Background: Glutamate gated postsynaptic receptors in the central nervous system (CNS) are essential for environmentally stimulated behaviours including learning and memory in both invertebrates and vertebrates. Though their genetics, biochemistry, physiology, and role in behaviour have been intensely studied in vitro and in vivo, their molecular evolution and structural aspects remain poorly understood. To understand how these receptors have evolved different physiological requirements we have investigated the molecular evolution of glutamate gated receptors and ion channels, in particular the N-methyl-D-aspartate (NMDA) receptor, which is essential for higher cognitive function. Studies of rodent NMDA receptors show that the C-terminal intracellular domain forms a signalling complex with enzymes and scaffold proteins, which is important for neuronal and behavioural plasticity
Results: The vertebrate NMDA receptor was found to have subunits with C-terminal domains up to 500 amino acids longer than invertebrates. This extension was specific to the NR2 subunit and occurred before the duplication and subsequent divergence of NR2 in the vertebrate lineage. The shorter invertebrate C-terminus lacked vertebrate protein interaction motifs involved with forming a signaling complex although the terminal PDZ interaction domain was conserved. The vertebrate NR2 C-terminal domain was predicted to be intrinsically disordered but with a conserved secondary structure.
Conclusion: We highlight an evolutionary adaptation specific to vertebrate NMDA receptor NR2 subunits. Using in silico methods we find that evolution has shaped the NMDA receptor C-terminus into an unstructured but modular intracellular domain that parallels the expansion in complexity of an NMDA receptor signalling complex in the vertebrate lineage. We propose the NR2 C-terminus has evolved to be a natively unstructured yet flexible hub organising postsynaptic signalling. The evolution of the NR2 C-terminus and its associated signalling complex may contribute to species differences in behaviour and in particular cognitive function.
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http://dx.doi.org/10.1186/1471-2202-9-6 | DOI Listing |
Int J Mol Sci
January 2025
Department of Pathology, Faculty of Health Care and Social Work, Trnava University and University Hospital, 917 02 Trnava, Slovakia.
The autoantibodies against the NR1 subunit are well known in the pathomechanism of NMDAR encephalitis. The dysfunction of the NR2 subunit could be a critical factor in this neurological disorder due to its important role in the postsynaptic pathways that direct synaptic plasticity. We report a case of paraneoplastic anti-NMDAR encephalitis presented alongside very severe illness.
View Article and Find Full Text PDFBiomedicines
December 2024
Department of Oral Biology, Semmelweis University, H-1089 Budapest, Hungary.
Background: N-methyl-D-aspartate type glutamate receptors (NMDARs) are fundamental to neuronal physiology and pathophysiology. The prefrontal cortex (PFC), a key region for cognitive function, is heavily implicated in neuropsychiatric disorders, positioning the modulation of its glutamatergic neurotransmission as a promising therapeutic target. Our recently published findings indicate that AT receptor activation enhances NMDAR activity in layer V pyramidal neurons of the rat PFC.
View Article and Find Full Text PDFAntioxidants (Basel)
January 2025
Division of Molecular Medicine, Ruđer Bošković Institute, 10000 Zagreb, Croatia.
Although commonly appreciated for their anti-oxidative and neuroprotective properties, flavonoids can also exhibit pro-oxidative activity, potentially reducing cell survival, particularly in the presence of metal ions. Disrupted copper homeostasis is a known contributor to neuronal dysfunction through oxidative stress induction. This study investigated the effects of myricitrin (1-20 μg/mL) on copper-induced toxicity (0.
View Article and Find Full Text PDFNeurobiol Dis
January 2025
Division of Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, Canada. Electronic address:
The consequences of non-pathogenic huntingtin (HTT) reduction in the mature brain are of substantial importance as clinical trials for numerous HTT-lowering therapies are underway; many of which are non-selective in that they reduce both mutant and wild type protein variants. In this study, we injected CaMKII-promoted AAV-Cre directly into the hippocampus of adult HTT floxed mice to explore the role of wild-type huntingtin (wtHTT) in adult hippocampal pyramidal neurons and the broader implications of its loss. Our findings reveal that wtHTT depletion results in profound macroscopic morphological abnormalities in hippocampal structure, accompanied by significant reactive gliosis.
View Article and Find Full Text PDFCell
January 2025
University of Chinese Academy of Sciences, Beijing, China; Institute of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai 200031, China. Electronic address:
The cerebral cortex and hippocampus are crucial brain regions for learning and memory, which depend on activity-induced synaptic plasticity involving N-methyl-ᴅ-aspartate receptors (NMDARs). However, subunit assembly and molecular architecture of endogenous NMDARs (eNMDARs) in the brain remain elusive. Using conformation- and subunit-dependent antibodies, we purified eNMDARs from adult rat cerebral cortex and hippocampus.
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