ABSTRACT
This corrects the article DOI: 10.1038/ncomms14907.
ABSTRACT
Planar cell polarity (PCP) signaling is well known to play a critical role during prenatal brain development; whether it plays specific roles at postnatal stages remains rather unknown. Here, we investigated the role of a key PCP-associated gene scrib in CA1 hippocampal structure and function at postnatal stages. We found that Scrib is required for learning and memory consolidation in the Morris water maze as well as synaptic maturation and NMDAR-dependent bidirectional plasticity. Furthermore, we unveiled a direct molecular interaction between Scrib and PP1/PP2A phosphatases whose levels were decreased in postsynaptic density of conditional knock-out mice. Remarkably, exposure to enriched environment (EE) preserved memory formation in CaMK-Scrib-/- mice by recovering synaptic plasticity and maturation. Thus, Scrib is required for synaptic function involved in memory formation and EE has beneficiary therapeutic effects. Our results demonstrate a distinct new role for a PCP-associated protein, beyond embryonic development, in cognitive functions during adulthood.
Subject(s)
Cognitive Dysfunction/physiopathology , Cognitive Dysfunction/therapy , Environment , Intracellular Signaling Peptides and Proteins/deficiency , Neuronal Plasticity/physiology , Animals , COS Cells , Chlorocebus aethiops , Cognitive Dysfunction/pathology , Hippocampus/growth & development , Hippocampus/metabolism , Hippocampus/ultrastructure , Housing, Animal , Intracellular Signaling Peptides and Proteins/genetics , Learning Disabilities/pathology , Learning Disabilities/physiopathology , Learning Disabilities/therapy , Male , Memory Disorders/pathology , Memory Disorders/physiopathology , Memory Disorders/therapy , Mice, Knockout , Models, Molecular , Post-Synaptic Density/metabolism , Post-Synaptic Density/ultrastructure , Receptors, N-Methyl-D-Aspartate/metabolism , Synapses/metabolism , Synapses/ultrastructureABSTRACT
Mutations in GPSM2 cause Chudley-McCullough syndrome (CMCS), an autosomal recessive neurological disorder characterized by early-onset sensorineural deafness and brain anomalies. Here, we show that mutation of the mouse orthologue of GPSM2 affects actin-rich stereocilia elongation in auditory and vestibular hair cells, causing deafness and balance defects. The G-protein subunit Gαi3, a well-documented partner of Gpsm2, participates in the elongation process, and its absence also causes hearing deficits. We show that Gpsm2 defines an â¼200 nm nanodomain at the tips of stereocilia and this localization requires the presence of Gαi3, myosin 15 and whirlin. Using single-molecule tracking, we report that loss of Gpsm2 leads to decreased outgrowth and a disruption of actin dynamics in neuronal growth cones. Our results elucidate the aetiology of CMCS and highlight a new molecular role for Gpsm2/Gαi3 in the regulation of actin dynamics in epithelial and neuronal tissues.
Subject(s)
Actins/metabolism , Agenesis of Corpus Callosum/genetics , Arachnoid Cysts/genetics , Carrier Proteins/genetics , Growth Cones/metabolism , Hair Cells, Auditory/metabolism , Hair Cells, Vestibular/metabolism , Hearing Loss, Sensorineural/genetics , Neurons/metabolism , Stereocilia/metabolism , Agenesis of Corpus Callosum/metabolism , Agenesis of Corpus Callosum/physiopathology , Animals , Arachnoid Cysts/metabolism , Arachnoid Cysts/physiopathology , Cell Cycle Proteins , Deafness/genetics , GTP-Binding Protein alpha Subunits, Gi-Go/metabolism , Hearing Loss, Sensorineural/metabolism , Hearing Loss, Sensorineural/physiopathology , Intracellular Signaling Peptides and Proteins/genetics , Membrane Proteins/metabolism , Mice , Mutation , Myosins/metabolism , Postural Balance , Sensation Disorders/geneticsABSTRACT
A major gap of knowledge in metalloproteins is the identity of the prefolded state of the protein before cofactor insertion. This holds for molybdoenzymes serving multiple purposes for life, especially in energy harvesting. This large group of prokaryotic enzymes allows for coordination of molybdenum or tungsten cofactors (Mo/W-bisPGD) and Fe/S clusters. Here we report the structural data on a cofactor-less enzyme, the nitrate reductase respiratory complex and characterize the conformational changes accompanying Mo/W-bisPGD and Fe/S cofactors insertion. Identified conformational changes are shown to be essential for recognition of the dedicated chaperone involved in cofactors insertion. A solvent-exposed salt bridge is shown to play a key role in enzyme folding after cofactors insertion. Furthermore, this salt bridge is shown to be strictly conserved within this prokaryotic molybdoenzyme family as deduced from a phylogenetic analysis issued from 3D structure-guided multiple sequence alignment. A biochemical analysis with a distantly-related member of the family, respiratory complex I, confirmed the critical importance of the salt bridge for folding. Overall, our results point to a conserved cofactors insertion mechanism within the Mo/W-bisPGD family.
Subject(s)
Metalloproteins/metabolism , Molybdenum/metabolism , Nitrate Reductase/metabolism , Amino Acid Sequence , Metalloproteins/chemistry , Nitrate Reductase/chemistry , Oxidation-Reduction , Protein Folding , Scattering, Small Angle , Sequence Homology, Amino Acid , X-Ray DiffractionABSTRACT
The appropriate trafficking of glutamate receptors to synapses is crucial for basic synaptic function and synaptic plasticity. It is now accepted that NMDA receptors (NMDARs) internalize and are recycled at the plasma membrane but also exchange between synaptic and extrasynaptic pools; these NMDAR properties are also key to governing synaptic plasticity. Scribble1 is a large PDZ protein required for synaptogenesis and synaptic plasticity. Herein, we show that the level of Scribble1 is regulated in an activity-dependent manner and that Scribble1 controls the number of NMDARs at the plasma membrane. Notably, Scribble1 prevents GluN2A subunits from undergoing lysosomal trafficking and degradation by increasing their recycling to the plasma membrane following NMDAR activation. Finally, we show that a specific YxxR motif on Scribble1 controls these mechanisms through a direct interaction with AP2. Altogether, our findings define a molecular mechanism to control the levels of synaptic NMDARs via Scribble1 complex signaling.
