TY  - JOUR
A1  - Salehi, Saeede
A1  - Zare, Abdolhossein
A1  - Prezza, Gianluca
A1  - Bader, Jakob
A1  - Schneider, Cornelius
A1  - Fischer, Utz
A1  - Meissner, Felix
A1  - Mann, Matthias
A1  - Briese, Michael
A1  - Sendtner, Michael
T1  - Cytosolic Ptbp2 modulates axon growth in motoneurons through axonal localization and translation of Hnrnpr
JF  - Nature Communications
N2  - The neuronal RNA-binding protein Ptbp2 regulates neuronal differentiation by modulating alternative splicing programs in the nucleus. Such programs contribute to axonogenesis by adjusting the levels of protein isoforms involved in axon growth and branching. While its functions in alternative splicing have been described in detail, cytosolic roles of Ptbp2 for axon growth have remained elusive. Here, we show that Ptbp2 is located in the cytosol including axons and growth cones of motoneurons, and that depletion of cytosolic Ptbp2 affects axon growth. We identify Ptbp2 as a major interactor of the 3’ UTR of Hnrnpr mRNA encoding the RNA-binding protein hnRNP R. Axonal localization of Hnrnpr mRNA and local synthesis of hnRNP R protein are strongly reduced when Ptbp2 is depleted, leading to defective axon growth. Ptbp2 regulates hnRNP R translation by mediating the association of Hnrnpr with ribosomes in a manner dependent on the translation factor eIF5A2. Our data thus suggest a mechanism whereby cytosolic Ptbp2 modulates axon growth by fine-tuning the mRNA transport and local synthesis of an RNA-binding protein.
KW  - molecular neuroscience
KW  - RNA-binding proteins
KW  - RNA transport
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-357639
VL  - 14
ER  - 
TY  - JOUR
A1  - Rajab, Suhaila
A1  - Bismin, Leah
A1  - Schwarze, Simone
A1  - Pinggera, Alexandra
A1  - Greger, Ingo H.
A1  - Neuweiler, Hannes
T1  - Allosteric coupling of sub-millisecond clamshell motions in ionotropic glutamate receptor ligand-binding domains
JF  - Communications Biology
N2  - Ionotropic glutamate receptors (iGluRs) mediate signal transmission in the brain and are important drug targets. Structural studies show snapshots of iGluRs, which provide a mechanistic understanding of gating, yet the rapid motions driving the receptor machinery are largely elusive. Here we detect kinetics of conformational change of isolated clamshell-shaped ligand-binding domains (LBDs) from the three major iGluR sub-types, which initiate gating upon binding of agonists. We design fluorescence probes to measure domain motions through nanosecond fluorescence correlation spectroscopy. We observe a broad kinetic spectrum of LBD dynamics that underlie activation of iGluRs. Microsecond clamshell motions slow upon dimerization and freeze upon binding of full and partial agonists. We uncover allosteric coupling within NMDA LBD hetero-dimers, where binding of L-glutamate to the GluN2A LBD stalls clamshell motions of the glycine-binding GluN1 LBD. Our results reveal rapid LBD dynamics across iGluRs and suggest a mechanism of negative allosteric cooperativity in NMDA receptors.
KW  - fluorescence spectroscopy
KW  - kinetics
KW  - ligand-gated ion channels
KW  - molecular neuroscience
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-261678
VL  - 4
IS  - 1
ER  - 
TY  - JOUR
A1  - Mitjans, M.
A1  - Begemann, M.
A1  - Ju, A.
A1  - Dere, E.
A1  - Wüstefeld, L.
A1  - Hofer, S.
A1  - Hassouna, I.
A1  - Balkenhol, J.
A1  - Oliveira, B.
A1  - Van der Auwera, S.
A1  - Tammer, R.
A1  - Hammerschmidt, K.
A1  - Völzke, H.
A1  - Homuth, G.
A1  - Cecconi, F.
A1  - Chowdhury, K.
A1  - Grabe, H.
A1  - Frahm, J.
A1  - Boretius, S.
A1  - Dandekar, T.
A1  - Ehrenreich, H.
T1  - Sexual dimorphism of \(AMBRA1\)-related autistic features in human and mouse
JF  - Translational Psychiatry
N2  - \(Ambra1\) is linked to autophagy and neurodevelopment. Heterozygous \(Ambra1\) deficiency induces autism-like behavior in a sexually dimorphic manner. Extraordinarily, autistic features are seen in female mice only, combined with stronger Ambra1 protein reduction in brain compared to males. However, significance of \(AMBRA1\) for autistic phenotypes in humans and, apart from behavior, for other autism-typical features, namely early brain enlargement or increased seizure propensity, has remained unexplored. Here we show in two independent human samples that a single normal \(AMBRA1\) genotype, the intronic SNP rs3802890-AA, is associated with autistic features in women, who also display lower \(AMBRA1\) mRNA expression in peripheral blood mononuclear cells relative to female GG carriers. Located within a non-coding RNA, likely relevant for mRNA and protein interaction, rs3802890 (A versus G allele) may affect its stability through modification of folding, as predicted by \(in\) \(silico\) analysis. Searching for further autism-relevant characteristics in \(Ambra1^{+/−}\) mice, we observe reduced interest of female but not male mutants regarding pheromone signals of the respective other gender in the social intellicage set-up. Moreover, altered pentylentetrazol-induced seizure propensity, an \(in\) \(vivo\) readout of neuronal excitation–inhibition dysbalance, becomes obvious exclusively in female mutants. Magnetic resonance imaging reveals mild prepubertal brain enlargement in both genders, uncoupling enhanced brain dimensions from the primarily female expression of all other autistic phenotypes investigated here. These data support a role of \(AMBRA1/Ambra1\) partial loss-of-function genotypes for female autistic traits. Moreover, they suggest \(Ambra1\) heterozygous mice as a novel multifaceted and construct-valid genetic mouse model for female autism.
KW  - biology
KW  - clinical genetics
KW  - molecular neuroscience
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-173782
VL  - 2017
IS  - 7
ER  -