2021},
abstract = {Fragile X syndrome (FXS), the most common inherited cause
of intellectual disability, results from silencing of the
fragile X mental retardation gene 1 (FMR1). The analyses of
FXS patients’ brain autopsies revealed an increased
density of immature dendritic spines in cortical areas. We
hypothesize that the small GTPase Arf6, an actin regulator
critical for the development of glutamatergic synapses and
dendritic spines, is implicated in FXS. Here, we determined
the fraction of active, GTP-bound Arf6 in cortical neuron
cultures and synaptoneurosomes from Fmr1 knockout mice,
measured actin polymerization in neurons expressing Arf6
mutants with variant GTP- or GDP-binding properties, and
recorded hippocampal long-term depression induced by
metabotropic glutamate receptors (mGluR-LTD) in acute brain
slices. We detected a persistently elevated Arf6 activity, a
loss of Arf6 sensitivity to synaptic stimulation and an
increased Arf6-dependent dendritic actin polymerization in
mature Fmr1 knockout neurons. Similar imbalances in Arf6-GTP
levels and actin filament assembly were caused in wild-type
neurons by RNAi-mediated depletion of the postsynaptic Arf6
guanylate exchange factors IQSEC1 (BRAG2) or IQSEC2 (BRAG1).
Targeted deletion of Iqsec1 in hippocampal neurons of
3-week-old mice interfered with mGluR-LTD in wild-type, but
not in Fmr1 knockout mice. Collectively, these data suggest
an aberrant Arf6 regulation in Fmr1 knockout neurons with
consequences for the actin cytoskeleton, spine morphology,
and synaptic plasticity. Moreover, FXS and syndromes caused
by genetic variants in IQSEC1 and IQSEC2 share intellectual
disabilities and developmental delay as main symptoms.
Therefore, dysregulation of Arf6 may contribute to the
cognitive impairment in FXS.},
keywords = {ADP-Ribosylation Factor 6 / ADP-Ribosylation Factors:
metabolism / Actin Cytoskeleton: metabolism / Animals /
Dendritic Spines: ultrastructure / Fragile X Mental
Retardation Protein: genetics / Fragile X Mental Retardation
Protein: metabolism / Fragile X Syndrome: genetics / Fragile
X Syndrome: metabolism / Guanine Nucleotide Exchange
Factors: genetics / Guanine Nucleotide Exchange Factors:
metabolism / Guanosine Triphosphate: metabolism / Mice /
Mice, Inbred C57BL / Mice, Knockout / Nerve Tissue Proteins:
genetics / Neuronal Plasticity: genetics / Neurons:
metabolism / RNA Interference / Receptors, Metabotropic
Glutamate: metabolism / Synaptosomes: metabolism},
cin = {AG Schmitz 1},
ddc = {610},
cid = {I:(DE-2719)1810004},
pnm = {351 - Brain Function (POF4-351)},
pid = {G:(DE-HGF)POF4-351},
typ = {PUB:(DE-HGF)16},
pubmed = {pmid:33125726},
pubmed = {33125726},
doi = {10.1111/jnc.15230},
url = {https://pub.dzne.de/record/155270},
}