Yun-Beom Choi

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Zinc (Zn2+) inhibition of N-methyl-D-aspartate receptor (NMDAR) activity involves both voltage-independent and voltage-dependent components. Recombinant NR1/NR2A and NR1/NR2B receptors exhibit similar voltage-dependent block, but voltage-independent Zn2+ inhibition occurs with much higher affinity for NR1/NR2A than NR1/NR2B receptors (nanomolar versus(More)
Prions are proteins that can assume at least two distinct conformational states, one of which is dominant and self-perpetuating. Previously we found that a translation regulator CPEB from Aplysia, ApCPEB, that stabilizes activity-dependent changes in synaptic efficacy can display prion-like properties in yeast. Here we find that, when exogenously expressed(More)
Neuroligin-1 is a potent trigger for the de novo formation of synaptic connections, and it has recently been suggested that it is required for the maturation of functionally competent excitatory synapses. Despite evidence for the role of neuroligin-1 in specifying excitatory synapses, the underlying molecular mechanisms and physiological consequences that(More)
Neurotrophins control the development and adult plasticity of the vertebrate nervous system. Failure to identify invertebrate neurotrophin orthologs, however, has precluded studies in invertebrate models, limiting our understanding of fundamental aspects of neurotrophin biology and function. We identified a neurotrophin (ApNT) and Trk receptor (ApTrk) in(More)
Until recently cysteine residues, especially those located extracellularly, were thought to be important for metal coordination, catalysis and protein structure by forming disulfide bonds - but they were not thought to regulate protein function. However, this is not the case. Crucial cysteine residues can be involved in modulation of protein activity and(More)
Recent evidence indicates that the NO-related species, nitroxyl anion (NO), is produced in physiological systems by several redox metal-containing proteins, including hemoglobin, nitric oxide synthase (NOS), superoxide dismutase, and S-nitrosothiols (SNOs), which have recently been identified in brain. However, the chemical biology of NO- remains largely(More)
Despite considerable evidence for a critical role of neuroligin-1 in the specification of excitatory synapses, the cellular mechanisms and physiological roles of neuroligin-1 in mature neural circuits are poorly understood. In mutant mice deficient in neuroligin-1, or adult rats in which neuroligin-1 was depleted, we have found that neuroligin-1 stabilizes(More)
Loss of the Fragile X mental retardation protein (FMRP) is associated with presumed postsynaptic deficits in mouse models of Fragile X syndrome. However, the possible presynaptic roles of FMRP in learning-related plasticity have received little attention. As a result, the mechanisms whereby FMRP influences synaptic function remain poorly understood. To(More)
To explore how gene products, required for the initiation of synaptic growth, move from the cell body of the sensory neuron to its presynaptic terminals, and from the cell body of the motor neuron to its postsynaptic dendritic spines, we have investigated the anterograde transport machinery in both the sensory and motor neurons of the gill-withdrawal reflex(More)
Neurexin and neuroligin, which undergo heterophilic interactions with each other at the synapse, are mutated in some patients with autism spectrum disorder, a set of disorders characterized by deficits in social and emotional learning. We have explored the role of neurexin and neuroligin at sensory-to-motor neuron synapses of the gill-withdrawal reflex in(More)